Electricity numerical for class 10 CBSE Trend Setter 50 Problems

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1. The current passing through a room heater has been halved. What will happen to the heat produced by it?
 2. An electric iron of resistance 20 ohm draws a current of 5 amperes. Calculate the heat produced in 30 seconds.
 3. An electric heater of resistance 8 ohm takes a current of 15 A from the mains supply line. Calculate the rate at which heat is developed in the heater.
 4. A resistance of 40 ohms and one of 60 ohms are arranged in series across 220 volt supply. Find the heat in joules produced by this combination in half a minute.
5. A resistance of 25 ohm is connected to a 12 V battery. Calculate the heat energy in joules generated per minute.
 6. 100 joules of heat is produced per second in a 4 ohm resistor. What is the potential difference across the resistor?
 7. An electric iron is connected to the mains power supply of 220 V. When the electric iron is adjusted at minimum heating’ it consumes a power of 360 W but at ‘maximum heating’ it takes a power of 840 W. Calculate the current and resistance in each case.
 8. Ten bulbs are connected in a series circuit to a power supply line. Ten identical bulbs are connected in a parallel circuit to an identical power supply line.
1. Which circuit would have the highest voltage across each bulb
2. In which circuit would the bulbs be brighter?
3. In which circuit, if one bulb blows out, all others will stop glowing?
4. Which circuit would have less current in it?
9. Calculate the cost of operating a heater of 500 W for 20 hours at the rate of Rs. 3.90 per unit.
10. Which has a greater resistance, a 100 watt bulb or a 60 watt bulb?
11. How much energy is consumed when a current of 5 amperes flows through the filament (or element) of a heater having resistance of 100 ohms for two hours? Express it in joules.

12. An electric bulb is rated at 220 V, 100 W. What is its resistance?
13. An electric bulb is connected to a 220 V power supply line. If the bulb draws a current of 0.5 A, calculate the power of the bulb.
 14. In which of the following cases more electrical energy is consumed per hour?

Find resistance between A and B in following network[10th chapter Electricity]   To Get Complete Question, Click Here

1. A current of 1 ampere passed through a resistance of 300 ohms
2. A current of 2 amperes passed through a resistance of 100 ohms.
15. Electric kettle rated at 220 V, 2.2 kW, works for 3 hours. Find he energy consumed and the current drawn. W
16. In a house two 60 W electric bulbs are lighted for 4 hours, and three 100 W bulbs for 5 hours everyday. Calculate the electric energy consumed in 30 days.
17. If the potential difference between the ends of a wire of fixed resistance is doubled, by how much does the electric power increase?
18. A bulb is rated as 250 V; 0.4 A. Find its : (i) power, and (ii) resistance.
19. For a heater rated at 4 kW and 220 V, calculate (a) the current, b) the resistance of the heater, ) the energy consumed in 2 hours, and d) the cost if 1 kWh is priced at Rs. 4.60.
20. An electric motor takes 5 amperes current from a 220 volt supply line. Calculate the power of the motor arid electrical energy consumed by it in 2 hours.
21. Which uses more energy: a 250 W TV set in 1 hour or a 1200 W Toaster in 10 minutes?
22. An electric bulb is rated as 10 W, 220 V. How many of these bulbs can be connected in parallel across the two wires of 220 V supply line if the maximum current which can be drawn is 5 A.
23. How much work is done in moving a charge of 2 coulombs from a point at 118 volts to a point at 128 volts?
24. What possible values of resultant resistance one can get by combining two resistances, one of value 2 ohm and the other 6 ohm?
25. If 3 resistances of 3 ohm each are connected in parallel, what will be their total resistance?
26. If five resistances, each of value 0.2 ohm, are connected in series, what will be the resultant resistance?
27. Four resistances of 16 ohms each are connected in parallel. Four such combinations are connected in series. What is the total resistance?
28. An electric bulb of resistance 20 and a resistance wire of 4 are connected in series with a 6 V battery. Draw the circuit diagram and calculate (i)the total resistance of the circuit.(ii) Current through the circuit. (iii)Potential difference across the electric bulb.(iv)Potential difference across the resistance wire.
29. How will you connect three resistors of 2 ohm, 3 ohm and 5 ohm respectively so as to obtain a resultant resistance of 2.5 ohm? Draw the diagram to show the arrangement.
30. How will you connect three resistors of resistances 2ohm, 3 ohm and 6 ohm to obtain a total resistance of: (a) 4 ohm, and (b) 1 ohm?
31. A wire of resistance R is cut into five equal pieces. These five pieces of wire are then connected in parallel. If the resultant resistance of this combination be R then the ratio of resultant to the original will be?
32. A copper wire has a diameter of 0.5 mm and resistivity of 1.6 x 10 m.
1. What will be the length of this wire to make its resistance 10 2ohm?
2. How much does the resistance change if the diameter is doubled?
33. An electric heater which is connected to a 220 V supply line has two resistance coils A and B of 24 resistances each. These coils can be used separately (one at a time), in series or in parallel. Calculate the current drawn when
1. Only one coil A is used.
2. Coils A and B are used in series.
3. Coils A and B are used in parallel.
34. If the length of a wire is doubled by taking more of wire, what happens to its resistance?
35. How does the resistance of a wire change when
1. Its length is tripled?
2. Its diameter is tripled?
3. Its material is changed to one whose resistivity is three times?
36. How much energy is given to each coulomb of charge passing through a 6 V battery?
37. The potential difference between the terminals of an electric iron is 240 V and the current is 5.0 A. What is the resistance of the electric iron?
38. A potential difference of 20 volts is applied across the ends of a resistance of 5 ohms. What current will flow in the resistance?
 39. A resistance of 20 ohms has a current of 2 amperes flowing in it. What potential difference is there between its ends?
 40. A current of 5 amperes flows through a wire whose ends are at a potential difference of 3 volts. Calculate the resistance of the wire.
41. The resistance of an electric lamp filament is 230 ohms. The lamp is switched on when the line voltage is 115 volts. What is the current in the lamp circuit?
42. What is the potential difference between the ends of a conductor of 16 ohm resistance, when a current of 1.5 A flows through it?
 43. Calculate the work done in moving a charge of 4 coulombs from a point at 220 volts to another point at 230 volts.
44. What is the potential difference between the terminals of a battery if 250 joules of work is required to transfer 20 coulombs of charge from one terminal of the battery to the other?
45. How much work is done in moving a charge of 2 C across two points having a potential difference of 12 V?
46. An electric bulb draws a current of 0.25 A for 20 minutes. Calculate the amount of electric charge that flows through the circuit.
47. A radio set draws a current of 0.36 A for 15 minutes. Calculate the amount of electric charge that flows through the circuit.
48. Potential difference between two points of a wire carrying 2 ampere current is 0.1 volt. Calculate the resistance between these points.
49. A simple electric circuit has a 24 V battery and a resistor of 60 ohms. What will be the current in the circuit? The resistance of the connecting wires is negligible.
 50. A wire of resistance R is cut into five equal pieces. These five pieces of wire are then connected in parallel. If the resultant resistance of this combination be R then the ratio of resultant to the original will be?

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CBSE Class 10th Results 2014 comming in last week of May

April 23, 2014, 7:24 am

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CBSE 10th Result 2014: Where to Get

CBSE 10th Result 2014 will be published on this page. Student can register their email id and mobile number to get the CBSE Class 10 Result 2014 updates on their mobile and emails through Email and SMS

CBSE 10th Result 2014: Date of Declaration

CBSE class 10 results 2014 is expected to be declared in the last week of May 2014. The results will be declared on the official CBSE website www.cbse.nic.in. Class 10th board exams are commencing from Saturday, March 01, 2014 to Wednesday, March 19, 2014. CBSE has recently declared the complete class 10th and 12th date sheet.

8th Force And Pressure "Notes and Questions Answers"

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Force

A force is an agent which can change or try to change the state of an object. Force is the product of  mass and acceleration
F = ma
Force has both magnitude and direction, making it a vector quantity. The SI unit used to measure force is the Newton (symbol N), which is equivalent to kg•m•s-2

Actions like picking, opening, shutting, kicking, hitting, lifting, flicking, pushing, pulling are often used to describe certain tasks. Each of these actions usually results in some kind of change in the motion of an object.
A force is a push or pull upon an object resulting from the object's interaction with another object. 

Whenever there is an interaction between two objects, there is a force upon each of the objects. When the interaction ceases, the two objects no longer experience the force. Forces only exist as a result of an interaction.

All forces (interactions) between objects can be placed into two broad categories:

• Contact forces, and
• Non Contact forces

Contact Forces:Contact forces are those types of forces which result when the two interacting objects are perceived to be physically contacting each other. Examples of contact forces include frictional forces, tensional forces, normal forces, air resistance forces, and applied forces.

Non-contact Forces: Non Contact forces are those types of forces which result even when the two interacting objects are not in physical contact with each other, yet are able to exert a push or pull despite their physical separation. Examples of Non Contact forces include gravitational forces.

Types of Contact Forces

Applied Force:- An applied force is a force, which is applied to an object by a person or another object. For example, If a person is pushing a desk across the room, then there is applied force acting upon the object. The applied force is the force exerted on the desk by the person.

Normal Force: - The normal force is the support force exerted upon an object which is in contact with another stable object. For example, if a book is resting upon a surface, then the surface is exerting an upward force upon the book in order to support the weight of the book. On occasions, a normal force is exerted horizontally between two objects which are in contact with each other. For instance, if a person leans against a wall, the wall pushes horizontally on the person.

Frictional Force: - The friction force is the force exerted by a surface as an object moves across it or makes an effort to move across it. There are at least two types of friction force - sliding and static friction. For example, if a book slides across the surface of a desk, then the desk exerts a friction force in the opposite direction of its motion. Friction results from the two surfaces being pressed together closely, causing intermolecular attractive forces between molecules of different surfaces. As such, friction depends upon the nature of the two surfaces and upon the degree to which they are pressed together.

Friction is necessary for every movement in life. Suppose you spill some oil on the floor then it will be difficult for you to walk because of negligible friction.

Air Resistance Force: - The air resistance is a special type of frictional force which acts upon objects as they travel through the air. The force of air resistance is often observed to oppose the motion of an object. This force will frequently be neglected due to its negligible magnitude (and due to the fact that it is mathematically difficult to predict its value). It is most noticeable for objects which travel at high speeds (e.g., a skydiver or a downhill skier) or for objects with large surface areas. When you ride your bike then your hair flip backwards because of air resistance.

Tension Force: - The tension force is the force which is transmitted through a string, rope, cable or wire when it is pulled tight by forces acting from opposite ends. The tension force is directed along the length of the wire and pulls equally on the objects on the opposite ends of the wire.

Spring Force: - The spring force is the force exerted by a compressed or stretched spring upon any object which is attached to it. An object which compresses or stretches a spring is always acted upon by a force which restores the object to its rest or equilibrium position.

For most springs (specifically, for those which are said to obey "Hooke's Law"), the magnitude of the force is directly proportional to the amount of stretch or compression of the spring.

Types of Non-contact Forces

Gravitational Force: - The force of gravity is the force with which the earth, moon, or other massively large object attracts another object towards itself. By definition, this is the weight of the object. All objects upon earth experience a force of gravity which is directed "downward" towards the center of the earth. The force of gravity on earth is always equal to the weight of the object as found by the equation:
F grav = m x g
where g = 9.8 m/s2 (on Earth) and m = mass (in kg)

Magnetic Force:-Attraction or repulsion that arises between electrically charged particles because of their motion; the basic force responsible for the action of electric motors and the attraction of magnets for iron. Electric forces exist among stationary electric charges; both electric and magnetic forces exist among moving electric charges. The magnetic force between two moving charges may be described as the effect exerted upon either charge by a magnetic field created by the other.

The magnetic force on a moving charge is exerted in a direction at a right angle to the plane formed by the direction of its velocity and the direction of the surrounding magnetic field.

Electrostatic Force: - The force exerted by stationary objects bearing electric charge on other stationary objects bearing electric charge. If the charges are of the same sign, then the force is repulsive; if they are of opposite signs, the force is attractive. The strength of the force is described by Coulomb's law. Also called electrostatic force.

The force exerted by a charged body on another charged or uncharged body is known as electrostatic force. This force comes into play even when the bodies are not in contact.

Try making your friend sit on a plastic chair with feet not touching the ground. Then use a towel to rub on the chair or on your friend. After about 30 second of continuing this activity, touch your friend. You will get a mild electric shock. This is because of electrostatic charge in the chair and in your friend’s body. You can notice a layer of dust always sticking to TV screen. This happens because of electrostatic charge.

Pressure

Pressure (symbol: p or sometimes P) is the force per unit area applied to an object in a direction perpendicular to the surface.

Mathematically:

P = F/A

Where: p is the pressure,  F is the normal force,  A is the area

The SI unit for pressure is the pascal (Pa), equal to one newton per square meter (N•m-2 or kg•m-1•s-2).

Friction:  Friction is the force resisting the relative lateral (tangential) motion of solid surfaces, fluid layers, or material elements in contact.

Force of Friction : 

•Friction is a force that is created whenever two surfaces move or try to move across each other. 

• Friction always opposes the motion or attempted motion of one surface across another surface.
• Friction is dependant on the texture of both surfaces.
• Friction is also dependant on the amount of contact force pushing the two surfaces together (normal force).

Factors affecting Friction

Friction depends partly on the smoothness of the contacting surfaces, a greater force being needed to move two surfaces past one another if they are rough than if they are smooth. However, friction decreases with smoothness only to a degree; friction actually increases between two extremely smooth surfaces because of increased attractive electrostatic forces between their atoms.

Friction does not depend on the amount of surface area in contact between the moving bodies or (within certain limits) on the relative speed of the bodies. It does, however, depend on the magnitude of the forces holding the bodies together.
When a body is moving over a horizontal surface, it presses down against the surface with a force equal to its weight, i.e., to the pull of gravity upon it; an increase in the weight of the body causes an increase in the amount of resistance offered to the relative motion of the surfaces in contact.

Types of Friction

Static friction: - Static friction is friction between two solid objects that are not moving relative to each other. For example, static friction can prevent an object from sliding down a sloped surface. The coefficient of static friction, typically denoted as μs, is usually higher than the coefficient of kinetic friction.
An example of static friction is the force that prevents a car wheel from slipping as it rolls on the ground. Even though the wheel is in motion, the patch of the tire in contact with the ground is stationary relative to the ground, so it is static rather than kinetic friction.

The maximum value of static friction, when motion is impending, is sometimes referred to as limiting friction, although this term is not used universally.

Kinetic friction:- Kinetic (or dynamic) friction occurs when two objects are moving relative to each other and rub together (like a sled on the ground). The coefficient of kinetic friction is typically denoted as μk, and is usually less than the coefficient of static friction for the same materials.

• Kinetic friction is when two objects are rubbing against each other. Putting a book flat on a desk and moving it around is an example of kinetic friction.

• Fluid friction is the interaction between a solid object and a fluid (liquid or gas), as the object moves through the fluid. The skin friction of air on an airplane or of water on a swimmer are two examples of fluid friction.

Reducing friction : 

Devices: Devices such as wheels, ball bearings, air cushion or roller bearing can change sliding friction into a much smaller type of rolling friction. Many thermoplastic materials such as nylon, HDPE and PTFE are commonly used for low friction bearings. They are especially useful because the coefficient of friction falls with increasing imposed load.

Lubricants: A common way to reduce friction is by using a lubricant, such as oil, water, or grease, which is placed between the two surfaces, often dramatically lessening the coefficient of friction. The science of friction and lubrication is called tribology. Lubricant technology is when lubricants are mixed with the application of science, especially to industrial or commercial objectives.

Energy of friction

According to the law of conservation of energy, no energy is destroyed due to friction, though it may be lost to the system of concern. Energy is transformed from other forms into heat.

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CBSE ADDA: LIFE PROCESSES CBSE Biology class 10 Key notes prepared by KVS and Delhi Schools for SA-01

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v  Life processes – The processes that are necessary for an organism to stay alive. Eg. Nutrition, respiration, etc.

v  Criteria of life- (i) Growth  (ii) Movement

v  Nutrition- The process in which an organism takes in food, utilizes it to get energy, for growth, repair and maintenance, etc. and excretes the waste materials from the body.

v  Types of nutrition                                                                           

1.      Autotrophic nutrition(Auto =self:  trophos = nourishment) E.g. Plants, Algae, blue green bacteria.

o   Process – Photosynthesis(Photo=light; Synthesis= to combine)

o   Raw materials- (i) Carbon dioxide (ii)Water

o   Equation-                  sunlight                                                                         

o    6CO₂  +  6H₂O                          C₆H₁₂O₆      +     6O₂

                                     Chlorophyll

o   Energy conversion- Light/Solar energy to Chemical energy

o   Role off Chlorophyll- To trap the sun’s energy for photosynthesis

o   Factors- (i) Carbon dioxide (ii) Water(iii)  Light (iv)  Temperature

o   Events/ Steps of photosynthesis-    

(i)       Absorption of light energy by chlorophyll

(ii)      Conversion of light energy to chemical energy & Splitting of water molecule into Hydrogen & oxygen

(iii)   Reduction of Carbon dioxide to Carbohydrate

o   Gaseous exchange- (i) Gas used- Carbon dioxide 

                                     (ii)  By product - Oxygen

o   Source of raw materials-

(i)         Carbon dioxide –Land plants- Air, Aquatic plants- Water

(ii)      Water & Minerals - Soil

2.      Heterotrophic nutrition (Hetero =others:  trophos = nourishment) Eg. Animals, plants lacking chlorophyll like fungi.

(a)    Saprophytic nutrition: Organisms feeds on dead decaying plants or animals material. E.g. Fungi, Bacteria

(b) Parasitic nutrition: Organisms obtain food from the body of another living (host)

o   Endoparasite : Parasite lives inside the body of the host e.g. tapeworm, roundworm.

o   Exoparasite:  Parasite lives on the body of the host. E.g. lice, leech.

 Note- The parasite benefits while the host is usually harmed e.g. Cuscutta-plant parasite (amar bel), plasmodium (malarial parasite).

 (c) Holozoic nutrition: Organism (mostly animals) take in whole food and then digest it into smaller particles with enzyme. Eg. Amoeba, Paramoecium. Animals, human beings.

o   Steps in Holozoic nutrition

(i)                 Ingestion: taking in of food.

(ii)               Digestion: breaking down of complex food into simpler, absorbable form.

(iii)             Assimilation: Utilization of digested food from the body.

(iv)             Egestion: Removing undigested food from the body          

o   Nutrition in human beings

§  Alimentary canal-  

           Mouth → Oesophagus → Stomach → Small intestine  → Large intestine

§  Important gland/juices

         (Refer to figure 6.6 page no.97 of N.C.E.R.T  Text book)

Organ	Gland	Enzyme/Juice	Function
Mouth	Salivary glands	Salivary Amylase	Converts starch into sugar
Stomach	Gastric glands	Gastric juice- (i) Hydrochloric      acid                → (ii)  Pepsin         → (iii) Mucus        →	(a) Kills harmful bacteria that      enters with the food. (b)   Makes the medium alkaline       for the action of Pepsin Digests proteins Protects the inner lining of the stomach from the corrosive action of Hydrochloric acid.
Small intestine	1) Liver 2)   Pancreas	(i) Bile juice      → (ii)  Pancreatic       Juice         Amylase → Trypsin   → Lipase     →	(a) Makes the medium acidic       for the action of Pancreatic      enzymes. (b) Breaks down large fat      molecules into smaller globules      so that enzymes can act upon      them. Converts Carbohydrates to glucose Converts Proteins to Amino acids Converts Fats into Fatty acids & Glycerol

§  Peristaltic movements- Rhythmic contraction of muscles of the lining of Alimentary canal to push the food forward.

§  Sphincter muscle- Helps in the exit of food from the stomach.

§  Villi- Small finger like projections on the walls of-

(v)               Small intestine- To increase the surface area for the absorption of food.

(vi)             Large intestine- For absorption of water.

v  Respiration- The process by which digested food is broken down with the help of Oxygen to release energy.

o   Types of  respiration- (i) Aerobic respiration  (ii)Anaerobic respiration 

Aerobic respiration

Anaerobic respiration

1.  Takes place in presence of Oxygen. 2.  End products- Carbon dioxide & Water 3. More energy is released. 4.  Takes place in Cytoplasm & Mitochondria 5. Complete oxidation of glucose takes place. 6. It occurs in most organisms. 7.  Equation- Glucose→ Pyruvate→ CO2  +  H2O + Energy

1.  Takes place in absence of Oxygen. 2. End products- Ethanol & Carbon dioxide 3. Less energy is released. 4.  Takes place in only in Cytoplasm. 5. Incomplete oxidation of glucose takes place. 6.  It occurs in certain bacteria, yeast & certain tissues of higher organisms. E.g. In humans during vigorous exercise, when the demand for Oxygen is more than the supply, muscle cells respire anaerobically for some time. 7.  Equation- In Yeast- Glucose→ Pyruvate→ Ethanol + H2O + Energy In muscle cells - Glucose→ Pyruvate→ Lactic acid + Energy

• Some common features of Respiratory organs-                                                                            (i) Large surface area- for greater rate of diffusion of respiratory gases.                                   (ii)  Thin permeable walls – to ensure easy diffusion & exchange of gases.                              (iii)  Extensive blood supply- Respiratory organs are richly supplied with blood vessels for quick transport of gases.
• Gaseous exchange in plants-  
• Process – Diffusion
• Direction of diffusion depends on- (i) Environmental conditions

                                                              (ii)  Requirement of the plant.

§  Day time- Carbon dioxide given out during respiration is used for photosynthesis. Therefore only Oxygen is released, which is a major activity during the day.

§  Night time – Only respiration takes place. Therefore only Carbon dioxide is released, which is a major activity during the night.

•  Gaseous exchange in animals-      

§  Terrestrial animals- take Oxygen from the atmosphere.

§  Aquatic animals- take Oxygen dissolved in water. (Oxygen content is low in water, therefore they breathe faster.

• Human Respiratory system-                                                                                                External nostrils → Nasal cavity → Trachea→ Bronchi → Bronchioles →Alveoli

§  Rings of cartilage present in the throat ensure that the trachea (air passage) does not collapse when there is less air in it.

§  Lungs – (i) Present in the thoracic cavity.                                                           

                    (ii)  They are spongy, elastic bags consisting of Bronchi,

                                             Bronchioles and Alveoli

                               Refer to figure 6.9 page no. 104 of N.C.E.R.T  Text book)

• Respiration occurs in two phases-
• (i) External-Breathing, which is a mechanical process.                                                               (ii) Internal - Cellular respiration
• Mechanism of breathing – It includes : (i)Inhalation   (ii) Exhalation
• Exchange of gases-

§  Unicellular organisms- By Diffusion

§  Animals- (i) As the body size is large, diffusion alone is not enough.

                      (ii)  Respiratory pigments also required.

                      (iii) Respiratory pigment in human beings is Haemoglobin,

                             which is present in red blood corpuscles.

                       (iv) It has very high affinity for Oxygen.

                       (iv) Carbon dioxide is more soluble in water thanOxygen, so it

                               Gets dissolves in blood and is thus transported.

v  Transportation

• Transportation in human beings-

§  Blood- (i) It is a fluid connective tissue.

    (ii) Components- (1) Fluid medium- Plasma

                                                         (2)  Red blood corpuscles

                                                         (3)  White blood corpuscles

                                                         (4)  Platelets suspended in plasma

                             (iii)  Plasma transports food, Oxygen, Carbon dioxide,

                                                  Nitrogenous wastes, etc.

§  Functions of blood- (i) Transport of respiratory gases.

                         (ii) Transport of nutrients.

                         (iii) Transport of waste products.

                         (iv)  Defence against infection

§  Blood vessels- (i) Arteries (ii) Veins (iii) Capillaries

Arteries	Veins
1.  Thick walled. 2.  Deep seated. 3.  Carry blood away from the heart. 4.  Carry Oxygenated blood. 5.  Valves absent.	1.  Thin walled. 2.  Superficial.  3.  Carry blood to the heart. 4. Carry Deoxygenated blood. 5.  Valves present

§  Heart-    (Refer to figure 6.10 page no. 106 of N.C.E.R.T  Text book)

      (i) It is a muscular organ, which works as a pump in the circulatory system.

                       (ii)  It is the size of our fist.

                       (iii)  It has two sides, which are separated by a partition so that the oxygenated and

                              deoxygenated blood do not get mixed up.

                       (iv) It has four chambers-

        Two upper chambers called Atria. 

        Two lower chambers called Ventricles.    

§  Working of heart-

Left side- (i)  Left atrium relaxes & the Oxygenated blood enters it from

                                               the lungs through the pulmonary vein.

  (ii)  Left atrium contracts & the blood enters the left ventricle

         through the valve.

  (iii) Left Ventricle contracts and the blood is pumped into the

           largest artery ‘Aorta’ and is carried to all parts of the body.

Right side- (i) Right atrium relaxes & the deoxygenated blood from the body enters it 

                                          through superior and inferior Vena cava.

      (ii)  Right atrium contracts & the blood enters the right Ventricle through

            the valve.

                                             (iii) Right Ventricle contracts and the blood is pumped into the Pulmonary

                                                    artery and is carried to lungs.

§  Valves- Unidirectional to prevent the backward flow of blood.

§  Pulmonary vein is the only vein that carries Oxygenated blood.

§  Aorta is the only artery that carries Deoxygenated blood.

§  Double circulation in man- because the blood passes through the heart twice in one complete cycle of the circulation.

§  Capillaries- (i) Form the connection between arteries & veins.

                                           (ii) Walls are one cell thick only for easy exchange of

                                                  blood.

§  Platelets- Plug the leaks of arteries and veins by clotting the blood.

§  Lymph- Extracellular fluid similar to plasma but colourless with lesser protein.

§  Function of lymph-  (i) Transportation of digested & absorbed fats from

                                            the small intestine.

                                       (ii)  Drains excess fluid from the intercellular spaces

                                              back in the blood.

§  Higher animals-  E.g., birds, mammals.                                                       

(i)                  Oxygenated blood & Deoxygenated blood are completely separate for efficient Oxygen supply.  

(ii)               This is  to fulfil higher energy needs and to maintain body temperature (warm blooded animals). 

§  Amphibians & reptiles- have 3 chambered heat where little mixing of  Oxygenated blood & Deoxygenated blood takes place. Therefore their body temperature varies with the temperature of the environment. (cold blooded animals)                                                                          

• Transportation in plants-

§  Plants need less energy needs- because they do not move and therefore have a slow transport system

§  Transport of water- 

(i)                 Takes place by xylem tissue present in roots, stem, leaves and is therefore interconnected.

(ii)               Root cells take up ions from the soil, which creates a concentration difference between root and soil. Column of water therefore rises upwards.

§  In very tall plants- transpiration creates a suction pressure, which pulls the water upwards.

§  Importance of transpiration-

(i)                 Helps in upward movement of water in plants.

(ii)               It regulates the temperature in plants.   

                 §  Transport of food-

(i)                 Takes place by phloem tissue.

(ii)               Movement of prepared food in plants is called translocation.   

v  Excretion- The biological process of removal of harmful metabolic wastes in living organisms.

v  Excretion in human beings-

(Refer to figure 6.13 page no. 110 of N.C.E.R.T  Text book)

§  Organs of excretory system- (i) Kidneys        (iii) Urinary bladder

                                                    (ii) Ureters         (iv) Urethra

§  Kidneys-

(i)                 Two in number

(ii)               Bean shaped      

(iii)             Present in abdomen on either side of the backbone

(iv)             Basic unit is nephron.

a.       Glomerulus- Group of capillaries (cluster) present in Bowman’s                            capsule to receive blood from renal artery and filters it.

b.      Bowman’s capsule- Cup shaped structure, which contains glomerulus.

c.        Convoluted tubule-is long and reabsorbs vital nutrients like glucose, amino acids, salts, urea and water.

      Note-Vital functions of kidneys- (a) Filtration & removal of Nitrogenous wastes                                                                  

                                          (b)  Reabsorption of vital nutrients

§  Ureters- Transport the urine formed in the kidneys to the urinary bladder.

§  Urinary bladder- Muscular bag like structure to store urine.

§  Urethra- Helps in removal of urine when the Urinary bladder is full.

§  Artificial kidney- Principle: Dialysis

v  Excretion in plants-   

• Gaseous wastes- CO₂ in respiration & O₂ in photosynthesis are removed by the process of diffusion.
• Excess water- is removed by transpiration.
• Other wastes- (i) Stored in cellular vacuoles or in leaves, which fall off or as gums, resins, etc. in old xylem.

                             (ii)  Excreted in soil.

v  Important diagrams-

1.      Open & close stomata

2.      Steps of nutrition in Amoeba

3.      Alimentary canal of human beings/ Digestive system of human beings

4.      Respiratory system of human beings

5.      Structure of heart.

6.      Excretory system of human beings

7.      Structure of nephron

v  Important activities-

1.      To prove that chlorophyll is necessary for photosynthesis. Watch

2.      To prove that Carbon dioxide is necessary for photosynthesis. Watch   II   Watch

3.      To prove that light is necessary for photosynthesis.Watch

4.      To prove that product of fermentation is Carbon dioxide.Watch

5.      To prove that leaves lose water by transpiration.Watch   II   Watch

6.      To study the action of salivary amylase on starch.Watch

7.      To demonstrate that Carbon dioxide is present in exhaled air.Watch

8.      To demonstrate the process of transpiration in plants.Watch

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Synthetic Fibres and Plastics CBSE Class Eight Trend setter Study Notes

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8^th synthetic materials

Þ       Synthetic materials are kinds of materials obtained from the synthesis of chemicals.

Þ     The chemicals used for synthetic materials are obtained from petroleum and natural gas(methane)

Þ     Petroleum and natural gas is compound of hydrogen and oxygen called hydrocarbon.

Þ     Monomers are simple chemical molecules of hydrocarbon.

Þ     When monomers join end to end form a long chain of monomers called polymers. The process of the formation of polymers is called polymerization.

Þ     Cellulose [beet root] is polymers of glucose while Hemoglobin is polymers of amino acid.

Þ     Fibres are thin thread like materials used to prepared cloths.

Þ     Fibres obtained on mixing natural and synthetic fiber are called semi synthetic fibre. e.g. rayon

Rayon

Þ     Rayon is synthetic fibres obtained from cellulose.

Þ     Rayon are of three types: Viscose Cupreammonium (cupro)  and acetate rayons.

Viscose Rayon

Þ     In industry cellulose dissolved in mixture of sodium hydroxide (NaOH) and CS₂ (carbon disulphide) to get Viscous liquid [semi solid] called viscose.

Þ     Viscose is forced to spinnerets [an apparatus having small holes like shower] into an acid bath [through solution of acid like H₂SO₄] . Thus filaments of rayon are obtained which is spun into thread.

Cupro Rayon

Þ     Cupro Rayon are obtained on dissolving cellulose into solution of CuSO₄ and NH₄ . The dissolve solutions forced to spinnerets into an acid bath to get filaments of cuprammonium rayon are obtained which is spun into thread.

Acetate Rayon

Þ     Acetate Rayon is obtained on dissolving cellulose into solution of Acetate and H₂SO₄.

Rayon in our daily life

Þ     Rayon mixed with cotton or silk to make smooth and silky cloth in textile industry.

Þ     Rayon mixed with wool to make carpet.

Þ     Rayon are also used for making reinforced tyre, bangles and surgical dressing

Þ     The name Nylon derived from the New York [NY] and London[LON] as Nylon was first produce in both places at same time.

NYLON

Þ     Nylon (polyamides) was first prepared in 1935 chemically.

Þ     Nylon are prepared using cyclic hydrocarbon Benzene(C6H6)

Þ     Nylon has silk like texture and high tensile strength[Drawn into long thin straps]

Nylon in our daily life

Þ     Nylon is mainly used for making ropes, woman’s wear, fishing net, sari socks and tie

Polyster

Þ     Polyster is obtained from polymer of ethene. It has maximum stretchable strength.

Þ     Terylene, Dacron are kinds of Polyster used for dress, cloth and curtain.

Þ     Terylenemixed with cotton and wood to produce terycot and terry wool respectively.

Þ     Polysters are also used for making sail for sail boat and conveyor belts.

 Acrylics

Þ     Acrylics fibres are obtained on dissolving acetylene[C₂H₂] into suitable solvent like HCN and then forced to spinneret because acetylene decompose without melting.

 Acrylics in our daily life

Þ     They are light and soft like wool. The y are crimpy (wavy) and straight like Polyster thus appear to be bulky and look like wool.

Þ     They are resistant to weather as they are not easily acted upon by moisture.

Advantages of synthetic fibres

Þ     Having long lasting luster and do not turn yellow with age

Þ     Easy to clean and dry up quickly

Þ     Durable and do not shrink on washing

Þ     They are less expensive than cotton

Þ     They do not depend on plants or animal like cotton

Advantages of synthetic fibres

Þ     The get electrically charged in dry weather and cause skin irritation

Þ     The melt and form sticky beads  on heating. There is always a risk of getting burn in kitchen

Þ     They are hydrophilic as do not absorb sweat and moisture thus uncomfortable to wear.

Þ     They are non bio degradable and cause pollution.

Þ     They are good absorber of radiant heat and not fit in summer.

Good to more good

To make make wide spread use of synthetic material it is mixed with natural fibre .There are called blend fibre.

PLASTIC

Þ     Plastic : Any material which can be molded into any desirable shape on heating is called plastic

Þ     Petroleum product such that Ethane, propane, benzene ,toluene etc are used for manufacturing plastic.

		Plastic
	Thermoplastic			Thermosetting

Thermosetting Plastic

Þ     Thermosetting plastics are kind of plastic which once moulded cannot moulded again by heating.

Þ     Thermosetting plastics are kind of plastic whose polymers form highly cross linked chain on heating.

Þ     Bakellite , melanin, Formaldehyde are some of the examples of Thermosetting Plastic

Thermoplastic Plastic

Þ     Thermoplastic are kind of plastic which can be moulded again and again by heating and easily reused.

Þ     PVS, Polysterine , nylon , polythine are some of the examples of Thermoplastic Plastic

Þ     Polymers of thermoplastic Plastic  have long chain without cross linked to each other.

Characteristics of plastic

Þ     Plastic has much less toughness as compared to metal

Þ     having light weight

Þ     It is not affected by acids and bases.

Þ     Plastic are non bio degradable as it is weather resistant

Þ     Plastic are bad conductor of heat and electricity

Þ     Plastic melts on heating

Some of the  common plastics are

a. Polythene

Þ     it is obtained from polymerization of ethene. it is non bio degradable .

Þ     it is a kind of thermosetting plastic

Þ     it is insoluble in any solvent

Þ     it is light weight

Þ     it is anti corrosion and insulator

Þ     it is used for making bag ,adhesive tap, electric wire cover and can

b. Polyvinyl chloride (PVC)

Þ     it is use for making sole of shoe

Þ     it is use for making covering of electric wire

Þ     it is use for making sanitary fittings

c. Polysterine

Þ     It is a polymer of polythene .

Þ     it is a kind of thermosetting plastic

Þ     it is highly transparent

Þ     it is use for making cups of hot drink , toy etc.

Þ     it is use for safe packaging of expensive items

Þ     it is use for making Styrofoam[themocole]

Þ     it is use as insulating material in refrigerator

d. Teflon

Þ     It is prepared by using tera- fluroethene.

Þ     Heat and chemical are not effective on Teflon

Þ     it is use for making non stick cooking were

Þ     it is use for making corrosive proof coating in industry

e. Bakelite

Þ     it is a kind of thermosetting plastic

Þ     it is use for making electrical switches and plug

Þ     it is use for making gear wheel

Þ      it is use for making table top

Þ     it is use for making comb, pen bodies and photograph records

f. Melanin

Þ     It is hard and highly polished polymers used for making unbreakable kitchen were.

Some of the common synthetic polymers not used in textiles industry
S. No.	Polymers	Use to make
1.	Polythene	Packaging material, carry bag, bottle
2.	Polypropene	Bottles, Crates
3.	PVC	Pipes, Insulation
4.	Teflon	Non stick Kitchen were
5.	Polystyrene	Foam, Thermocol
6.	Bakelite	Electrical insulation, Button]
7.	Lexan	Bulletproof glass
8.	Melanin	Crockery
9.	Perspex	Window of car, train and aircraft
10.	Vinyl rubber	Rubber, eraser
11.	Neoprene	Rubber
12.	Poly[styrene –butadiene ]	Rubbers ,Bubble gums

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Minimum 25 percent Marks Required to pass SA-1 and SA-2 in class-IX

May 13, 2014, 11:50 pm

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CBSE has issued a circular on 1st May 2014 stating that students who fail to get minimum 25% marks in SA-1 and SA-2 (class-IX) will have to reappear in exam within a month else they will be declared not successful. However, the overall qualifying percentage to go to next class will be 33% as earlier (in each subject out of 100).

It would be mandatory for a student to appear in both the summative assessments in both classes IX and X. In medical cases, the class-IX student have to appear in improvement exam within a month from the date of declaration of result.

To read the complete circular click Here.

Apply for Rechecking or Verification of Grades in CBSE Class 10

May 21, 2014, 7:25 am

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If you are not satisfied with the grades you received in class 10 examination, you can apply for rechecking or verification of grades in class-10. There are two schemes for applying the same :

(1) Students who gave school based examination that is Scheme-I

(2) Students who gave board based examination that is Scheme-II

Scheme-I
Students who have appeared under Scheme-I would apply for verification of grades to the schools only and schools would verify their answer book and communicate the result.

Scheme-II

(1) For urgent verification, applications should be made online within 5 days from the date of declaration of result. The fee will be Rs.300/- per subject.
(2) Applications can also be made online within 21 days from the date of declaration of result, with fee of Rs.200/- per subject.
(3) The past practice of applying for verification of Grades at designated schools in case of Regional Office Delhi and respective Regional Offices (in other cases) has been done away with. The applications for verification of marks will now be received online only.
(4) For 2014 examination, the fee will be received only through E-challan. The candidates will have to deposit the same by visiting the identified Bank branch.
(5) For details, the candidates are advised to see the Notice on the CBSE website www.cbse.nic.in.

The result of verification of grades will be available on the Board’s website. The candidates whose result gets revised after verification of grades will be intimated through letter also by the Regional office concerned.

Improvement of Performance examination CBSE 2014 on July 16, 2014

May 21, 2014, 7:29 am

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CBSE Class 10 Compartment Exam on July 16, 2014

Improvement of Performance examination (Improvement or Compartment exam) will be taken on July 16, 2014 for CBSE class-10. The Improvement examination for class 10 will be conducted by CBSE for all candidates who scored E grade or scored D (or higher) but wish to improve the grades. All students who appeared in 2014 examination will get only and only ONE CHANCE to appear in improvement examination in the month of July 2014.

The number of attempts for Improvement of Performance for Class X has been reduced to one from five w.e.f. 2013 examination. The candidates shall appear for the Improvement of  Performance conducted by the Board in July/ School by July, as per the option exercised for the Main examination held in March the same year. However, for candidates who have appeared in the 2012 examination and placed in the category ‘IMPROVEMENT OF PERFORMANCE’ shall get upto five chances.

The first chance Improvement of Performance Test under Scheme-II will commence from 16th July, 2014. Regular candidates will route their requests through the Head of institution. The Heads of Institutions will ensure that the list of Improvement of Performance candidate reaches the respective regional offices without late fee upto 21.06.2014 or with late fee of Rs. 10/- per day upto 30.06.2014.

Improvement of Performance (IOP) under Scheme-I (school based examination) will be held by July and conducted by the schools.

Application forms for private / Improvement of Performance candidates for Delhi region will be issued to the candidates along with Mark Statements from their respective Schools/Examination Centers.

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8th Microorganisms Trend Setter Quick Revision

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Microorganisms

Definition

The organisms which cannot be observed with the naked eye and can be seen only through a microscope are called microorganisms or microbes.

Food and water become unsafe for consumption due to the presence of harmful organisms, commonly referred to as germs. These germs are so small that they are invisible to the naked eye, but can often cause dangerous diseases.

Since these organisms can be seen only through a microscope, they are called microorganisms or microbes.

When the body is attacked by germs or pathogens, medicines called antibiotics are given. Antibiotics act against the bacteria within the body, without harming the person.

Microorganisms

Microorganisms are present in the air, water, food and even inside our bodies. While a majority of the microbes are harmless, some of them have the capability of causing dangerous diseases.

			Microorganisms
Bacteria	Algae	Fungi		Protozoa		Viruses

Microorganisms play an important role in our lives. Some of them are beneficial in many ways whereas some others are harmful and cause diseases. 

Microorganisms are used for the large scale production of alcohol, wine and acetic acid (vinegar). Yeast is used for commercial production of alcohol and wine. For this purpose yeast is grown on natural sugars present in grains like barley, wheat, rice and crushed fruit juices, etc.

Whenever we fall ill the doctor may give us some antibiotic tablets, capsules or injections such as of penicillin. The source of these medicines is microorganisms. These medicines kill or stop the growth of the disease-causing microorganisms. Such medicines are called antibiotics. These days a number of antibiotics are being produced from bacteria and fungi. Streptomycin, tetracycline and erythromycin are some of the commonly known antibiotics which are made from fungi and bacteria. The antibiotics are manufactured by growing specific microorganisms and are used to cure a variety of diseases. Antibiotics are even mixed with the feed of livestock and poultry to check microbial infection in animals. They are also used to control many plant diseases. 

When a disease-carrying microbe enters our body, the body produces antibodies to fight the invader. The body also remembers how to fight the microbe if it enters again. So, if dead or weakened microbes are introduced in a healthy body, the body fights and kills them by producing suitable antibodies. The antibodies remain in the body and we are protected from the disease causing microbes. This is how a vaccine works. Several diseases, including cholera, tuberculosis, smallpox and hepatitis can be prevented by vaccination.
Some microorganisms live inside our body. They help in certain functions of our bdoy systems. For example some bacteria in our gastrointestinal tract help in digestion. These type of organisms which reside in our body and are beneficial as well are called commensals. 

Microorganisms are harmful in many ways. Some of the microorganisms cause diseases in human beings, plants and animals. Such disease-causing microorganisms are called pathogens. Some microorganisms spoil food, clothing and leather.

Pathogens enter our body through the air we breathe, the water we drink or the food we eat. They can also get transmitted by direct contact with an infected person or carried through an animal. Microbial diseases that can spread from an infected person to a healthy person through air, water, food or physical contact are called communicable diseases. Examples of such diseases include cholera, common cold, chicken pox and tuberculosis.

Disease— causing Microorganisms in Animals

Several microorganisms not only cause diseases in humans and plants, but also in other animals. For example, anthrax is a dangerous human and cattle disease caused by a bacterium. Foot and mouth disease of cattle is caused by a virus.

Several microorganisms cause diseases in plants like wheat, rice, potato, sugarcane, orange, apple and others. The diseases reduce the yield of crops. They can be controlled by the use of certain chemicals which kill the microbes.

Food poisoning could be due to the consumption of food spoilt by some microorganisms. Microorganisms that grow on our food sometimes produce toxic substances. These make the food poisonous causing serious illness and even death. So, it is very important that we preserve food to prevent it from being spoilt.
Microorganisms spoil our food. Spoiled food emits bad smell and has a bad taste and changed colour.

Chemical Method: Salts and edible oils are the common chemicals generally used to check the growth of microorganisms. Therefore they are called preservatives. We add salt or acid preservatives to pickles to prevent the attack of microbes. Sodium benzoate and sodium metabisulphite are common preservatives. These are also used in the jams and squashes to check their spoilage.

Our atmosphere has 78% nitrogen gas. Nitrogen is one of the essential constituents of all living organisms as part of proteins, chlorophyll, nucleic acids and vitamins. Certain bacteria and blue green algae present in the soil fix nitrogen from the atmosphere and convert into compounds of nitrogen. Once nitrogen is converted into these usable compounds, it can be utilised by plants from the soil through their root system. Nitrogen is then used for the synthesis of plant proteins and other compounds. Animals feeding on plants get these proteins and other nitrogen compounds.

                                                                    

Classification of Microorganism

Microbes are mainly classified into five major groups :

Bacteria :

Bacteria (singular: bacterium) are single-called organisms that vary in shape and size. Some bacteria are  round or oval (coccus), others are rod-shaped (bacillus) or spiral. Some bacteria are autotrophic as they contain chlorophyll, but most of them are heterotrophic, showing saprophytic or parasitic mode of nutrition.

Algae :

Autotrophic organisms having undifferentiated plant bodies are called algae (singular: alga). Algae occur abundantly, like grass in aquatic habitats and are also called 'grass of water'.

Fungi :

Fungi (singular: fungus) are a group of plant-like organisms exhibiting heterophic (saprophytic or parasitic) nutrition. They are commonly found on bread, leather, cotton, paper, etc. Fungi grow vigorously in damp, warm, dark places, Yeast, moulds and mushrooms are forms of fungi. Yeast, moulds and mushrooms are forms of fungi. Yeast is commonly used for baking breaed, cakes, etc. The yeast ferments sugar present in the wheat and converts it to carbon dioxide and alcohol. The gas expands, so that the dough (kneaded atta) rises, giving shape and flavour to the preparation.

Protozoa :

Unicellular organisms that exhibit animal-like characteristics are called protozoa (singular: protozoan). The word protozoan literally means 'the first animal'. Most protozoa are heterotrophic.

Viruses :

A virus is a microorganism which exhibits characteristics of living as well as non-living things. Viruses exhibit a variety of shapes, having simple structure. Reproducing only inside a living organism, viruses can cause many diseases.

Useful Microorganisms

Humans have many microorganism in their in their digestive system that contribute to overall health. The microbial community in humans not only protects us from disease, but also provides necessary vitamins.

Bacteria also help in nitrogen fixation in production of antibiotics, etc. Algae are also useful in a number of industries. Therefore, even through microbes are responsible for food spoilage and many diseases, they can also be very helpful.

Yoghurt or curd (dahi) is the commonest example of beneficial use of microbes. Youghurt is a part of our daily diet and we eat it in various forms, with different flavour. This dahi is made from milk by the action of a bacterium called lactobacillus or latic acid bacteria. It converts the sugar in milk (lactose) to lactic acid, giving curd its sour taste. This process was initially used as a way to preserved milk.

Lactose  ------Lactobacillus----------> Lactic Acid (Yoghurt)

Curdling of milk takes places naturally, due to heat (specially in summer).

Curding of milk also takes place due to addition of any of the acid products such as sour curd, lemon juice and even tomato juice.

Microorganisms and we

Microorganisms play an important role in our lives. Some of them are beneficial in many ways whereas some others are harmful and cause diseases.

Commercial Use of Microorganisms

Microorganisms are used for the large scale production of alcohol, wine and acetic acid (vinegar). Yeast is used for commercial production of alcohol and wine. For this purpose yeast is grown on natural sugars present in grains like barley, wheat, rice and crushed fruit juices, etc.

Medicinal Use of Microorganisms

Whenever we fall ill the doctor may give us some antibiotic tablets, capsules or injections such as of penicillin. The source of these medicines is microorganisms. These medicines kill or stop the growth of the disease-causing microorganisms. Such medicines are called antibiotics. These days a number of antibiotics are being produced from bacteria and fungi. Streptomycin, tetracycline and erythromycin are some of the commonly known antibiotics which are made from fungi and bacteria. The antibiotics are manufactured by growing specific microorganisms and are used to cure a variety of diseases. Antibiotics are even mixed with the feed of livestock and poultry to check microbial infection in animals. They are also used to control many plant diseases.

Vaccine

When a disease-carrying microbe enters our body, the body produces antibodies to fight the invader. The body also remembers how to fight the microbe if it enters again. So, if dead or weakened microbes are introduced in a healthy body, the body fights and kills them by producing suitable antibodies. The antibodies remain in the body and we are protected from the disease causing microbes. This is how a vaccine works. Several diseases, including cholera, tuberculosis, smallpox and hepatitis can be prevented by vaccination.

Increasing Soil Fertility
Some bacteria and blue green algae are able to fix nitrogen from the atmosphere to enrich soil with nitrogen and increase its fertility. These microbes are commonly called biological nitrogen fixers.

Commensals:

Some microorganisms live inside our body. They help in certain functions of our bdoy systems. For example some bacteria in our gastrointestinal tract help in digestion. These type of organisms which reside in our body and are beneficial as well are called commensals.

Apart from them certain food like curd, contain beneficial bacteria.

Harmful Microorganisms

Microorganisms are harmful in many ways. Some of the microorganisms cause diseases in human beings, plants and animals. Such disease-causing microorganisms are called pathogens. Some microorganisms spoil food, clothing and leather.

Disease— causing Microorganisms in Humans

Pathogens enter our body through the air we breathe, the water we drink or the food we eat. They can also get transmitted by direct contact with an infected person or carried through an animal. Microbial diseases that can spread from an infected person to a healthy person through air, water, food or physical contact are called communicable diseases. Examples of such diseases include cholera, common cold, chicken pox and tuberculosis.

There are some insects and animals which act as carriers of disease causing microbes. Housefly is one such carrier. The flies sit on the garbage and animal excreta. Pathogens stick to their bodies. When these flies sit on uncovered food they may transfer the pathogens. Whoever eats the contaminated food is likely to get sick. Another example of a carrier is the female Anopheles mosquito, which carries the parasite of malaria. Female Aedes mosquito acts as carrier of dengue virus.

Some Common Human Diseases caused by Microorganisms

Disease— causing Microorganisms in Animals

Several microorganisms not only cause diseases in humans and plants, but also in other animals. For example, anthrax is a dangerous human and cattle disease caused by a bacterium. Foot and mouth disease of cattle is caused by a virus.

Disease— causing Microorganisms in Plants

Several microorganisms cause diseases in plants like wheat, rice, potato, sugarcane, orange, apple and others. The diseases reduce the yield of crops. They can be controlled by the use of certain chemicals which kill the microbes.

Food Poisoning

Food poisoning could be due to the consumption of food spoilt by some microorganisms. Microorganisms that grow on our food sometimes produce toxic substances. These make the food poisonous causing serious illness and even death. So, it is very important that we preserve food to prevent it from being spoilt.

Food Preservation

Microorganisms spoil our food. Spoiled food emits bad smell and has a bad taste and changed colour.

Common methods to preserve food in our homes.

Chemical Method: Salts and edible oils are the common chemicals generally used to check the growth of microorganisms. Therefore they are called preservatives. We add salt or acid preservatives to pickles to prevent the attack of microbes. Sodium benzoate and sodium metabisulphite are common preservatives. These are also used in the jams and squashes to check their spoilage.

Preservation by Common Salt: Common salt has been used to preserve meat and fish for ages. Meat and fish are covered with dry salt to check the growth of bacteria. Salting is also used to preserve amla, raw mangoes, tamarind, etc.

Preservation by Sugar: Jams, jellies and squashes are preserved by sugar. Sugar reduces the moisture content which inhibits the growth of bacteria which spoil food.

Preservation by Oil and Vinegar: Use of oil and vinegar prevents spoilage of pickles because bacteria cannot live in such an environment. Vegetables, fruits, fish and meat are often preserved by this method.

Heat and Cold Treatments: You must have observed your mother boiling milk before it is stored or used. Boiling kills many microorganisms.

Similarly, we keep our food in the refrigerator. Low temperature inhibits the growth of microbes. Pasteurized milk can be consumed without boiling as it is free from harmful microbes. The milk is heated to about 700C for 15 to 30 seconds and then suddenly chilled and stored. By doing so, it prevents the growth of microbes. This process was discovered by Louis Pasteur. It is called pasteurization.

Storage and Packing: These days dry fruits and even vegetables are sold in sealed air tight packets to prevent the attack of microbes.

Nitrogen Fixation: Rhizobium is involved in the fixation of nitrogen in leguminous plants (pulses). Sometimes nitrogen gets fixed through the action of lightning. But the amount of nitrogen in the atmosphere remains constant.

Nitrogen cycle

Our atmosphere has 78% nitrogen gas. Nitrogen is one of the essential constituents of all living organisms as part of proteins, chlorophyll, nucleic acids and vitamins. Certain bacteria and blue green algae present in the soil fix nitrogen from the atmosphere and convert into compounds of nitrogen. Once nitrogen is converted into these usable compounds, it can be utilised by plants from the soil through their root system. Nitrogen is then used for the synthesis of plant proteins and other compounds. Animals feeding on plants get these proteins and other nitrogen compounds.

When plants and animals die, bacteria and fungi present in the soil convert the nitrogenous wastes into nitrogenous compounds to be used by plants again. Certain other bacteria convert some part of them to nitrogen gas which goes back into the atmosphere. As a result, the percentage of nitrogen in the atmosphere remains more or less constant.

Steps Involved in Nitrogen Cycle

 The atomspheric nitrogen is fixed into nitrogen compounds like nitrates hy Rhizobium bacteria, bluegreen
algae, lightning or industrial method.

 The plants absorb nitrate compounds from the soil and water and convert them into plant proteins.

 The plants are eaten up by animals and thus plant protiens are used for making animal proteins.

 When the plants and animals die, the putrefying bacteria and fungi present in the soil decompose the
protiens of dead plants and animal into ammonia. This process is called ammonification.

 Ammonia thus formed is converted first into nitrites and then into nitrates by the action of Nitrosomonas
and Nitrobacter bacteria respectively. The process is called nitrification. These nitrates are again
absorbed by plants and the cycle is repreated.

 The soil contians denirifying bacteria called Pseudomonas which convert nitrate form of nitrogen into
free nitrogen which goes back into the atmosphere. The process is called denitrification.

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Tissues in Plants and Animals biology notes for 9

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1. Tissue is a group of cells having similar origin, structure& function. Study of tissues is called Histology

2. In unicellular organism (Amoeba) single cell performs all basic functions, whereas in multi-cellular organisms (Plants and Animals) shows division of labor as Plant tissue & Animal tissues.

3. Plant tissues are two types: Meristems & Permanent tissues.

4. Meristems: The Meristems are the tissues having the power of cell division. It is found on those region of the plant which grows.

5. Types of Meristems;

1. The Apical meristems – It is present at the growing tip of the stem and roots and increases the length.

2. The lateral meristems - present at the lateral side of stem anf root (cambium) and increases the girth.

3. The intercalary meristems - present at internodes or base of the leaves and increases the length between the nodes.

( Please refer to Fig. 6.2: location of meristems in plant body , NCERT Book Page- 69).

26. Permanent tissues: Two types such as Simple permanent tissues & Complex permanent tissues.

a) Simple permanent tissues: subdivided as

(i): Parenchyma: Tissues provide the support to plants.They are loosly packed and has large intracellular space.

- Parenchyma with chlorophyll which performs photosynthesis is called as chlorenchyma.

- The parenchyma with large air spaces to give buoyancy is called as aerenchyma .Parenchyma also stores food and water.

(ii) Collenchyma: Tissue provides mechanical support, thickened at the corners, have very little intercellular space. It allows easy bending of various parts of a plants without breaking

(iii) Sclerenchyma: Tissue makes the plant hard and stiff, thickened due to lignin and no intercellular space. Cells of this tissue are dead and commonly seen in the husk of coconut.

(iv) Guard cells& Epidermal tissue: the tissue aids in protection and exchange of gases. Guard cells kidney shaped in dicots, dumb bell shaped in monocots to guard the stomata. The epidermal tissues of roots aid in absorption of water and minerals. The epidermal tissues in desert plants have a thick waxy coating of Cutin with waterproof quality. The epidermal tissues form the several layer thick Cork or the Bark of the tree.

(Please refer to Fig. 6.3- 6.6, NCERT Book Page-70-73).

b) Complex permanent tissues: The complex tissues are made of more than one type of cells. All these cells coordinate to perform a common function.

They are subdivided as;

Xylem: It consists of tracheids, vessels, xylem parenchyma and xylem fibers. The cells have thick walls,

Function - aids in conduction of water and minerals.

Phloem: It consists of sieve tubes, companion cells, phloem parenchyma, and phloem fibers.

Function - Phloem transports food material to other parts of the plants.

(Please refer to Fig. 6.7, NCERT Book Page-73).

6. Animal tissues: Sub divided as epithelial tissue, connective tissue, muscular tissue and nervous tissue.

i. Epithelial tissue: It is a protective covering forming a continuous sheet. Simple epithelium is the one which is extremely thin in one layer, whereas stratified epithelium are arranged in pattern of layers.

Depending on shape and function they are classified as:

a) Squamous epithelium in the lining of mouth and esophagus.

b) Cuboidal epithelium in the lining of kidney tubules and salivary glands.

c) Columnar epithelium in the intestine &Columnar epithelium with cilia in the lining of respiratory tract.

d) Glandular epithelium in the Glands aids in a special function as gland cells, which can secrete at the epithelial surface.

(Please refer to Fig. 6.9, NCERT Book Page-75).

ii) Connective Tissue: Five Types, such as;

a) Blood: The Blood is a fluid connective tissue. Blood plasma has RBCs (Red Blood Cells) WBCs (White Blood Cells) and platelets. Blood plasma contains proteins, salts and hormones. Blood flows and transports gases, digested food, hormones and waste materials.

b) Bone: The bone is a connective tissue with hard matrix, composed of calcium and phosphorus. A bone is connected by another bone with another connective tissue called ligaments. A bone is connected by muscle with another connective tissue called tendon.

c) Cartilage: The cartilage is a connective tissue with solid matrix composed of proteins and sugars. It is commonly seen in nose, ear, trachea, and larynx.

d) Areolar Connective Tissue: It is found between the skin and muscles, around the blood vessels. It supports internal organs and aids in repair of tissues.

e)Adipose Connective Tissue: It is filled with fat globules for the storage of fat. It acts as insulator. (Please refer to Fig. 6.10, NCERT Book Page-76).

Muscular tissues: They have special contractile proteins responsible for movements. Three types, such as; Striated muscles/skeletal muscles/voluntary muscles :

They are cylindrical, un-branched and multinucleated.They have dark bands and light bands.

Unstriated muscles/smooth muscles/involuntary muscles:

They are commonly called as Smooth muscles, having no striations (dark bands/ light bands are absent). Commonly found alimentary canal, uterus, Iris of an Eye. They are spindle shaped. Involuntary in nature

Cardiac Muscles: They are commonly called as Heart muscles, cylindrical, branched and uni-nucleate. Involuntary in nature.(Please refer to Fig. 6.11, NCERT Book Page-77).

Nervous Tissue: The tissue responds to stimuli. The brain, spinal cord and nerves are composed of nervous tissue or neurons. A neuron consists of Cell Body, cytoplasm, Nucleus, Dendrite, Axon, nerve ending. The neuron impulse allow us to move our muscles when we want to respond to stimuli. (Please refer to Fig. 6.12, NCERT Book Page-78).

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As per the new rule applicable from 2014 on wards the rechecking (verification of marks), getting photocopy of answer book and applying revaluation is now three step process. No one is allowed to jump steps or skip any step. All the steps have to be completed online. No offline application will be accepted.

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Q.1. Based on Euclid’s algorithm: a = bq + r 

Using Euclid’s algorithm: Find the HCF of 825 and 175.

Explanation:
Step 1. Since 825>175. Divide 825 by 175. We get, quotient = 4 and remainder = 125. This can be written as 825 = 175 x 4 + 125
Step II. Now divide 175 by the remainder 125. We get quotient = 1 and remainder = 50. So we write 175 = 125 x 1 + 50.
Step III. Repeating the above step we now divide 125 by 50 and get quotient = 2 and remainder = 25. so 125 = 50 x 2 + 25
Step IV.
Now divide 50 by 25 to get quotient = 2 and remainder 0. Since remainder has become zero we stop here. Since divisor at this stage is 25, so the HCF of 825 and 175 is 25.
Solution: This is how a student should write answer in his answer sheet:
Since 825>175, we apply division lemma to 825 and 175 to get
825 = 175 x 4 + 125.
Since r ≠ 0, we apply division lemma to 175 and 125 to get
175 = 125 x 1 + 50
Again applying division lemma to 125 and 50 we get,
125 = 50 x 2 + 25.
Once again applying division lemma to 50 and 25 we get.
50 = 25 x 2 + 0.
Since remainder has now become 0, this implies that HCF of 825 and 125 is 25.

Problems for practice;

1. Find HCF of the following pairs using Euclid’s division Lemma
2. 34782 and 1892
3. 588 and 240
4. 80784 and 628

Q.2. Based on Showing that every positive integer is either of the given forms:

Solved example:
Prove that every odd positive integer is either of the form 4q + 1 or 4q + 3 for some integer q.

Explanation:
Euclid’s division lemma a= bq + r.

Comparing this with the given integers (4q + 1) we get that b should be 4.If we divide any number by 4 possible remainders are 0, 1, 2 or 3 because fourth number will again be divided by 4. Ex 12 ÷ 4, r=0; 13÷4, r=1; 14÷ 4, r=2; 15÷4, r=3; 16÷4 once again r= 0.Hence possible remainders are 0, 1, 2 or 3. If r = 0, then we get a = 4q, If r = 1 we get a= 4q + 1 and so on till r = 3 which will give a= 4q + 3. Since we want only odd integers our choices are 4q + 1 and 4q + 3.

Solution:
Let a be any odd positive integer (first line of problem) and let b = 4. Using division Lemma we can write a = bq + r, for some integer q, where 0≤r<4. So a can be 4q, 4q + 1, 4q + 2 or 4q + 3. But since a is odd, a cannot be 4q or 4q + 2. Therefore any odd integer is of the form 4q + 1 or 4q + 3.

Practice questions:
   

i. Write the possible remainders when a number is divided by
a. 5            b. 3              c. 7                    d. 2.

ii. Prove that every even positive integer is either of the form 6q, 6q + 2 or 6q + 4.    

iii. Prove that every positive integer is either of the form 3q, 3q + 1 or 3q + 2 for some integer q.

Q. 3. Based on LCM and HCF:
Formula: LCM x HCF = product of numbers Or product of numbers = LCM x HCF

Hint: If LCM or HCF is to be found then use the first formula. IF value of any of the numbers is to found use second formula. That is, always keep the unknown variable on the LHS to avoid confusion.

Solved example:
a. Find HCF (26,91) if LCM(26,91) is 182
Sol: We know that LCM x HCF = Product of numbers.
or 182 x HCF = 26 x 91
or HCF = 26 x 91 = 13
182
Hence HCF (26, 91) = 13.

b. LCM and HCF of two numbers are 3024 and 6 respectively. If one of the number is 336 find the other number.
Sol: We know that
Product of numbers = LCM x HCF
Or Number = LCM x HCF
Given number
Or number = 3024 x 6 = 54
336
Hence the other number is 54.

Solve similar questions from your text book.
Q. 4. Based on irrational numbers.

By heart the following jingles.

1. Let us assume on the contrary the √__ is rational. That is we can find co-primes a and b ( b≠0) such that √__ = a/b.
2. ____ divides a2. Hence it follows that ____ divides a.
3. So we can write a= ____c.

4. ____ divides b2. Hence it follows that ____ divides b.
5. Now a and b have at least ____ as a common factor.
6. But this contradicts the fact that a and b are co-primes.
7. This contradiction has arisen because of our incorrect assumption that √__ is irrational.
8. Hence √__ is rational.

Sample question: prove that √5 is irrational.

Solution:
let us assume on the contrary that √5 is rational. That is we can find co-primes a and b b (≠0) such that √5 = a/b. (1st jingle)
Or √5b = a.
Squaring both sides we get
5b2 = a2.
This means 5 divides a2. Hence it follows that 5 divides a. (2nd jingle)
So we can write a = 5c for some integer c. (3rd jingle)
Putting this value of a we get
5b2 = (5c)2
Or 5b2 = 25c2
Or b2 = 5b2.
It follows that 5 divides b2. Hence 5 divides b. (4th jingle)
Now a and b have at least 5 as a common factor. (5th jingle)
But this contradicts the fact that a and b are co-primes. (6th jingle)
This contradiction has arisen because of our incorrect assumption that √5 is rational. (7th jingle)
Hence it follows that √5 is irrational. (8th jingle)

X Real Numbers : Topics:
1. Euclid's Division Lemma/Algorithm
2. Fundamental Theorem of Arithmetic
3. Irrational Numbers
4. Decimal expression of Rational Number

10th Real Numbers CBSE Test Papers     Download File

Observe the Magnetic field lines around a current carrying loop By jsunil

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Procedure (to be performed in the schoollaboratory)

• Take a long wire and bend it to form a circle.
• Pass the wire through the cardboard such that half the wire is above it and the remaining part of the wire is below the cardboard.
• Join the free ends of the wire to a battery through a plug key.
• Insert the key and pass the current. Sprinkle iron filings on the cardboard and tap gently.

 Observations:

• Concentric circles are formed, which are centred at the point where the wirepasses through the cardboard.
• The lines near the centre of the loop are almost straight. The magnetic field at the centre of the loop is perpendicular to the plane of the loop.
• The concentric circles become larger as we move away from the wire

Procedure ( to be performed in the simulation )

The EJSMagnetic Field from Loops model computes the B-field created by an electric current through a straight wire, a closed loop, and a solenoid. The user can adjust the vertical position of the slice through the 3D field.

• Watch the simulation as the field changes from the field around a long straight current-carrying wire to the field near a coil. Explain what happens to the field. Inside a coil of many loops, why is the field fairly uniform near the center (think about vector addition and what vectors would be adding together near the center).
• There is an arrow on each end of the wire (red and blue).  Which one shows the direction of the current in the wire? Explain.
• The red arrows indicate the resultant direction of the magnetic field due to the loop.
• The blue arrows indicate the resultant direction of the individual segments of wire.

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Time: 3-3and1/2 hr _ Max mark: 100 [includes 10 marks based on Open Text Theme]

Test held in School:

Sadhana Devi Vidyapith, Samastipur - Punjabi Colony [By JSunil]

1 mark

1. As per the law of definite proportional carbon and oxygen combine in ratio 3: 8. Compute the mass of oxygen gas that would be required to react completely with 6 gm carbon.

2. A pore bearing organism like creature “A” belong to a phylum “B” of kingdom Animalia.

3. In which reason is soil erosion very difficult to revert.

2 marks

4. Explain, What is Organ specific manifestation?

5. A man drops a stone of mass 2 kg room the top of a building of height 15m when it reaches the ground, find its kinetic energy.

6. When an object is immersed in the fluid name the two forces acting on it.

3 marks

7. (a) The mass number of an element is 18. It contains 7 electrons. What is the number of proton? and neutron in it.

(b) State the problem of atomic structure which was solved after the discovery of neutron.

8.(a)From Rutherford a - particle scattering experiment give the experimental evidence for deriving the conclusion that

(i) Most of the space inside the atom is empty

(ii) The nucleus of atom is positively charged

(b)An element has mass number 31 and atomic number 15 find

(i) The number of neutron in element

(ii) The number of electron in element

9. Write three point of difference between an atom and molecules

10. Carolus Liniaus gave the two kingdom of classification. Latter it was changed by Ernst Haikel (1894) and in 1959 , ,Whittaker gave the five kingdom classification. Do you think that studying about the work done by earlier scientists or their obsolete theories is useful for student of this generation? Give three reasons.

11.What are phanerogams? Name its two groups along with the criteria of division.

12.A man has an audible range from 20Hz to 20kHz. What are the wave lengths of sound in air corresponding to these two frequencies? (Speed of sound is 344m/s)

13.How does the sound produced by a musical instrument , reach your ears? Astronauts need radio telescope to talk to each other on moon why?

 14. (A) Name the type of energy posses by moving object?

(b) Derive the expression for this energy for an object moving with velocity v and having mass m

15.(a)Define frequency and amplitude. (b)Draw diagram to represent (i) soft sound (ii) Loud sound

16. A solid weight 75g in air and 55.6 g in water. Find the relative density of the solid. Also state if the object will float or sink when immersed in water.

17. How are cloud formed and what bring us rain.

18. Mention any three important roles of water essential for life of organism on the earth’s surface.

5 marks

19.(a)Write chemical formula of all compounds that can be formed by the combination of following ions: Ca²⁺ , K⁺ , Fe³⁺ , Cl^-, SO₄^2-

(b)Molar mass of nitrogen is 14u. What will be the mass of one atom of nitrogen in gram?

20. Fill in the blanks

Disease	microbes	Target organ	Mode of transmission
Meningitis	virus	-----(a)---------	Fecal contamination
Hepatitis	---(b)------	---(c)-------	Contamination water
---(d)-----	Bacteria	Lungs	----(e)------------
Ringworm	fungus	---(f)-------	Indirect Contact
---(g)-------	Virus	Lungs	-----(h)-----------
Dengue fever	-----(i)-----	Whole body	----(j)-----------

21.(a)What kind of food is advised when we fall sick and why

(b)Mention any three basic conditions required for good health.

22. Define frequency and wavelength with reference to sound. Explain what is echo . Write full form of SONAR. Give two application of Ultrasound.

23. (a) Define 1Kwh.

(b) How is the power related to the speed at which an object is lifted?

(c) if an electric iron of 1600W is used for 45 min every day , find the electric energy consumed in month of march.

24. What is meant by depletion of Ozone layer? Mention one important feature of ozone in atmosphere. Identify the factor responsible for creation of ozone hole?
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10^th Polynomials Ch-02-Mathematics [Key points] 

Check point [Formative Assessment]

Þ  Any algebraic expression having non zero integral power (whole number) is called polynomial.

Þ If p(x) is a polynomial in x, the highest power of x in p(x) is called the degree of the polynomial p(x).

Þ A polynomial of degree 1 is called a linear polynomial. For example, 2x – 3, √3x+1,y +√3

Þ A polynomial of degree 2 is called a quadratic polynomial. The name ‘quadratic’ has been derived from the word ‘quadrate’, which means ‘square’.       2x² +  3x + 2 ,y² + 2

Þ Any quadratic polynomial in x is of the form ax² + bx + c, where a, b, c are real numbers and a ≠ 0.

Þ A polynomial of degree 3 is called a cubic polynomial e.g. 2 – x³, x³, √2 x³.

Þ General form of a cubic polynomial is  ax³ + bx² + c x + d, where, a, b, c, d are real numbers and a ≠ 0.

Þ If p(x) is a polynomial in x, and if k is any real number, then the value obtained by replacing x by k in p(x), is called the value of p(x) at x = k, and is denoted by p(k). A real number k is said to be a zero of a polynomial p(x), if p (k) = 0.

Þ Thus, the zero of a linear polynomial is related to its coefficients because if k is a zero of p(x) = ax + b, then p (k) = a k + b = 0, i.e., k  = -b/a

Þ  Zero of a linear polynomial ax + b is −b/a

ÞThe graph of y = ax + b is a straight line like the graph of y = ax + b is a straight line passing through the points (– 2, –1) and (2, 7) and straight line straight line intersects the x-axis at exactly one point

ÞThe linear polynomial ax + b, a ≠ 0, has exactly one zero, namely, the x-coordinate of the point (-b/a , 0) where the graph of y = ax + b intersects the x-axis.

Þ The graph of equation y = ax+ + b x + c has one of the two shapes either open upwards like È (a > 0 ) or open downwards like Ç ( a < 0) . These curves are called parabolas.

Þ The zeroes of a quadratic polynomial ax² + bx + c, a ≠ 0, are precisely the x-coordinates of the points where the parabola representing y = ax² + bx + c intersects the x-axis.

Þ In general, given a polynomial p(x) of degree n, the graph of y = p(x) intersects the x- axis at atmost n[n or less than n]  points.

Þ A polynomial p(x) of degree n has at most n zeroes.

Þ if α and β are the zeroes of the quadratic polynomial p(x) = ax² + b x + c, a ≠ 0, then you know that x – α and x – β are the factors of p(x). 
Therefore, ax² + bx + c = a(x – α) (x – β)=  ax² – a(α + β)x + a α β]

Comparing the coefficients of x², x and constant terms on both the sides, we get  , a = k, b = – k(α + β) and c = kαβ.

This gives            

   α + β = -b/a ; α β = c/a

 Þ Relationship between the zeroes of a cubic polynomial and its coefficients of 

ax³ + bx² + c x + d= a(x-a)(x-b)(x-g)  = ax³ – a(a+b+g)x² + a(ab +bg+ga) - aabg  

Comparing the coefficients of terms on both the sides, we get,  α + β + γ = –b/a; α β + β γ + γ α =c/a; α β γ =– d/a

Þ Division algorithm states that given any polynomial p(x) and any non-zero polynomial g(x), there are polynomials q(x) and r(x) such that p(x) = g(x) q(x) + r(x), where r(x) = 0 or degree r(x) < degree g(x).

Check point [Formative Assessment]

Q. 1. Find the zeroes of the quadratic polynomial x² + 7x + 10, and verify the relationship between the zeroes and the coefficients.

Q.2. Find the zeroes of the polynomial x² – 3 and verify the relationship between the zeroes and the coefficients.

Q.3. Find a quadratic polynomial, the sum and product of whose zeroes are – 3 and 2, respectively.

Q.4. Verify that 3, –1, -1/3 are the zeroes of the cubic   polynomial p(x) = 3x³ – 5x² – 11x – 3, and then verify the relationship between the zeroes and the coefficients.

Q.5. Find a quadratic polynomial if the sum and product of its zeroes respectively √2, 1/3

Q.6. Find all the zeroes of 2x⁴ – 3x³ – 3x² + 6x – 2, if you know that two of its zeroes are √2 and − √2

Q.7. Obtain all other zeroes of 3x⁴ + 6x³ – 2x² – 10x – 5, if two of its zeroes are   √(5/3) , -√(5/3)

Q.8. Find a cubic polynomial with the sum, sum of the product of its zeroes taken two at a time, and the product of its zeroes as 2, –7, –14 respectively

Q.9. If the zeroes of the polynomial x³ – 3x² + x + 1 are a – b, a, a + b, find a and b.

Q.10. If two zeroes of the polynomial x⁴ – 6x³ – 26x² + 138x – 35 are 2 ± √3 , find other zeroes.

Q.11.  If the polynomial x⁴ – 6x³ + 16x² – 25x + 10 is divided by another polynomial x² – 2x + k, the remainder comes out to be x + a, find k and a.

Q.12. If α and β are the zeros of the quadratic polynomial f(x) = x² - p (x+1) - c, Show that (α+ 1) (β + 1) = 1- c.

Q.13. 1.      For which values of a and b , are the zeros of g(x) = x³+2x²+a, also the zeros of the polynomial f(x) =x⁵-x⁴-4x³+3x²+3x+b ? Which zeros of f(x) are not the zeros of g(x)?

(Ans. 1 and 2 are the zeros of g(x) which are not the zeros f(x) and this happens    when    a= -2 , b= -2)

Q.14. 1.      If one zero of the polynomial 3x²- 8x –( 2k + 1) is seven times the other , find both zeroes of the polynomial and the value of k .

( Ans. The zeroes of the given polynomial are 1/3  , 7/3  and the value of k is (-5/3)

Q.14. if (x+a) is a factor of 2x²+2ax+5x+10then find the value of a. [Ans : 2]

Q.15. 1.      If two zeros of the polynomials   x⁴– 6x³– 26x²+138x -35 are 2- Root3  and 2+ root3 , find all the zeros  .

( Ans. Zeros p(x) are 2 - root3  and 2 + root3 , -5 and 7)

Class X Polynomial Test Paper-1

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Class X Polynomial Test Paper-4

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 10th maths polynomial extra score questions

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 CBSE 10th Chapter 2 Polynomials Test paper

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CBSE class 10 Biology Chapter : control and coordination ---Trend Setter solved Problems

1. How does the nervous tissue cause action? 

Ans:. When a nerve impulse reaches the muscle,the muscle fibre must move by changing their shape.this is
possible as muscle cells have special proteins that change both their shape and arrangement in the cell in response to nervous electrical impulses.when ths happens new arrangements of these proteins give the muscle different shapes.

2.Which organ secretes hormone when the blood sugar rises?name a digestive enzyme released by this organ.

Ans: Pancreas secretes hormone insulin when sugar level rises.Digestive enzyme secreted by pancreas is  trypsin(that digests protein). 

3.What will happen when plant is exposed to unidirectional light?

Ans: .Phototropism i.e. bending of stem towards unidirectional flow of light.

4. A particular hormone requires iodine for its synthesis.Name the endocrine gland which secretes this hormone  and state its location in human body.

Ans: Thyroid gland secretes thyroxin which requires iodine.it is located on the trachea below the voice box.

5.How are our brain and spinal cord protected?
Ans: .Brain –inside bony cage called cranium or skull. Spinal cord—vertebral column.

6.Identify the glands and mention hormones produced .

a. .Gland which prepares our body to function at maximum efficiency during anger or danger.
b. Gland that helps in growth of bones and muscles.
c.  Gland that helps in growth of secondary sexual characters in males.

Ans: 

a.adrenal gland, hormone is adrenaline.
b.pituitary gland, hormone is growth hormone
c.testes,testosterone. 

7.Give reasons: 

(i)why we must take iodised salt?
(ii)why the touch –me-not(Mimosa pudica)plant leaves droop when touched? 

Ans :

 (i) iodized salt contains iodine element which is required for thyroxine hormone,lack of iodine will not help
in production of thyroxine and hence the thyroid gland will enlarge leading to goiter-swelling in neck region.

(ii) Touch-me-not plant cells are filed with water.on being touched at the base of leaf,these cells loose water and become flaccid so they droop .this type of movement is growth independent.

8.What is reflex arc? 

Ans :It is a rapid automatic, unconscious and involuntary response of the body to a stimulus without involving
the brain.

On application of stimulus ---> receptor --->  sensory neuron----> spinal cord---> motor neuron----> effector(muscle and glands). 

Example-salivation of mouth at thought of good food,constriction of pupil in bright light, sneezing, removing
hand on touching hot plate.

9. What are the characteristics of animal hormones?

Ans :

a.They are secreted by endocrine glands directly into the blood.
b.they act away from their site of production. .
c.They are required in small quantity.
d.deficiency or over secretions of hormones have negative effects in the body. 

e.hormones are specific in their action

10.Write the mechanism of adrenaline hormone?  OR Why adrenaline is called emergency hormone? 

Ans : Adrenaline hormone is released into the blood from the adrenal gland during stimulation of the nervous
system on seeing any adverse situation of fight or fright
i) increases the blood pressure
ii) increases heart beat rate
iii) increases breathing rate
iv) diverting blood to essential organs including the heart, brain and skeletal muscles by dilating their blood
vessels and constricting those of less essential organs, such as the skin and digestive system.

11.What is synapse? 

Ans :The functional junction between neurons for the transfer of information i.e. nerve impulse ,occurs from one neuron to the next.

12.What regulates the timing and amount of release of hormones?

Ans :This is regulated by feedback mechanisms for example,glucose level in the blood is maintained constant by either of the feedback mechanisms 

a) high glucose level in the blood induces the pancreatic cells to produce more insulin which converts glucose to glycogen. 

b) less glucose level in the blood does not induce the pancreatic cells to produce insulin so that less conversion of glucose to glycogen may occur.

13.What is the role of Medulla?

Ans. Many of the involuntary actions are controlled by the mid and hind brain. All these involuntary actions like: blood pressure, salivation, and vomiting are controlled by the medulla in the hind brain.

14. What is the function of cerebellum? 

Ans. Activities like: walking in a straight line, riding a bicycle, picking up a pencil( precision of voluntary
actions), maintaining the posture and balance of the body are controlled by cerebellum.

15. What is the function of fore brain? 

Ans. It is the main thinking part of the brain. It has regions to receive sensory impulses from various
Receptors. Separate areas of fore brain are specialized for hearing, smell, sight and so on. The sensation of
feeling full is also controlled by it. 

Further study materials

Quick Revision Notes Ch: Control and  Co - Ordination	Download File
10th Control and coordination solved Questions	Download File
10th Chapter How do we Reproduce E notes	Download File
10th Control and coordination NCERT solution	Download File

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CBSE TEST PAPER-01  SCIENCE & TECHNOLOGY (Class-10)    Chapter 6 : Life Process

1. What are the raw materials for photosynthesis? (1 mark)

Answer: The raw materials and other necessary items required for photosynthesis are Sunlight, Water, CO₂ and Chlorophyll.

2. What is the role of bile juice in digestion? (1 mark)

Answer: Bile is alkaline in nature and it is temporarily stored in gall bladder and helps in digestion of fats,

it also helps in absorption fats.

3. Write the equation for respiration? (1 mark)

Answer:

	Glycol sis		In presence of O2
C6H12O6	------->	C3H4O3	---------------->	6CO2 +	6H2O   +	38ATP
		Pyruvic acid	Kreb cycle in mitochondria

4. Name three types of blood vessels used in the transport of blood. (1 mark)

Answer: Arteries, vein and capillaries

Note: There are three major types of blood vessels: the arteries, which carry the blood away from the heart; the capillaries, which enable the actual exchange of water and chemicals between the blood and the tissues; and the veins, which carry blood from the capillaries back toward the heart.

5. Name the artificial method for the removal of liquid nitrogenous waste from body? (1 mark)

Answer: Dialysis: Dialysis is a process by which waste materials and excess water are removed from the blood. This is a normal function of our kidneys inside the body. 

6. Write any two points of difference respiration in plants and respiration in animals. (2 marks)

Answer: 

Respiration in plants.	Respiration in animals
1.In plants separate respiratory organs are absent	1.In animals respiratory organs are generally present
2.The rate of respiration is slow.	2.The rate of respiration is fast.
3.They lack respiratory surface	3. Respiratory surface is generally present.

7. Draw the labelled diagram of the human respiratory system. (2 marks)

Answer:  

8. How are the alveoli designed to maximize the exchange of gases? (2 marks)

Answer: The alveoli are present at the terminal of bronchioles. They are balloon shaped structures which increases the surface area for the exchange of gases and are richly supplied with blood vessels to take the oxygen to different cells

9. Amylase is secreted by two different glands. Name them. Write is the action of amylase on food? (2 marks)

Answer: Salivary glands are found in mouth cavity .They secrete enzyme called salivary amylase or ptyalin. It helps in digestion of starch.

Pancreas secrets pancreatic juice into small intestine. Pancreatic juice contains tyrosine and pancreatic amylase.

Pancreatic amylase is a major digestive enzyme, which can hydrolyze starch into simpler sugars, like maltose and glucose, for absorption.

10. Name the passage in sequence through which urine passes from kidneys to the outside in humans. How is urine prevented from flowing back into the ureters? (2 marks)

Answer:  

kidney ->  the urinary bladder -> the urethra ----> outside [via vaginal opening in women or via the penis in man]

There are valves present in ureters called as ureterovesical valves which prevent the backflow of urine.

11. State the role of the following in the human respiratory system

(i) Nasal cavity (ii) Diaphragm (iii) Alveoli (3 marks)

Answer: (i) Nasal cavity: It contains hair and mucus which entrap the dust particles.

 (ii) Diaphragm: Contract and relax to increase  and decrease the  volume of chest cavity respectively

(iii) Alveoli: it helps in exchange of air in blood. it transfer oxygen to the blood and takes carbon di oxide from the blood.

12. Give reasons for the following:

(i)The glottis is guarded by epiglottis.

(ii) The lung alveoli are covered with blood capillaries.

(iii) The wall of trachea is supported by cartilage rings. (3 marks)

Answer : (i) The epiglottis guards the entrance of the glottis and prevent flow of food into wind pipe.

(ii) Lungs alveoli are covered with blood capillaries for the exchange of gases to take place and oxygen can easily diffuse into the blood stream and be transported to various parts of the body through the heart.

(iii)   The wall of trachea is supported by cartilage rings which percent them to collapse when air is absent in them

13. Leaves of a healthy potted plant were coated with Vaseline to block the stomata. Will this plant remain healthy for long?  State three reasons for your answer. (3 marks)

Answer: By applying Vaseline on leaves stomata gets covered and transpiration stops. This prevents loss of water vapour and the moisture of the leaf retain for sometimes. But as the layer of vaselin stops all type of gaseous exchange, leaf will end up dying.

(a) Respiration will stop. (b) Transpiration will stop. (c) Photosynthesis will stop.

14. What are the differences between aerobic and anaerobic respiration? Name some organisms that use the anaerobic mode of respiration. (3 marks)

Answer :

Aerobic	Anaerobic
(i) It occurs in all living cells of higher plants.	It occurs in bacteria, certain fungi, germinatin seeds and fleshy fruits muscles.
(ii) It requires oxygen.	Oxygen in not required
(iii) The end products are CO2 and H2O.	The end products are alcohol [fungi] or lactic acid [ muscles] and CO2.
(iv) The oxidation of one molecules of glucose produces 38 ATP molecules	The number of ATP molecules produced is only 2.
some organisms that use the anaerobic mode of respiration : bacteria, certain fungi, germinatin seeds and fleshy fruits muscles

15. Describe double circulation in human beings. Why is it necessary? (3 marks)

Answer :The blood passes to aorta from the left ventricle. The aorta gives rise to many arteries that distribute the oxygenated blood to all the regions of the body.Therefore, the blood goes twice through the heart. This is known as double circulation.

Importance of double circulation:: This separate oxygenated and deoxygenated blood that ensure more efficient supply of oxygen to the body cells. This also help in maintaining a constant internal temperature and allows mammals and birds to carry-out body processes more efficiently.

16. (i) Name the blood vessel that brings oxygenated blood to the human heart. (5 marks)

(ii) Which chamber of human heart receives oxygenated blood?

(iii) Explain how oxygenated blood from this chamber is sent to all parts of the body.

Ans: (i) The pulmonary vein (ii) the left atrium

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As CBSE Class 10th Social Science exam approaches studying strategies are needed more than ever. Social Science is thought of as one of the most boring subjects. While in class X the benefits of studying social sciences may not be apparent to you, rest assured there are definitely many benefits. History, Geography, Political Science and Economics, whichever may be your most favorite or least favored, the time has come to study! Here are some tips!

 

Syllabus:

Term II

-India and the Contemporary World II (History) 23 marks

Nationalism in Europe 

Nationalist Movement in Indo China

Nationalism in India

Map work

-India - Resources and their Development (Geography) 23 marks

Mineral Resources

Power Resources

Manufacturing Industries

Transport, communication and trade

Map Work (3 marks)

-Democratic Politics II (Political Science) 22 marks

Competition and contestations in Democracy

Outcomes of Democracy

Challenges to Democracy

-Understanding Economic Development II (Economics) 22 marks

Money and Credit

Globalization

Consumer Awareness

Total marks: 90

TIPS:

-Read the course once without trying to remember it, just read like you would read the newspaper and try to understand it

-Prioritize your subjects and topics according to marks weight-age and easy and difficult chapters, use this list to create a practical study schedule

-Take notes for specific points you feel are important and you are likely to forget, in addition to school notes

-Create a chart with important dates, flip through it often and you will find that you are able to easily remember the dates

-Study subject-wise rather than from all topics combined; they were separated for a reason

-Use flash cards for definitions

-Also make flash cards for various history events; flash cards help for fun and quick revision

-Practice map work by tracing the important locations you want to remember, then try locating on a blank map

-Understand economics and political science, its better than to try to memorize

-Solve previous year papers/ sample papers to practice writing within word limits 

-Keep at least one month for revision

-Use mnemonics to remember details

Although social science may seem dull, use study tools to make it fun. Flash cards, timelines, colorful charts and funny mnemonics can help you study in addition to textbook and notes reading. In 10th class either your social sciences studies are beginning or ending, in any case happy studying and all the best!

CBSE SST Trend setter Study materials

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CBSE ADDA CBSE TEST PAPER-03
SCIENCE & TECHNOLOGY (Class-10) Chapter 6 : Life Process

1. What are the raw materials for photosynthesis? (1 mark)

Answer: The raw materials and other necessary items required for photosynthesis are Sunlight, Water, CO₂and Chlorophyll.

2. Give the energy transformation that takes place in the process of photosynthesis. (1 mark)

Ans: Light energy converted into chemical energy

3. Write the equation of photosynthesis. (1 mark)

Ans:

			Sunlight
6CO2	+	12H2O	----------->	C6H12O6	+	6O2	+	6H2O
			chlorophyll

4. What is the respiratory organ of earthworm? (1 mark)

Ans: Gaseous exchange occurs through moist skinby diffusion

5. Give the function of xylem. (1 mark)

Ans:  Transport water and mineral to green leaves

6. Write any two functions of large intestine to man. (2 marks)

Ans(a)  Inner lining of colon has numbers of villi  that absorb water from undigested food and form solid waste

(b) Store solid secrete in rectum and spell out with anus

 7. How are lungs designed in human beings to maximize the area for exchange of gases (2 marks)

Ans:  The lungs get filled up with air during the process of inhalation as ribs are lifted up and diaphragm is flattened. The air that is rushed inside the lungs fills the numerous alveoli present in the lungs.

These numerous alveoli increase the surface area for gaseous exchange making the process of respiration more efficient.

8. Draw the human heart and label its parts. (2 marks)

Ans:  See NCERT Figure 6.10 -Sectional view of the human heart

9. Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like human? (2 marks)

Ans:  Diffusion is insufficient to meet the energy requirements of large multicellular organisms like humans because the volume of the human body is so big that oxygenthe diffusion pressure alone cannot take care of oxygen delivery to all parts of the body. This is because oxygen has to travel large distances inside the body to reach each and every cell quickly but diffusion is a very slow process.

10. What is the role of the acid in our stomach? (2 marks)

Ans:  The hydrochloric acid creates an acidic medium which facilitates the action of the enzyme pepsin and also kills bacteria present in food.

11. Draw a diagram & describe the process by which excretion occurs in amoeba. (3 marks)

Ans:  Amoeba removes these wastes by simple diffusion from the body surface into the surrounding water.

[Amoeba is an ammonotelic organism since the principal excretory product is ammonia. Special excretory organelle in Amoeba is lacking. CO2 and ammonia are exerted by diffusing is solution through plasma membrane. The concentration of ammonia is always higher in Amoeba than in the surrounding water. The water enters through plasma membrane by “endosmosis”. Ammonia is formed in cytoplasm by metabolism. Surplus water enters contractile vacuole. This surplus water can rupture the animal’s body. Thus size of contractile vacuole increases, when the contractile vacuole is fully expanded with water, it moves towards the periphery. As it comes in close contact with the plasma membrane, the contractile vacuole bursts. Thus excess of water (surplus water) is discharged in the surrounding water, this phenomenon of controlling the amount of water in the body is called as “osmoregulation”. ]

12. How does blood circulate between lungs and heart in human beings? Give two functions of lymph in human body. (3 marks)

Ans: At first the impure blood from all the body parts reach the right auricle and then into right ventricle.From right ventricle it is carried to lungs through Pulmonary arteries .In lungs, it gets purified [alveoli do the purification] and then it is send  to left auricle through Pulmonary Vein. From left auricle it flows into left ventricle and then to all the body parts through systemic aorta.

Lymph carries digested and absorbed fat from intestine and drains excess fluid from extra cellular space back into the blood.

13. How do each of the following factors affect the productivity in the process of photosynthesis?
(i) Temperature   (ii) Water   (iii) Carbon dioxide.   (3 marks)

Ans:  (i) Temperature   : The higher the temperature then typically the greater the rate of photosynthesis, photosynthesis is a chemical reaction and the rate of most chemical reactions increases with temperature

(ii) Water   :  An increase in the amount of water leads to the increase in the amount of photosynthesis.

The amount of water available to the plant will affect the rate of photosynthesis. If the plant does not have enough water, the plant’s stomata will shut and the plant will be deprived of CO₂, and thus lower photosynthesis rate .

(iii) Carbon dioxide. The concentration of carbon dioxide in the Earth’s atmosphere varies between 0.03% and 0.04%. An increase in the concentration of carbon dioxide gives an increase in the rate of photosynthesis.

14. Write necessary conditions for autotrophic nutrition and its by-products? (3 marks)

Ans: The necessary conditions for autotrophic nutrition are :

1. Sunlight   2.water 3.CO2     4.chlorophyll;   It’s by-products are  carbohydrates & oxygen

15. How are fats digested in our body? Where does this process take place? (3 marks)

Ans:  Fats are present in the form of large globules in the small intestine. The small intestine gets the secretions in the form of bile juice and pancreatic juice respectively from the liver and the pancreas. The bile salts (from the liver) break down the large fat globules into smaller globules so that the pancreatic enzymes can easily act on them. This is referred to as emulsification of fats. It takes place in the small intestine.

16. (i) Draw a labeled diagram of the respiratory system of human beings with diaphragm at the end of expiration. (5 marks)
(ii) List four conditions required for efficient gas exchange in an organism

Ans: 

(ii) (a)A large surface area over which exchange can take place.

(b) A concentration gradient without which nothing will diffuse.

(c) A thin surface across which gases diffuse.

(d) Warm conditions

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Trend setter CBSE TEST PAPER-02

SCIENCE & TECHNOLOGY (Class-10) Chapter 6 : Life Process

1. Point out of differences between an artery and vein. (1 mark)

Ans: Any one:

Artery

1. Vessels which carry blood from the heart to various body parts

2. Arteries carry oxygenated blood from the heart except pulmonary artery

3. Arteries have thick elastic muscular walls

4. Valves are absent

5. Blood flows under high pressure

Vein

1. Vessels which carry blood from the various body parts to the heart

2. Veins carry deoxygenated blood from the various body parts except pulmonary vein

3. Veins have thin non elastic walls

4. Valves are present to prevent the backward flow of blood

5. Blood flows under low pressure

2. Write the two functions of kidneys. 

Ans.  Osmoregulation and excretion.

3. Name the largest artery in human body. (1 mark)

Ans: The largest artery in the human body is the aorta. It carries oxygenated blood to the whole body from the heart.

4. What is the difference between stroma and grana? (2 marks)

Ans:

Grana	Stroma
The stacks of thylakoids are called grana.	Grana are connected by intergrana or stroma thylakoids
Grana contribute to chloroplasts' large surface area to volume ratio.	It carries all the enzymes, e.g., RUBISCO, needed to carry out the "dark" reactions of photosynthesis

5. Write two differences between the transport of materials in xylem and phloem. (2 marks)

Ans: 

Xylem	Phloem
(i) Functional xylem ells are dead.	(i) Functional phloem cells are alive.
(ii) It carries mineral salts, water and traces of organic molecules	(ii) An organic solution of sugars and amino acids is translocated.
(iii) The movement is only upward.	(iii) The movement can be upward or downward.

6. What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration? (2 marks)

Ans: In the aquatic habitat the concentration of oxygen is good up to a certain depth only. Moreover, as oxygen is available as dissolved in water, so taking oxygen from there is not a very efficient method to that.

In terrestrial habitat oxygen is available in free form so it is easier to absorb by organisms. This is more efficient so terrestrial organisms can facilitate better utilization of food by way of respiration.

7. Differentiate between osmoregulation and excretion?

Ans: Excretion is the elimination of metabolic waste  products from the body.

Osmoregulation is regulating osmotic pressure of the body fluids by controlling the amount of water and salts in the body

8. Name any two autotrophic plants which also show heterotrophic mode of nutrition. Why do they need to do so? (2 marks)

Ans: All green plants are autotrophic but some of them also show heterotrophic nutrition like Venus fly trap and pitcher plant as their nutritional requirement is not fulfilled by photosynthesis like nitrogen and phosphorus as in some areas, the soil is deficient in nitrogen.

9. Name 3 kinds of blood vessels of human circulatory system. Write function of each. (3 marks)

Ans:

	Arteries	Veins	Capillaries
1.	Carry Oxygen rich blood from heart to all parts of the body.	Carry carbon dioxide rich blood from all parts of the body back to the heart.	Capillaries act as a link between arteries and veins.
2.	Since blood flow is rapid and at high pressure they have thick elastic walls.	They have thin walls	Consists of just a single layer of endothelial cells.  Water and other small-molecule substances can pass through this wall.
3.	Valves are absent.	Valves present to prevent back flow of blood.	No valves are found

10. Name the constituents of blood. Why are WBC called ‘soldiers of the body’? (3 marks)

Ans: The constituents of blood are

1. Red blood cells or RBCs (erythrocytes)

 2. White blood cells or WBCs (leucocytes)

 3. Blood platelets (thrombocytes)

WBC is called ‘soldiers of the body’ because

(a) White blood cells protect the body from infec on. If germs like bacteria or viruses enter the body, these cells surround the germs and destroy them by digesting.

 (b) They also produce an bodies (blood proteins) which kill the germs and foreign particles entering our body.

11. Explain the process by which inhalation occurs during breathing in human beings. (3 marks)

Ans: he process by which oxygen rich air is taken up through the nostril into the body is known as inhalation. During inhalation, the chest cavity increases in size due to the downward movement of the diaphragm (dome shaped muscular sheet that separates chest from abdomen). As a result air from outside rushes into the lungs to fill the extra space.

Exhalation is the process by which carbon dioxide rich air comes out of the body. It occurs when the diaphragm moves up and the chest cavity becomes narrower. This creates a pressure on the air inside the lungs. As a result the air comes out of the lungs to the atmosphere due to lack of space inside. Both the process of inhalation and exhalation is commonly known as breathing.

12. Compare the functioning of alveoli in the lungs and nephrons in the kidneys with respect to their structure and functioning. (3 marks)

Ans:

Alveoli	Nephron
Structure	Structure
(i) Alveoli are tiny balloon-like structures present inside the lungs.	(i) Nephrons are tubular structures present inside the kidneys.
(ii) The walls of the alveoli are one cell thick and it contains an extensive network of blood capillaries.	(ii) Nephrons are made of glomerulus, bowman’s capsule, and a long renal tube. It also contains a cluster of thin-walled capillaries.
Function	Function
(i) The exchange of O 2 and CO2 takes place between the blood of the capillaries that surround the alveoli and the gases present in the alveoli.	(i) The blood enters the kidneys through the renal artery which branches into many capillaries in the glomerulus. The water and solute are transferred to the nephron at Bowman’s capsule. Then the filtrate moves through the proximal tubule and then down into the loop of henle. From henle’s loop, filtrate passes into the distal tubule and then to the collecting duct. The collecting duct collects the urine from many nephrons and passes it to the ureter. During the flow of filtrate, some substances such as glucose, amino acids, and water are selectively re-absorbed.
(ii) Alveoli are the site of gaseous exchange.	(ii) Nephrons are the basic filtration unit.

13. Draw a diagram of human alimentary canal showing duodenum, small intestine, liver and pancreas. (3 marks)

OR

State the two vital function of the human kidney.

Name the procedure used in the working of artificial kidney. (3marks)

Ans: (a) Function of Kidneys:

• Absorption of water and salt
• Removal of waste materials like urea, ammonia etc from blood
• Blood pressure control

  (b) Artificial kidney works on the principal of dialysis. It is also known as haemodialysis.

In hemodialysis, only a few drops of blood are allowed to flow, through a special filter that removes wastes and extra fluid. The detoxified blood is then returned to the body.

The special filter used in dialysis consists of a number of tubes with semi-permeable lining, suspended in a tank filled with the dialysis fluid.

14. What are the methods used by plants to get rid of excretory products? (5 marks)

Ans:

Plants get rid of carbon dioxide and oxygen through diffusion. Old branches and leaves are shed off when they become useless. Plants release some waste products through roots also. Some waste products are deposited near bark as raisins or gums.

15. (i) State two structural differences between an artery and a vein. (5 marks)

(ii) Name a non-nucleated cell present in human blood and state one functions of this cell.

Ans: RBC. Their chief function is to transport oxygen to different parts of the bod

(iii) Draw a labelled diagram of human heart.

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