Science of S.S.C

8/14/2019 Science of S.S.C

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ROME WAS NOT BUILD IN A DAY

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INDEX

CHAPTER NAME NO

1. FUELS

2. HEAT

3. MODERN PHYSISCS

1. DIETARY DEFICIENCY DISEASES

2. DISEASES DUE TO OVERINTAKE OF SOME NUTRIENTS.

3. FOOD WASTAGE

4. FACTORS CAUSING FOOD SPOILAGE

5. HUMAN HEALTH AND DISEASES

6. BIOSPHERE

7. BIOGEOCHEMICAL CYCLES

8. RECYCLING OF WASTE MATERIALS

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16

21

28

36

40

46

53

61

66

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FUELSQ1. Define 1. Radioactivity:- The phenomenon of spontaneous and continuous emission of

radiation from certain heavy element is called radioactivity.2. Radioactive substance:- The substance, which spontaneously andcontinuously emits certain radiations is called a radioactive substance.3. Fission products:- The products formed during a nuclear fission are calledfission products.4. Controlled chain reaction:- The process in which most of the neutronsliberated in the chain reaction are absorbed and only a few neutrons are allowedto carry on the reaction is called controlled chain reaction.5. Un controlled chain reaction:- The self accelerating chain reaction whichtakes place on its own around is called uncontrolled chain reaction.6. Calorific value:- The quantity of heat produced by the complete combustion

of unit mass of a fuel is called the calorific value of the fuel.7. Disintegration of radioactive elements:- The process of continuous andspontaneous emission of radiations from a radioactive element to form a newelement continues till a non radioactive element is formed is calleddisintegration or decay of radioactive elements.8. Nuclear wastes:- The harmful radioactive waste are produced by mining intoenrichment and use in the nuclear reactors is known as nuclear wastes.

Q2. Give scientific reasons:-

1. Boron steel or cadmium rods are used to control chain reaction

Ans.1. Boron steel or cadmium rods have a property of absorbing neutrons.2. The rate of chain reaction can be reduced by absorbing some of neutronswhich is generated, therefore boron steel or cadmium rods are used to controlchain reaction.

2. The elements having atomic number greater than 82 are radioactiveAns. The nuclei of elements having atomic number greater than 82 are unstable.Hence, the elements having atomic number greater than 82 are radioactive.

3. Water gas is called blue gas.Ans. Water gas burns with bluish flame. Hence water gas is called blue gas.

4. Coal is fossil fuel.Ans. Coal is formed form the remains of plants and animals buried under theground million of years back. Such remains are called fossils. Hence, coal isfossil fuel.


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FUELS5. A nuclear reactor has thicker cover. (or)

A thick coat of radiation absorbent materials is used around theatomic reactor.

Ans.1. Nuclear energy production in an atomic reactor is accompanied by releaseof radioactive pollutants and harmful radiations

2. These pollutants also produce harmful radiation, which are highlypenetrating.

3. This radiations cause irreparable damage to the body cells. They causehereditary changes.

4. This radiations should be prevented from leaking out. Hence, a nuclear reactor has a thicker cover.

6. Coke produces more heat than coal. (or)

Coke is a superior fuel than wood and coal.Ans.1. The calorific value of a fuel depends upon its carbon content.2. Coke contains about 90 95% carbon.3. The main combustible components of wood is cellulose, which is a

carbonaceous substance.4. Coal contains 10 80% carbon depending upon the type of coal. Hence,

coke produces more heat than coal.

7. Hydrogen is not used as domestic fuel, even though it has high calorificvalue.

Ans.1. Hydrogen gas us explosive.2. It forms explosive mixture with air. It is very difficult to handle hydrogen.Hence, hydrogen is not used as domestic fuel, even though it has high calorificvalue.

8. In the manufacture of ammonia producer gas is used.Ans.1. Ammonia is the mixture of nitrogen and hydrogen in a suitable proportion.2. In the producer gas, the percentage of nitrogen is 60%. Hence, the producer gas is used in manufacture of ammonia.


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FUELS9. Petroleum is a fossil fuel.Ans.1. Petroleum is formed from the remains of micro organisms living under the

sea.2. When these organisms die, they sunk to the bottom of the sea and aregradually covered by sand and clay.3. Due to the action of heat, pressure and certain catalytic actions taking placeover millions of years, these remains are converted into a mixture of hydrocarbons called petroleum. Such remains are called fossil fuels. Hence,petroleum is a fossil fuel.

10. Gaseous fuels are superior to the solid and liquid fuels.Ans.1. They are extremely clean and convenient to use.

2. The burn almost instantaneously to provide heat energy.3. The combustion of gaseous fuels can be easily controlled.4. They have high calorific value.5. They do not produce any solid waste products.6. They can be transported easily and can be supplied through pipes at anydistant place. Hence, Gaseous fuels are superior to the solid and liquid fuels.

11. Wood is a fuel.Ans.1. A substance which on combustion produces heat, which can be used for various purposes, is called a fuel.

2. The main combustible component of wood is cellulose, which is acarbonaceous substance.3. It burns in air forming carbon dioxide, water vapour and generate heat, hence,wood is a fuel.

12. Combustion of methane produces a large amount of heat.Ans.1. Methane is a hydrocarbon.2. The carbon atom in methane is bonded to four hydrogen atoms.3. On combustion with oxygen in air, it forms carbon dioxide and water vapour and generate heat. Hence, wood is a fuel.


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FUELS13. L.P.G is an ideal fuel.Ans.1. L.P.G is liquefied petroleum gas. It contains butane and isobutene. The mixture

is liquefied and filled in cylinders.2. Hence, it is easy to handle and transport.3. When the valve of the cylinder is opened the gaseous state and can be burnedin the stove. Thus the supply of the gas can be controlled. Hence, L.P>G is anideal fuel.

14. Conservation of fuels is essential.Ans.1. The energy obtained from fuels is used for cooking food, driving engines andvehicles, getting light, and for industries. In the world industrialization isadvancing fast. The urbanization is also very fast. For big cities and for the

industries large amounts of fuels are required.2. Currently 80% of the energy consumed in the world is obtained by burningcarbon fuels or fossil fuels.3. The reserves of these fuels are limited and getting exhausted very fast. Hence,conservation of fuels is essential.

15. The calorific value of water gas is greater than that of producer gas.Ans.1. Water gas contains carbon monoxide (45%), hydrogen (45%) and other gases(10%). Producer gas contains carbon monoxide (30%), nitrogen (60%), and other gases (10%).

2. In water gas both the components are combustible.3. In producer gas carbon monoxide is combustible, but nitrogen is non combustible. The percentage of carbon monoxide in producer gas is lower thanthat in water gas. Hence, the calorific value of water gas is greater than that of producer gas.

16. In future, factories may be run with nuclear energy.Ans.1. All factories require fuels for various operations.2. Presently about 80% of the energy consumed is obtained by burning fossilfuels.3. The reserves of fossil fuels are limited. They are getting depleted very fast.4. Atomic nuclei are vast store of energy. Nuclear fission produces a largeamount of energy from a very small mass of U 235. This energy can beconverted into other suitable forms of energy like electricity. Thus, this source of energy can sustain for a much longer time. Hence, in future, factories may be runwith nuclear energy.


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FUELSQ3. Answer the following:-

1. What is a fuel?

Ans. The substance which on combustion produce energy in the form of heat,which can be used for various processes is called a fuel.

2. How are fuels classified? Explain with examples.Ans. Fuels are classified as solid, liquid and gaseous fuels.

Solid fuels --------- Wood, coal, coke etc.Liquid fuels --------- Petrol, Kerosene, fuel oil etc.Gaseous fuels -------- Natural gas, petroleum gas, water gas etc.

3 Give characteristic of an ideal fuel.Ans.

1. Ideal fuels should have high calorific value.2. It should have low content of non combustible material.3. It should have moderate rate of combustion.4. It should have definite ignition temperature.5. Absence of poisonous products on combustion.6. It should be available in large quantities at a cheaper rate.7. It should be easy to store, transport and handle.

4. Write short note on calorific value?Ans.

1. The quantity of heal produced by a unit mass of fuel after combustion is

called calorific value of the fuel.2. It is expressed in calories/ gm in C.G.S and Joule / Kg in S.I. units.3. The calorific value of gaseous fuel is the quantity of heat produced by

complete combustion of unit volume of the fuel.4. Charcoal 33 Kj/g, Kerosene 48 Kj/ g, L.P.G 55 Kj/ G and biogas 35

40 Kj/ g.

5. Outline the used of atomic energy.Ans. The uses of atomic energy are as follows.

1. Atomic energy is used to generate electricity.2. It is used to power submarines.3. It is used to make atom bombs.


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FUELS6. What are the effects of an explosion of an atom bomb?Ans.

1. The principle of uncontrolled chain reaction of U 235 is used in atom

bomb.2. When it is exploded huge amount of energy and radiation s are emitted inshort time.

3. AT place of explosions temperature shoots upto a few million degreeCelsius.

4. The energy produced under pressure is equal to several timesatmospheric pressure.

5. The high temperature, high pressure and harmful intense radiation destroyall animals and plants in the surrounding area.

7. Write a brief account of emission, which is harmful to living organisms?

Ans. Nuclear fission by products are formed in nuclear explosions and innuclear reactors. These by products emit beta as well as more penetratinggamma radiations. When a human body is exposed to these radiations in a largedense, the body cells suffer irreparable damages. These radiations can inducesome hereditary changes and thereby affect future generations too.

8. How is petroleum formed?Ans.

1. Petroleum is formed from the microorganisms living under the sea.2. When these organisms die, they sink to the bottom and are gradually

covered by sand and clay.

3. These remains are converted into hydrocarbons due to the action of heat,pressure and certain catalytic actions taking place over millions of years.4. The resulting mixture of hydrocarbons rises through the porous rocks till it

meets impermeable rocks. There it forms an oil trap.

9. How is petroleum obtained?Ans.

1. Petroleum reservoirs are located through a geological survey.2. A hole is then drilled through the impervious rock, to the petroleum trap.3. A pipe is introduced to the petroleum trap through this hole. Petroleum

rises to the surface through this pipe.

10. What is L.P.G? From what source is L.P.G. obtained?Ans. L.P.G is liquefied petroleum gas. L.P.G is obtained by cooling natural gasand fractional distilling the liquid. It can also be obtained by the fractionaldistillation of petroleum.


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FUELS11. What are the safety precautions to be taken while handling gaseousfuels? Why?Ans.

1. All gaseous fuels are readily combustible.2. They may contain carbon monoxide, which is poisonous.3. If a gaseous fuel contains hydrogen, we have to be very careful, as

hydrogen forms an explosive mixture with air.4. An explosion may occur if such a gas leaks and there is an accidental

sparking or lighting of a match. Hence, it is essential that there should notbe any leakage of a gaseous fuel. When the gas is not required, it shouldbe completely turned off.

12. What precautions one should take while handling L.P.G safely?Ans. While handling L.P.G following precautions should be taken

1. The gas should be turn off by closing the valve when the gas is notrequired.2. If L.P.G leaks out of the cylinder no matchstick should be struck in the

house or any spark is allowed to strike.3. The cylinder should be kept away from heat in a secured place.

13. Why is energy liberated in a nuclear fission process? (Or)Write Einsteins equations for the energy liberated in a nuclear fission andexplain it (Or)Give the relation between mass lost and the energy liberated during anuclear fission reaction. Explain the terms involved.

Ans. In a nuclear fission process, the mass of the original nucleus is alwaysgreater than the total mass of the fission products. The difference in the mass isconverted into energy, according to Einsteins equations.

E = mc 2 Where E = energy released, m = Loss in mass, c = speed of light in vacuum.


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FUELSQ4. Write short notes on

1. Coal

Ans.1. Coal is fossil fuels. It has been formed over millions of years by the burialof plants.

2. Coal contains free amorphous carbon and complex carbon compoundsformed from the parent plant matter.

3. Coal is classified into four types on the basis of its free carbon content.i. Peat (11%)ii. lignite (22%)iii. Bituminous(60%)iv. Anthracite (80%)

4. Destructive distillation of coal gives coke, coal, tar and coal gas.

2. CokeAns.

1. Coke is obtained when coal is heated in the absence of air.2. Coke contains about 90 -95% carbon. It does not contain any volatile

matter.3. It is hard and burns without producing smoke. It produces more heat than

coal.

3. PetroleumAns.

1. The dark oily liquid formed from the microorganism living under the seaand which occurs in the pores of sedimentary rocks is called petroleum.2. It is a complex mixture of hydrocarbons.3. It is formed from the remains of microorganisms due to the action of high

pressure, heat and certain catalytic action over a period of millions of years.

4. On fractional distillation, petroleum gives useful products like, fuel oil,diesel, kerosene, petrol and petroleum gas.

4. Natural gasAns.

1. The gas, which is found in the form of underground reservoirs in theregion of coal and petroleum oil is called natural gas.

2. It contains hydrocarbons: methane (80 90%), ethane (6 10%),Propane (3 5%) and butane ( 1 2%)

3. Butanes (L.P.G) and other gases can be separated by cooling the naturalgas and fractionally distilling the liquid.


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FUELS 5. L.P.G.Ans.

1. L.P.G is liquefied petroleum gas.2. It mainly contains liquefied butane and isobutene.3. It is obtained by cooling natural gas and fractionally distilling the liquid or

by the fractional distillation of petroleum.4. It is supplied in steel cylinders for cooking or industrial use.

6. Fossil fuelsAns.

1. Fossil fuels are formed over millions for years by the burial of plants andanimals.

2. They contain energy rich molecules of carbon compounds originally made

by plants.3. Coal, petroleum and natural gas are examples of fossil fuels. About 80%of the energy consumed in the world is obtained by burning these fuels.

7. Fractional distillation of petroleum.Ans.

1. Petroleum or crude oil is brown black liquid. Petroleum is a mixture of several hydrocarbons.

2. When it is distilled, it separates into various fractions of hydrocarbons.3. The compounds obtained from fractional distillation of petroleum which are

useful as fuels are fuel oil, diesel, kerosene, petrol and petroleum gas.

8. Liquid fuels.Ans.

1. Liquid fuels are hydrocarbons.2. Various hydrocarbons are present in petroleum.3. When petroleum is fractionally distilled, it separates into various fractions

of hydrocarbons.4. The fractional distillation of petroleum yields three liquid fuels: gasoline or

petrol, kerosene and fuel oil. Gasoline or petrol is used as motor fuel,kerosene as a domestic fuel and fuel oil is used for oil furnaces.

9. Water gasAns.

1. Water gas is prepared by passing steam over while hot coke at about1400 0 C.

2. It contains carbon monoxide (45%), hydrogen (45%) and other gases(10%)

3. It is used as a fuel and also a source of hydrogen.


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FUELS16. Nuclear reactor.Ans.

1. Uranium 235 is used as a fuel in a nuclear reactor.

2. The nuclear fission of U 235 is carried out by bombarding it with slowneutrons.3. Boron steel or cadmium rods control the nuclear chain reaction set in.

Thus, the liberation of energy in the fission process is controlled.4. The energy released is used to vaporize water and the steam formed is

used to run turbines. Thus, electricity is generated. Useful radioactiveisotopes are also produced in a nuclear reactor.

Q5. Distinguish between1. Controlled chain reaction and uncontrolled chain reaction.

2. Producer gas and Water gas


Controlled Chain Reaction Uncontrolled Chain Reaction1. The chain reaction in which most of the neutrons are absorbed in called acontrolled chain reaction.2. In this reaction most of theneutrons are absorbed using boronsteel or cadmium rods.3. This reaction is used for peacefulpurposes, like generating electricity.

1. The self accelerating chain reaction,which takes place on its own, is called anuncontrolled chain reaction.2. In this reaction neutrons are notabsorbed.3. This reaction leads to an explosion andhence is used for destructive purposes.

Producer Gas Water Gas1. Producer gas is prepared by passinginsufficient quantity of air through red hotcoal.2. It contains mainly CO and N 2.3. It is used as a fuel and as illuminatinggas.

1. Water gas is prepared over whitehot coke at about 1400 0 C.2. It contains CO and H 2.3. It is used as a fuel in glassfurnace and metallurgical furnaces.

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FUELS3. Solid Fuels and Gaseous Fuels.

4. Coal and Coke


Solid fuels Gaseous fuels

1. The calorific value of solid fuels islower than that of gaseous fuels.2. These fuels are difficult to transport.3. Solid fuels contain some amount of non combustible material.4. They do not burn quickly.5. They produce solid waster products.

1. The calorific value of gaseous fuels ishigher than solid fuels.2. These fuels can be transported easily.3. Gaseous fuels do not contain non combustible material.4. They burn instaneously and their combustion can be controlled easily.5. They do not produce any solidproducts.

Coal Coke1. Coal is a fossil fuel formed by the burialof plants.2. It contains free amorphous carbon andcomplex carbon compounds.3. It contains some volatile matter.4. It burns with smoke.5. It produces less heat than coke.

1. Coke is obtained by thedestructive distillation of coal.2. It contains about 90 95%carbon.3. It does not contain any volatilematter.4. It burns without producing smoke.5. It produces more heat than coal.

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HEATQ1. Define the following

1. Kilocalorie:- Kilocalorie is the quantity of heat required to raise the

temperature of 1 kg of water through 10

C. from 14.50

C to 15.50

C.2. Specific Heat Capacity:- The specific heat capacity of substance is definedas the quantity of heat required to raise the temperature of unit mass of thesubstance through 1 0C.3. Dew Point:- The temperature at which air becomes saturated with water vapour is called dew point.4. Absolute humidity:- The mass of water vapour present in one cubic meter of air is called absolute humidity.5. Principle of heat exchange:- If the system of two bodies is kept isolatedfrom the surrounding so that no heat enters or leaves the systems, then

Heat lost by hot body = Heat gained by cold body.

6. Relative humidity:- Relative humidity is the ratio of actual mass of water vapour present in a given volume of air to the mass of water vapour required tosaturated the same volume at the same temperature.7. Unit of specific heat capacity:- In M.K.S = K cal / kg 0C, in C.G.S = cal /g 0C.


1. If a piece of ice is dropped into a glass of water, it floats on the surface of the water.Ans.

1. Ice is the solid form of water but is density is much less than that of water.2. We know as water cools below 4 0 C its volume increases.3. As a results density of ice is less that that of water and so it floats on thesurface of the water.

2. In winter the pipeline carrying, water burst in cold countries.Ans.1. In cold countries during winter, the temperature of the atmosphere fall below 0 0

C.2. When the temperature of water falls below 4 0 C, it expands. Hence, the water in pipes freezes and expands. As there is no room for expansion, water exerts alarge pressure on the pipes. Hence, the pipes sometimes burst.


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HEAT3. In cold countries during winter even through the lakes are frozen, fishand other aquatic animals and plants can survive in it.Ans.

1.In cold countries, during winter, the temperature of the atmosphere fallswell below 0 0 C.

2. As the temperature decreases, the water at the surfaces of lakes andponds starts contracting.

3. Hence, its density increases and it sinks to the bottom. This processcontinues till the temperature of all the water in the lake falls to 4 0 C.

4. As the water at the surface cools further, its temperature falls below 4 0 C, itstarts expanding instead of contracting.

5. Therefore, its density decreases and it remains at the surface. Thetemperature of the water at the surface continues to fall to 0 0 C.

6. Finally, the water at the surface is converted into ice, but the water below

the layer of ice is at 40

C.7. Ice is a bad conductor of heat. Hence, the layer of the ice at the surfacedoes not allow transfer of heat from the water to the atmosphere.

8. As the water below the layer of ice remains at 4 0 C, fish and other aquaticanimals and plants can survive in it.

Q 3 . Answer the following questions:-

1. What is Anomalous behavior of water? (OR)Describe its role in the survival of the aquatic plants and animals in

cold countries.Ans.1. Generally, liquids expands on heating and contract on cooling. Water,

however shows an exceptional behaviors below 4 0C.2. If water at room temperature is cooled continuously, it goes on contracting

till its temperature falls to 4 0C.3. But as its temperature falls below 4 0C, it starts expanding instead of

contracting.4. Similarly, if water is heated form 0 0 C to 4 0C, it contracts instead of

expanding.5. This exceptional behaviors of water is known as the anomalous behaviors

of water.6. In cold countries, during winter, the temperature of the atmosphere falls

well below 0 0 C.7. As the temperature decreases, the water at the surfaces of lakes and

ponds starts contracting.8. Hence, its density increases and it sinks to the bottom. This process

continues till the temperature of all the water in the lake falls to 4 0 C.


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HEAT9. As the water at the surface cools further, its temperature falls below 4 0 C, it

starts expanding instead of contracting.10. Therefore, its density decreases and it remains at the surface. The

temperature of the water at the surface continues to fall to 00

C.11. Finally, the water at the surface is converted into ice, but the water belowthe layer of ice is at 4 0 C.

12. Ice is a bad conductor of heat. Hence, the layer of the ice at the surfacedoes not allow transfer of heat from the water to the atmosphere.

13. As the water below the layer of ice remains at 4 0 C, fish and other aquaticanimals and plants can survive in it.

2. Write the unit of heat in M.K.S and C.G.S systemAns. Unit of heat in

M.K.S. system is Kilocalorie.

C.G.S system is Calorie.3. Explain the formation of dew and fog.Ans. During the day time the quantity of water vapour in air is not sufficient tosaturate the air. During the cold night temperature may fall to dew point. At thistemperature air becomes saturated with water vapour.As the temperature falls below the dew point, water vapour in air condenses onthe surface of cold bodies and dew is formed. Sometimes condensation of water vapour occurs on the fine dust particles present in the atmosphere and this givesrise to the formation of fog or moist.

4. Explain Hopes apparatus with the help of neat and labeled diagram.


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HEAT

7. Give two examples of the anomalous behaviour of water withexplanation. (or)

State two effects of anomalous behaviour of water observed innature.Ans.1. Some times water enters into crevices of the rocks. When the temperature of the atmosphere falls below 4 0C, water expands. As there is no room for expansion, it exerts a tremendous pressure on the rocks, which breaks up intosmall pieces.

2. In cold countries, in winter, when the water of lakes freezes, the ice formedfloats on the surface of water. Hence, the aquatic animals and plants in the water

below the layer of ice are protected from being frozen to death.


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MODERN PHYSICS3. State the nature of particle, particle and Y radiation.Ans.1. An particle is the nucleus of helium.

2. A particle is an electron.3. Y radiation consists of electromagnetic waves of very short wavelength of the order of 10 -10 m.

4. State the laws of radioactive transformation.Ans. Laws of radioactive transformation are:1. When an atom of radioactive element emits an Particle, its mass numberdecreases by 4 and atomic number decreases by 2.2. When an atom of radioactive element emits a Particle, its mass number remains the same but atomic number increases by 1.3. When an atom of a radioactive element emits Y radiation, its mass number

and atomic number remain unchanged.

5. State the four properties of Particles. Ans.1. An Particle is a positively charged particle.2. It is the nucleus of helium.3. Particle have velocities ranging from 1/10 th to 1/100 th of the velocity of light.4. Their ionizing power is very high.5. Their penetrating power is small.6. They can only pass through very thin sheets of paper.7. They effect photographic plates.8. They produce fluorescence in florescent substance like zinc sulphide.

6. State the four properties of particles.Ans.1. An particle is a negatively charged particle.2. A particle is an electron.3. particles have very high velocities.4. Some particles have velocity equal to 99% of velocity of light.5. Their ionizing power is small compared to that of particles.6. Their penetrating power is greater that that of particles,7. particles can pass through thin sheets of metals.8. They effect photographic plates.9. They produce fluorescence in fluorescent substance lime zinc sulphide.


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MODERN PHYSICS7. State the four properties of Y radiations.Ans.1. Y Radiations are electromagnetic waves of very short wavelength of the

order of 10-10

m.2. Being electromagnetic waves, their velocity is the same as the velocity of light.3. Their ionizing power is very small compared to the other two particles.4. Their penetrating power is very high compared to the other two particles.5. They affect photographic plates.6. They produce fluorescence in fluorescent substance like zinc sulphide.

8. State the four properties of cathode rays.Ans.1. Cathode rays are emitted in a direction normal to the surface of the cathodeand this direction is independent of the position of the anode.

2. They travel in a straight line.3. They exert mechanical force on an object in their path.4. They are deflected by a magnetic field.5. They produce fluorescence in many substance like zinc sulphide.6. When an obstacle stops them, X rays are produced.9. State the four properties of X raysAns.1. X rays are electromagnetic waves of very short wavelength of the order 10 -6m.2. They posses all properties of visible light such as rectilinear propagation,reflection, refraction etc.

3. Being electromagnetic waves they travel in air or vacuum with the speed of light.4. They are not deflected by electric or magnetic field.5. They posses very high energy. Hence, they can penetrate through densematerial such as iron, lead etc.

10. State the uses of cathode rays.Ans. Uses of cathode rays are1. Cathode rays are used to produce X rays.2. Cathode rays produce fluorescence in fluorescent substances.3. Cathode rays are used in the picture tube of T.V. receiver.


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MODERN PHYSICS11. State the uses of X raysAns. Uses of X rays are _ 1. To detect fracture of bones.

2. To detect the presence of foreign materials in a human body.3. To detect diseases of lungs, kidneys etc.4. To cure skin diseases and malignant tumor hidden deep within the body.5. To distinguish real diamonds from artificial ones.6. To detect explosives and drugs hidden in bags or packages.7. To study the structure of crystals.

12. Describe in brief the experiment to show that cathode rays are emittedin a direction normal to the surface of the cathode and this direction isindependent of the position of the anode.

Ans. In a discharge tube, even if the anode is fitted on one side, the fluorescentspot is observed in front of the cathode as shown in the figure. This shows thatcathode rays are emitted in a direction normal to the position of the anode.

13. Describe in brief the experiment to show that cathode rays travel in astraight line.Ans. If an object is placed in front of the cathode in a discharge tube, a sharpshadow of the object if formed in the fluorescent region of the tube as shown infigure. This shows that cathode rays travel in a straight line.


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MODERN PHYSICS14. Describe in brief the experiment to show that cathode rays exertmechanical force on an object in their path.Ans. A paddle wheel free to roll on horizontal rails is kept inside the discharge

tube in such a way that the cathode rays are incident only on the upper part of the wheel. When tube is operated by switching on the D.C. supply, the cathoderays fall on the wheel and hence, the wheel rolls away from the cathode. Thisshows that cathode rays exert mechanical force on an object in their path.

15. Describe in brief the experiment to show that cathode rays are deflectedin an electric field.Ans. A uniform electric field is produced in the region between the plated P 1 andP 2. When the cathode rays pass through the electric field, they are deflected

towards the positive plate indicating that the cathode particles are negativelycharged as shown in the figure.


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MODERN PHYSICS16. Describe in brief the experiment to show that cathode rays are effectedin a magnetic field.Ans. The experimental arrangement used to study the effect of a magnetic field

on cathode rays. A strong horse shoe magnet is used to produce a magnetic fieldat right angles to the plane of the paper and directed inward. When the cathoderays pass through the magnetic field, they are deflected downward. Hence, thefluorescent sport is displaced downward. The direction of the deflections showsthat the cathode particles are negatively charged.

Q3. Give scientific reasons.1. X rays are used for detection of fracture of bones.

Ans. X rays can pass through skin and flesh, but they cannot pass throughbones. Hence, X rays photographs are used for detection of fracture of bones.

2. While using X rays for curing skin diseases or other diseases, longexposure to the X- rays should be avoided.Ans.1. X rays kill living cells.2. They kill healthy tissues in the part exposed to X rays. Hence, while using X

rays for curing skin diseases or other diseases, long exposure to X raysshould be avoided.

3. X rays are invisible.Ans.1. X rays are electromagnetic waves having very short wavelengths of theorder 10 -6 meters.2. The only difference between X rays and visible light is that X rays haveshort wavelengths. Therefore X rays are invisible.


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MODERN PHYSICS4. X rays are used to detect smuggling of gold and silver.Ans.1. X rays cannot penetrate through gold and silver.

2. X rays photograph reveals the presence of hidden metal in bags andpackages of the passengers. Hence, X- rays are used to detect smuggling of gold and silver.

Q4. Distinguish between-1. particles and Cathode rays. Particles Cathode rays1. These are electrons emitted by aradioactive atom.2. When a tungsten plate stops Particles we do not get X rays.

3. When Particles emitted, theatomic number of the atomincreases by one unit.

1. These are also electrons that come fromcathode of an evacuated cathode ray tube.2. When a tungsten plate suddenly stopscathode rays, we get X rays.

3. Cathode rays are free electrons emittedfrom the cathode. Hence, there is nochange in atomic number.

2. Particles and particles Particles Particles1. The Particles consists of twoprotons and two neutrons. Hence, we say it the nucleus of Helium atom.2. Particles have velocity rangingfrom 1/10 th to 1/100 th of that of light.3. particles have very low penetrating

power.4. Particles are deflected towardsnegative plate.5. When a particles are emitted theatomic number decreases by two andatomic mass number decreases by four.

1. Particles are electrons.2. Particles have very highvelocity up to 99% of the velocity of light.3. Particles can penetrate 100times more than particles.

4. Particles are deflected towardsanode plate.5. When Particles are emittedatomic number increases by oneunit; mass number does not change.

3. X Rays and Y Rays.X rays Y - rays1. These are electromagnetic rays of very short wave length produced whenthe path of cathode rays are

obstructed.2. When x rays fall on a metal plate,the place emits electrons.3. X rays have the velocity of light.4. X rays have the properties of lightrays; they can penetrate throughmuscles, tissues but not throughbones.

1. These are also electromagnetic raysof very short wave length but emitted byan atom the nucleus of an radioactive

atom.2. Y rays do not knock out electronsfrom metal plate.3 . Y rays also has the velocity of light.4. Y rays do not have all the propertiesof light but they can penetrate evenbones.


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DIETARY DEFICIENCY DISEASES Q. 1 Define

1. Under nutrition: - Intake of insufficient food is called under nutrition. Under nutrition is very common among the poorer sections of the society. Under

nourished people are prone to diseases like rickets, anemia, cold, coughand fever.2. Over nutrition: - Intake of excessive food is called over nutrition. Over

nutrition is seen among the richer section of the society. Over nourishedpeople become obese and overweight. They become prone to diseases likediabetes, arthritis, hyper tension and other cardio vascular diseases.

3. Malnutrition: - Malnutrition means disordered nutrition which is due to lackof sufficient food or excessive intake of food.

4. Night blindness: - Night blindness is a deficiency disease of the eyecaused due to the deficiency of vitamin A in diet.

5. Beriberi: - Beriberi is a deficiency disease caused due to the deficiency of

Vitamin B 1 .6. Rickets: Rickets is a disease caused by the deficiency of calcium,phosphorus and vitamin D.

7. Marasmus: - Marasmus is a disease caused by the deficiency of energy,proteins and other nutrients.

8. Pellagra: - Pellagra is a disease caused by the deficiency of Vitamin B 3(niacin)

9. Scurvy: - Scurvy is a disease caused due to deficiency of Vitamin C(Ascorbic acid). It is very common in infants.

10. Anemia: - Anemia is a disease caused by the deficiency of iron.11. Kwashiorkor: Kwashiorkor is a disease caused by the deficiency of

protein. It occurs when babies are taken away from protein rich breast milkto other foods, which are not rich in proteins and energy.

Q 2 .Give reasons

1. Malnutrition is hazardous.Ans. malnutrition is hazardous because.1. It effects the physical and physiological well being of an individual.2. The physical, mental and social performance of a malnourished individual

becomes abnormal.3. Malnourished children become prone to diseases like marasmus, rickets andanemia.


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DIETARY DEFICIENCY DISEASES

2. In India, there are high incidence of nutritional deficiency diseasesamong the poorer section of the society.

Ans.1. In India among the poorer sections of the society even the intake of basiccalorie requirement is not fulfilled.

2. Proteins, vitamins and minerals are not consumed at desired levels. Therefore,there is high incidence of nutritional deficiency diseases among the poorer section of the society.

3. Babies should not be weaned from breast milk to other diets deficient inproteins and energy.

Ans.1. Breast milk contains carbohydrates, proteins and fats, which can be easily

digested and absorbed.2. If proteins are not provided in sufficient quantities, the baby may suffer fromprotein energy malnutrition leading to Kwashiorker and marasmus. Therefore,babied should not be weaned from breast milk to other diets deficient in proteinand energy.

4. Rickets is common among those children who are deprived of sunlight.Ans.1. Rickets is caused by the deficiency of vitamin D.

2. Vitamin D is synthesized by the body, if the skin is exposed to morning sun.Therefore, rickets is common among those children who are deprived of sunlight.

5. Goitre is more prevalent among the people who reside in mountainousregions.Ans.1. In mountainous regions iodine content of the soil and water is low.2. This leads to deficiency of iodine, which causes goitre. Therefore, goitre ismore prevalent among the people who reside in mountainous regions.

6. Pellagra occurs in people living on a maize diet.Ans.1. Pellagra is due to the deficiency of vitamin B 3 (niacin)2. Maize does not contain niacin. Hence, pellagra occurs in people living on amaize diet.


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7. Beriberi is observed mainly amongst people who eat polished rice.Ans.

1. Beriberi is caused due to the absence of Vitamin B 1 . (Thiamine)2. Polished rice lacks B 1 . (Thiamine). So Beriberi is observed mainly amongstpeople who eat polished rice.

8. Scurvy is observed among the people whose diet is deficient in freshfruits.Ans.1. Scurvy is due to gross deficiency of vitamin C.2. Fruits contain vitamin C. Therefore, scurvy is observed among the peoplewhose diet is deficient in fresh fruits.

Q 3 .Answer the following questions.1. Mention the hazards of Malnutrition (TB) OR

What are the general effects of physical and physiological well being of aunder nourished and over nourished person.

Ans.Undernourished person:

1. Weight and height is below the standard value.2. Physical, mental and social performance is below normal.3. The under nourished person is susceptible to infection due to low

resistance of the body.

4. The under nourished person becomes prone to diseases likerickets, anemia infectious diseases like cold, sough, fever etc.Over nourished person:

1. An over nourished person becomes over weight and obese.2. The over nourished person becomes prone to diseases like diabetes,

arthritis, cardio vascular disorder etc.

2. What is night blindness? What are its symptoms?

Ans. Night blindness is a deficiency disease of the eye caused due to thedeficiency of

vitamin A in diet.Symptoms of night blindness:

1. Unable to see in dim light particularly after exposure to bright light.2. Xeroderma (dry and scaly skin)


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3. What is beriberi? What are its symptoms?Ans. Beriberi is a deficiency disease caused due to the deficiency of vitamin B 1 .

Symptoms of beriberi_ 1. Loss of apatite.2. Muscle weakness3. degeneration of nerve tissues4. Some times odema is observed5. Mental alertness decreases6. Memory may become faulty.7. Concentration becomes poor.8. Person becomes unstable emotionally.

4. What is rickets? What are its symptoms?

Ans.1. Rickets:- Rickets is a deficiency disease caused by the deficiency of calcium,phosphorus and vitamin D.2. Symptoms of rickets:- 1. Faulty mineralization of bones and teeth. 2. Skeletalmalformation resulting into twisted bones. 3. Late eruption of teeth.

5. What is scurvy? State its symptoms.Ans.1. Scurvy :- Scurvy is a deficiency disease caused due to the deficiency of vitamin C (Ascorbic acid ) in diet.2. Symptoms of scurvy :- 1. Swelling and bleeding of gums. 2. Reduction in

resistance of the body to infections. 3. Poor healing of wounds. 4. Subcutaneoushaemorrhage. 5. Irritability.

6. What is pellagra? Give the important symptoms of pellagra.Ans.1. Pellagra:- Pellagra is the deficiency disease caused by the deficiency of vitamin B 3 (Niacin) in the diet.2. Symptoms of pellagra:- 1. Rough, scaly and ulcerated skin. 2. Darkening of complexion due to hyper pigmentation. 3. Soreness of mouth. 4. Diarrhoea andfatigue. 5. Listlessness and depression. 6. Headache and backache.

7. What is marasmus? What are its symptoms?Ans.Marasmus:-1. Marasmus is a malnutrition disease characterised by the stuntedgrowth of a child.2. Marasmus occurs due to the deficiency of proteins, carbohydrates and fats inthe diet of infants.


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Symptoms of marasmus are:1. The child is reduced to skin and bones owing to wasting of muscles.

2. The skin becomes shrunken.3. Eyes become large in size.4. The ribs of marasmic child look very prominent.5. Dehydration occurs in the body due to watery Diarrhoea and vomiting.

8. Give the important symptoms of anaemia. (or) What is anaemia? How isit caused? (or) What is the causes of anaemia? What are its symptoms?(or) State the disease caused due to the deficiency of iron. Give its twosymptoms?Ans.Anaemia:- Anaemia is a deficiency disease caused by the deficiency of iron in

the diet. In anaemia, the haemoglobin content of the blood goes down.Symptoms of anaemia:-1. Pale appearance of the skin, fingernails and mucous membrane.2. Frequent headache.3. Breathlessness and palpitation.4. Constant feeling of tiredness and giddiness.5. Insomnia.

9. What is Kwashiorker? What are its symptoms?Ans. Kwashiorker is a disease caused by the deficiency of protein. It occurs

when babies are taken away from protein rich breast milk to other foods, whichare not rich in proteins and energy.Symptoms of Kwashiorker:-

1. The child becomes listless and miserable.2. Child becomes apathetic with no interest in his surroundings.3. Cheerless with no apetite.4. Weight and height is below normal.5. Oedema occurs due to loss of nitrogen, which leads to full round face

called moon face.6. Circumference of upper arm is reduced due to muscle wasting.7. Abdomen swells and liver enlarges causing potbelly.8. There is discoloration, redness, sparseness and easy pluckability of

hair.9. Skin cracks and becomes scaly, inflamed and reddish.


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15. Baskar has brittle and weak bones. State the disease he is sufferingfrom. Name the deficient vitamin. Suggest measures on it.

Ans.1. Baskar is suffering from rickets, which is due to the deficiency of vitamin D.2. Baskar should expose his body to morning sun. Besides he should take egg,fish liver oils and butter in his daily food.

16. The following report is observed in the school health inspection. Namethe diseases.a. Vasu cannot see in dim light.b. Bleeding gums of pritesh. (March 2001)Ans. a. Night blindnessb. Scurvy

17. Which deficiency in food is responsible for the following diseases.

Ans.Marasmus -------- Protein, energy and other nutrients.Pellagra -------- Niacin (B 3)Anaemia -------- IronRickets -------- Calcium, phosphorus and vitamin DNight Blindness -------- Vitamin A

Q4. Distinguish between.1. Kwashiorker and Marasmus

Kwashiorker Marasmus1. It is a disease of children caused bythe deficiency of protein in the diet.2. In this, there is Oedema on the bodyof the child.3. The circumference of the upper armof the child is reduced due to musclewasting.

4. The skin of the child cracks andbecomes scaly.5. The face looks like a moon.

1. It is a disease of children caused bythe deficiency of proteins, energy andother nutrients in the diet.2. There is no oedema on the body of the child.3. The child is reduced to mere skinand bone due to muscle wasting.

4. The skin becomes shrunken.5. The face looks like an old personface.


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DISEASES DUE TO OVERINTAKE OF

SOME NUTRIENTSQ1. Give scientific reasons:-

1. Excessive intake of water soluble vitamins has no ill effects on thebody. (or) Water soluble vitamins cannot be stored in the body.Ans.1.These vitamins dissolve in water.2. They are easily excreted out of the body along with urine. Hence, excessiveintake of water soluble vitamins has no ill effects on the body.

2. Excessive intake of fluorine should be avoided.Ans.1. The over consumption of fluorine begins to discolour the teeth enamel.

2. It also leads to abnormal calcification of bones, known as Bone FluorosisHence, excessive intake of fluorine should be avoided.

3. Excessive intake of high calorie diet should be avoided.Ans.1 The over consumption of high calorie diet leads to overweight and obesity.2. Such people may suffer from hypertension, liver disorders, renal disorders andheart disorders. Hence, intake of high calorie diet should be avoided.

4. Excessive intake of synthetic vitamin A in children results in maycomplications.

Ans.1. It causes hyper vitaminosis of vitamin A.2. It is a fat soluble vitamin and therefore remains in the body and is notexcreted out.3. It results in itching of skin, painful swelling of legs and hands and enlargementof spleen.

5. Excessive intake of saturated fats in our diet should be avoided.Ans.1. Fats give energy two times more than the amount of energy given bycarbohydrates.2. Some fat get deposited on the inner walls of the arteries causingarteriosclerosis and obesity.3. It also leads to cardio vascular diseases and other complication likehypertension, diabetes, etc.Hence, excessive intake of saturated fats in our diet should be avoided.


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SOME NUTRIENTSQ2. Answer the following.

1. How high blood pressure is caused and how is it prevented?Ans.1. High blood pressure is caused due to the excess of fats.2. It can be controlled by prevention of obesity.3. One should take required amount of saturated fats to control obesity.4. Intake of salts should be restricted after the age of 35 years.

2. What is diabetes? How is it caused? How is it prevented?Ans.1. Diabetes is the disease in which the level of glucose in blood increase beyond

normal level and glucose is excreted through urine.2. A hormone insulin controls blood glucose level.3. Obesity interferes the action of insulin and is one of the causes of diabetes.Which is caused in adults.4. If obesity is reduced and controlled, diabetes will be automatically controlled.

3. Write the dietary caused through the following disorders:-

1. High blood pressure.2 Inadequate blood supply.3. Pitted teeth.

4. Dryness and itching skin.5. Facial paralysis.

Ans.1. Dietary causes of high blood pressure.

a. Excessive intake of saturated fats.b. Intake of salts in excess.

2. Dietary causes of inadequate blood supply.a. Excessive intake of fats.

3. Dietary causes of pitted teeth.a. Excessive intake of fluorine.

4. Dietary causes of dryness and itching skina. Excessive intake of vitamin A.

5. Dietary causes of facial paralysis.a. Excessive intake of vitamin D.


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SOME NUTRIENTS

4. State the necessary precautions to avoid the following disorders.1. Arteriosclerosis.2. To control diabetes.3. Obesity.

Ans.1. Arteriosclerosis:- Arteriosclerosis can be avoided by restricting he consumptionof fat and fat rich nutrients.2. To control diabetes:- It can be controlled by controlling the obesity and bycontrolling the diet.3. Obesity:- It can be avoided by restricting he quantity of fats and carbohydrates

in the diet.5. What are the possible disorder due to the consumption of following.1. High calorie diet.2. Saturated fat.3. Fluorine.4. Vitamin A in children s diet5. Vitamin C

Ans.1. High calorie diet: The over consumption of high calorie diet leads to

overweight and obesity. Such people may suffer from hypertension, liver disorders, renal disorders and heart disorders.2. Saturated fat: The over consumption of saturated fat leads to blood pressureand arteriosclerosis, leading to heart disease, paralysis and gangrene.3. Fluorine:- The over consumption of fluorine begins to discolour the teethenamel. It also leads to abnormal calcification of bones, known as BoneFluorosis4. Vitamin A in childrens diet:- The over consumption of vitamin A in childrensdiet results in dry itchy akin, painful swelling of legs and hands thickening of longbones and hyper irritability.5. Vitamin C:- The over consumption of vitamin C has no ill effects on the bodyas they are easily extracted through urine.

6. Give the disadvantages of excessive intake of nutrients.Ans. The disadvantages of excessive intake of nutrients are:1. Excessive intake of nutrients is wastage of nutrients.2. Excessive intake of nutrients results in various disorders of the body leading todisability and pre matured death.3. Excessive intake of nutrients leads to overweight and obesity.


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SOME NUTRIENTS

7. Explain hypervitaminosis.Ans. Disorders or diseases resulting from the over intake of vitamins is calledhypervitaminosis. Hypervitaminosis is caused mainly due to excess consumptionof fat soluble vitamins like vitamin A, Vitamin D, etc.1. Hypervitaminosis of vitamin A occurs when concentrated from of syntheticvitamin A is administered for a larger period. Following symptoms are commonlyobserved in the children. Dry itchy skin, painful swelling of legs and handsthickening of long bones, occasional enlargement of spleen, hyper irritability. Inadults, complaints such as fatigue, general weakness, insomnia, constipation,nail changes, bone and joint pains etc. are observed.2. Hypervitaminosis of vitamin D causes nausea, fatigue, vomiting, drowsiness,

hypertension, renal damage, calcium deposition in large blood vessels and in softtissues, facial paralysis and anaemia etc.

8. What happens when an adult takes vitamin A in excess?Ans. Excessive intake of vitamin A causes following disorders in adults.1. Fatigue2. General weakness3. Insomnia4. Constipation5. Nail changes6. Bone and joint pains.


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FOOD WASTAGEQ1. Give scientific reasons:

1. Immature grains should not be harvested.

Ans. Immature grains should not be harvested because1. They deteriorate quickly as enzymes are still active in them.2. The grains also have high proportion of moisture in them which is favourablecondition for enzyme reaction.

2. Wet grains should not be dried in the hot sun.Ans.1. Drying of wet grains in the sun results in their cracking leading to increasedinfestation by insects.2. Hence, wet grains should not be dried in the hot sun.

3. Grapes should not be handled by untrained labourers.Ans.1. Untrained labourers handle grapes roughly during harvesting and packing.2. Owing to this grapes get spoilt completely.3. Hence, grapes should not be handled by untrained labourers.

4. Jaggery should not be packed in gunny bags during rainy season.Ans.1. Jaggery should not be packed in gunny bags during rainy season, because itresults in both qualitative and quantitative loss of the commodity.2. Moreover, the commodity becomes unacceptable in the market because of its

contamination by both live and dead insects and their excreta.5. Potatoes should not be stored for a long time.Ans. Potatoes should not be stored for along time, because1. Potatoes sprout during storage.2. Sprouting leads to qualitative and quantitative losses of their nutritive values.

6. Losses of perishable foodstuffs are higher than nonperishablefoodstuffs.Ans.1. Perishable foodstuffs have a short shelf life as compared to non perishablefood stuffs.2. Therefore, losses of perishable foodstuffs are higher than non perishablefoodstuffs.

7. Grapes get spoiled during packing.Ans.1. Grapes get spoilt if packed in rigid wooden boxes.2. Therefore, grapes get spoiled during packing.


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FOOD WASTAGE8. Due to defective mode of distribution more wastage of food takes place.Ans.1. Improper packaging, marketing and transport arrangements for distribution of

food are responsible for wastage of food.2. Therefore, due to defective mode of distribution more wastage of food takesplace.

9. Over ripening of fruits should be avoided.Ans.1. Over ripening of fruits get spoiled due to enzymatic action.2. Therefore, over ripening of fruits should be avoided.

10. Buffet system of food serving should be followed at public places.Ans.

1. Buffet system of food serving is useful in minimizing the wastage of food.2. Therefore, buffet system of food serving should be followed at public places.

11. Overcooking of food should be avoided.Ans. Overcooking of food should be avoided, because:1. Overcooking disintegrates the food.2. Owing to this, the colour and flavour of food is lost.3. Therefore, overcooking of food should be avoided.

12. Cooking of food in an open pan should be avoided.Ans.

1. Cooking of food in an open pan results in losses of vitamins.2. Therefore, cooking of food in an open pan should be avoided.

13. Chopped vegetables should not be washed.Ans.1. Washing of chopped vegetables results in loss of nutritive quality.2. Therefore, chopped vegetables should not be washed.

14. Bananas should not be kept in a refrigerator.Ans. Bananas turn black if they are stored at low temperature. Hence, bananasshould not be kept in a refrigerator.


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FOOD WASTAGEScientific methods of post harvesting practices and storage.1. After harvesting, transportation and storage facilities must be adequate and

proper safe storage go-downs should be built according to the nature of foodstuffs.2. There must be proper arrangements of temperature and moisture control.3. Godowns must be well ventilated and protected from pests.4. Before storage, grains should be properly dried and cleared off from infectedand spoiled materials and other impurities.5. Periodical checking and pest control treatments are necessary to increase theself life of foods.6. Adaptation of new technologies for harvesting and storage, training for proper handling to the food handlers are some of the solution to minimize the losses of food stuffs.

5. List the causes of food wastageAns. Causes of food wastage are1. Defective post harvest practices.2. Improper handling of foodstuffs.3. Losses during transport and milling of foodstuffs.4. Defective modes of storage and distribution of food.5. Losses due to traditional custom.

6. What will happen if the food is not handled properly?Ans. Effects of improper handling of food are as follows.1. Rough handling by untrained labours is a major cause of food wastage.

2. Losses are more in perishable foodstuffs, particularly during harvesting,packing, transporting, etc.3. Delicate grapes if roughly harvested and packed in rigid wooden boxes, willget spoil completely.4. Careless digging of sweet potatoes, causes injury to them.

7. Explain how qualitative loss of nutritive nature of food takes place due tofaulty pre marketing process.Ans. The following faulty pre marketing processes can lead to qualitative lossof food:1. Improper time of harvesting crop.2. Wrong judgment of time required for foodstuffs to reach the market.3. Damage to perishable goods during harvesting.4. Wrong judgment of the likely time gap between production and marketing.5. Lack of knowledge of available modes of packaging, storage, transport,distribution etc.


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FOOD WASTAGE8. Enlist the faulty cooking methods.Ans. Faulty cooking results in the loss of certain nutrients.1. Over cooking may disintegrate food or may lose its colour, flavour etc.

2. Cooking with water in open pan results in greater losses of vitamins.3. The water from cooked food if thrown away, protein, minerals and vitamins getlost.4. Washing fruits or vegetables after cutting affects the nutritive quality of thefood besides its acceptability.

9. Explain why harvesting of crops must be done at proper time?Ans.1. If immature crops are harvested they will deteriorate more quickly than maturegrains, as the enzymes are still active.2. If the grain remains in the field after maturity, occasionally it becomes wet due

to rain and drying of such grains in the hot sun may cause grains to crack, thusincreasing the likelihood of infestation by insects.

10. Write a note on white revolution.Ans.1. Increase in production of milk by high yielding varieties of animals is calledwhite revolution.2. In 1970 Government of India, in collaboration with Denmark, New Zealand andother countries started improving Indian breeds of cows and buffaloes.3. As a result high yielding varieties of cows and buffaloes were developedleading to white revolution.

4. Aarey dairy at Mumbai, Amul dairy at Anand in Gujarat and Warna dairy atKolhapur have contributed to white revolution.

11. Write a note on green revolution.Ans.1. Increase in the production of food grains by developing high yielding varietiesof crop plants with the help of new scientific methods and technologies is calledgreen revolution.2. The population explosion in India, after independence created increasing

demands for food supply.3. To meet the ever increasing demands for food, efforts were made to increasethe production of food grains.4. In 1960s scientists realized the importance of high yielding varieties of cropplants for increasing the production of food grains.5. Many hybrid varieties of crop seeds were used which led to tremendousincrease in food production.


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FOOD WASTAGEQ3. Write short notes on1. Losses of food during farm level operation:1. It includes various process such as threshing and drying grains, bagging or

placing threshed grain in other containers, grading or sorting of fruits, bundling of leafy vegetables, transport from field to storage, mill or market etc.2. Losses of non perishable foodstuffs occur due to their post harvest qualityand threshing and shelling by using hand brake method or by use of animals.3. Losses of perishable foodstuffs due to their short self life.

2. Losses of food during transport.1. It is due to transport from field to storage place or to processing place.2. During this transits, loss may occur due to continued deterioration of perishable food or spoilage of bagged grains exposed to rain, or spoilage due todefective or damaged containers etc.

3. The use of hooks to handle sacks of grains in port is also one of the examplesof poor handling, causing loss.

3. Loss of food due to the defective modes of storage:-1. Food losses during storage are quite high.2. Variation in temperature, humidity and moisture are responsible for damageduring storage.3. In hot damp conditions, the deterioration of food takes place due to the rapidgrowth of micro organism and insect population.4. Unsuitable container used for the storage of food materials also plays sub rolein loss of food.

4. Loss of food due to defective modes of distribution:-1. Improper packaging, marketing and transport arrangements for distribution areresponsible for food wastage.2. The percentage of wastage is more among perishable foods, especially duringsummer or rainy seasons.3. Rough handling or vibration in overloaded trucks on poor roads causes physicaldamage to the delicate perishable foodstuffs like vegetables, fruits, fish etc.

5. Loss of food due to traditional customs:-1. A considerable amount of food materials are lost in many houses due towasteful and inefficient management.2. Many a times more than required quantity of food is purchased, especially byprivileged section of the society.3. Some amount of food is also wasted due to may customs and practices.4. For example, a considerable amount of food prepared for feast during socialand religious functions is wasted due to improper management.5. The wastage of good also occurs due to faulty serving methods.6. Even in hotels, boarding, hostels, etc a large amount of food is wasted.


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FACTORS CAUSING FOODSPOILAGE

Q1. Define

1. Natural preservatives: - The naturally occurring food stuffs such as sugar, oiland apices which are used for preserving food are called natural preservatives.

2. Asepsis:- Keeping out microorganisms from food is called asepsis.

3. Food spoilage:- The undesirable change in food which makes it unfit for human consumption is called food spoilage.

4. Developed preservatives:- During certain processes, some products can bedeveloped having a preservative effect. Such products are called developed

preservatives.5. Artificial preservatives:- The synthetic chemicals that are used for thepreservation of food are called artificial preservatives.

6. Food poisoning:- An acute illness resulting from the ingestion of foodcontaining poisonous substances are called food poisoning.


1. Packaging material for food should be selected properly.

Ans. Packaging material for food should be selected properly because1. The material should be non reactive, non toxic and non corrosive so as toavoid spoilage of food.2. To maintain the quality of food, it depends upon the packaging material usedfor its packing.

2. Potable water must be used for foodstuffs.Ans. Potable water must be used for food stuffs because1. Potable water is free from micro organisms.2. It does not contaminate the food.

3. Potatoes are irradiated before storing.Ans. Potatoes are irradiated before storing because1. Potatoes sprout during storage.2. To avoid the potatoes from sprouting they are irradiated with gamma rays.


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4. A high standard of cleanliness must be maintained at food processing

plants. (or)Food handlers should be hygienically clean.Ans. A high standard of cleanliness must be maintained at food processing plantsbecause1. Most of the diseases and contamination of food is brought due to unhygienicconditions of the food handlers.2. Pathogens can be transmitted to other via the agency of food handlers.3. Many communicable and contagious diseases are spread if food handlers donot maintain health and hygiene.

5. Fruits and vegetables should not get bruised.

Ans. Fruits and vegetable should not get bruised because1. Bruising facilitates the entry of micro organisms.2. They use the nutrients of food for their growth and activities there by decreasethe nutritive value.3. They also release toxins, which contaminates the fruits and vegetables.

6. Milk should be preserved at low temperature.Ans. Milk should be preserved at low temperature because1. Low temperature treatment retards the chemical and enzymatic reactions.2. It also slows down or stops the growth of micro organisms.3. Milk can remain fresh without contamination for a longer period if stored at low

temperature.7. Combinations of different preservative methods are used for preserving

jams.Ans. Combinations of different preservative methods are used for preserving

jams because.1. Single method of preserving is not effective.2. For preparing jam three methods are involved such as asepsis, use of hightemperature and use of preservative i.e. sugar.

8. Use of high temperature is essential for food preservation.Ans. Use of high temperature is essential for food preservation because1. The micro organisms can be killed by using high temperature.2. The enzymes present in food can also be inactivated by heating, boiling etc.


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9. Use of low temperature is a method of food preservation.

Ans. Use of low temperature is a method of food preservation because.1. Low temperature treatments are useful to retard chemical and enzymaticreactions.2. They are also useful to slow down or stop growth and activity of micro organisms.

10. Butter milk should not be kept in a brass vessel.Ans. Butter milk should not be kept in brass vessel because,1. Butter milk contains an organic acid called as lactic acid.2. The lactic acid present in the buttermilk reacts with the brass vessel.3. The chemical reaction brings about spoilage of butter milk, which is unfit for

consumption.11. Cut meat should not be kept for long time.Ans.1. After slaughtering killing animals certain chemical changes takes place.2. Degradation of glycogen continues to form intermediate product specially lacticacid.3. Lactic acid increases acidity of meat, which affects the nutritive value of thefoodstuffs. Hence, cut meat should not kept for longer time.

12. Groundnuts are stored for a longer period.

Ans.1. They turn rancid and develop an undurable flavour in it.2. This is due to chemical reaction in it. Hence, groundnuts are stored for alonger period.


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5. Use of Low temperature:- Low temperature is useful to retard chemical and

enzymatic reactions. They are also useful to slow down or stop growth andactivity of micro organisms. E.g. use of refrigerator or cold storage for milk,fruits, vegetables, meat etc.6. Drying:- Preservation of food by sun drying has been practiced for centuries.It can also be done by using mechanical drier.7. Use of chemical additives:- Some food stuffs are preserved by making use of certain natural chemicals such as sugar, salt, oil spices and synthetic chemicalssuch as sodium benzoate, citric acid, etc. During certain process some productscan be developed which act as preservatives. E.g. Acid during fermentation.8. Irradiation:- Radiations of various frequencies are used to preserve food stuffs,for example. To avoid sprouting of stored potatoes they are irradiated with

gamma rays.

Q3. Explain different ways of maintaining aseptic conditions of foodpreservation.Ans. The different ways of maintaining aseptic conditions of food preservationare:1. Maintenance of clean environment:- A high standard of cleanliness should bemaintained in the premises where food is harvested, stored, processed etc.2. Cleanliness of food:- Foodstuffs may contain micro organisms. Therefore,they should be cleaned properly with clean water to minimize their contamination.

3. Cleanliness of food handlers:- A person who handles the food must maintain ahigh standard of cleanliness. He should have the basic knowledge of theprinciple of sanitation and hygiene.4. Packaging material:- Packaging material for food should be non reactive,non corrosive and non toxic,, so that the food quality is maintained.5. Cleanliness of equipments and utensils:- Equipments used in handling foodlike choppers, knives, tongs, etc. Should be washed with hot water or sterilized.6. Use of potable water:- Impure water may be a major cause of a source of contamination, as it carries micro organisms. Therefore clean water should beused.7. Safe disposal of leftover food and food waste:- Left over food should becovered and stored in a cool dry place, preferably in a refrigerator. Food wastelike peels, seeds, bones etc. should be disposed off in garbage cans with lids.The disposal of waste should be done with proper care.


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4. What are preservatives? Describe its types?

Ans. Preservatives are chemical substances or food additives, which are addedto foodstuffs to increase their shelf life. Preservative play an important role infood preservation inhabit the spoilage of food.Preservatives are classified into the following groups.1. Natural preservative:- The naturally occurring foodstuffs such as sugar, salt, oiland spices which are used for preserving food are called natural preservatives.For example, sugar is used for the preservation of jams.2. Developed preservatives:- During certain processes some products can bedeveloped which act as preservatives. The products are called developedpreservatives, for example during fermentation acid is produced in foods whichact as a preservatives.

3. Artificial preservatives:- The synthetic chemicals that are used for thepreservation of food are called artificial preservatives. For example sodiumbenzoate, citric acid are artificial preservatives.

5. Write the effects off consumption of spoilt foods.Ans. The effects of consumption of spoilt foods are:-1. The intensity of effect will depend on the type and number of micro organisms and consumers power.2. It may also cause food poisoning which may cause certain disease due toingestion of toxic substances produced by micro organisms.

3. There may be an infection produced by pathogenic micro organisms carriedby the food. Sometimes this pathogenic micro organisms may produce sometoxins.4. There may be gastro intestinal disturbance. Such as nausea, abdominalpain, vomiting, diarrhoea. Other symptoms are headache, fever or chills,muscular weakness, drowsiness etc.5. Food poisoning may be a cause of death.

6. State how cleanliness of food handlers should be maintained.Ans. The cleanliness of food handlers should be maintained by the followingways.1. Food handlers should be free from any communicable diseases.2. They should maintain a high standard of personal hygiene.3. They should undergo regular medical check up.4. They should wear clean clothes.5. They should avoid coughing, sneezing and spitting while at work.6. They should avoid smoking or chewing of tobacco.7. They should not touch his body parts such as hair, legs, feet while handling thefood.


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7. Explain why food should not be exposed to moist air?Ans.1. If food is exposed to moist air, number of micro organisms contaminate it.2. They start multiplying itself.3. They decrease the nutritive value of food.4. Micro organisms release some toxic substances and make food unfit for consumption.Hence food should not be exposed to moist air.

8. Explain what happens when meat is overcooked with a pinch of sodiumbicarbonate.

Ans. When meat is overcooked with a pinch of sodium bicarbonate, vitamins of Bcomplex and vitamin present tin meat get destroyed. As a result of this, thenutritive quality of the food is affected. The meat is disintegrated and loss itscolour and flavour.

9. Explain, why fishes should not be used as food without salting?Ans.1. Salting of fishes is done to prevent its spoilage.2. Salting of fishes is also done for preservation for a longer time.3. If fishes are kept for a longer time they become stale and get contaminated.4. Use of such contaminated fishes is harmful. Therefore, fishes should not be

used as food without salting.


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HUMAN HEALTH AND DISEASESQ1. Give Scientific reasons:-

1. Albino persons cannot synthesize the pigment melanin.

Ans. Albino persons cannot synthesize the pigment melanin because.1. It is hereditary disease in which there is no pigmentation of hair, eyes andcolour of the skin.2. The gene, which controls the synthesis of the pigment melanin, undergoesmutation in them.

2. In take of saturated fat should be avoided.Ans. Intake of saturated fat should be avoided because1. Saturated fat contains cholesterol and triglycerides in them.2. Excess intake of saturated fats leads to deposition of these fats on the inner walls of the arteries causing arteriosclerosis.

3. It also increases the chance of heart attack.3. In India, the causes of heat attacks are increasing.Ans. In India, the cause of heart attacks are increasing due to increased mentaland physical stress and strain on the people.Both mental and physical stress and strain have adverse effects on the heartcausing heart attacks.

4. There is oedema on the body during kidney failure.Ans. There is oedema on the body during kidney failure because1. Kidney failure is the malfunctioning of kidneys.

2. There is accumulation of poisonous substance and water in body.3. Accumulation of water in the tissues leads to swelling called oedema.

5. The people should be educated to avoid cancer and AIDS.Ans. The people should be educated to avoid cancer and AIDS because they arethe leading cause of mortality in developed countries.

6. Cancer cannot be diagnosed in its early stage.Ans.1. Cancer is one of the leading cause of mortality in developed countries.2. There is no early warning symptoms such as pain or fever. Hence, cancer cannot be diagnosed in its early stage.


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HUMAN HEALTH AND DISEASES7. Vehicle drivers are tested for colour blindness before issuing license.Ans.1. Colour blindness is a hereditary disease.

2. Colour blind persons cannot distinguish between different colours.3. Most common colour blindness is for red and green colour.4. This defect is usually observed in males. Hence, vehicle drivers are tested for colour blindness before issuing license.

8. Blood sugar level increases in diabetes.Ans.1. Diabetes may be due to metabolic disorder as well as organic failure and itscan be hereditary.2. It is the defective functioning of the beta cells of islets of Langerhans inpancreas which secrets the hormone insulin.

3. In absence of this hormone, the tissues, especially liver tissues fail to utilizeglucose. This, results increased blood sugar level in diabetes.

Q2. Define

1. Communicable disease :- Diseases that are caused due to pathogens andare transmitted from one person to another are called communicable diseases.Diseases such as influenza, cholera, tuberculosis are communicable diseases.

2. Non communicable disease:- Diseases that are caused due to factorsother than pathogens and are not transmitted from one person to another are

called non communicable diseases. Diseases such as cancer and diabetes arenon communicable diseases.

Q3. Answer the following in short:-

1. List the carcinogenic factor (or) Name the factor which increases the riskof caner. Suggest the treatment of cancer.Ans. Factors such as smoking, exposure of radiation, some chemicals, foodstuffs and dyes may increase the risk of caner. These factors are calledcarcinogenic factors as they cause cancer.The Treatment of caner are1. Radiotherapy. 2. Chemotherapy. 3. Surgery.


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HUMAN HEALTH AND DISEASES2. Write a note on kidney failure.Ans.1. Malfunctioning or defective functioning of the kidney is called kidney failure.

2. It is due to infection of physiological disorders.3. It leads to accumulation of poisonous substances in the tissues causingoedema.4. Urea in the blood increases, which leads to uremia.

3. What are the four types of heart diseases?Ans. The four types of heart diseases are as follows.1. Congenital defect2. Rheumatic fever.3. Coronary diseases.4. Excessive strain on the heart.

4. Name the hormone secreted by the thyroid gland. Write down threeaffects due to excess secretion.Ans. 1.The hormone secreted by the thyroid gland is thyroxine.2. Effects due to excess secretion of thyroxine is increased metabolic rate,hyperactivity, loss of weight and protruding eyeballs.

5. Write the symptoms of diabetesAns. They symptoms of diabetes are as follows.1. Excess of throat.2. Hunger

3. Frequent urination4. Loss of weight with general weakness

6. Suggest any four measures to control diabetes.Ans. The four control measures to control diabetes are as follows.1. Restriction of sugar intake.2. Injections of insulin3. Consumption of hypoglycemic substances4. Regular exercise can control diabetes.

7. Name any four diseases caused by polluted water.Ans.

1. Jaundice2. Cholera3. Typhoid4. Gastroenteritis


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HUMAN HEALTH AND DISEASESQ4. State the effect of the following

1. Effect of X rays on health:- They show adverse affects on cell growth and

interfere with the genetic constitution and metabolic activities.

2. Effect of air pollutants on human health :- They cause lung disorders. Theyalso cause headache, irritation of eyes and nose, coughing, breathlessness,chest pain and bronchial asthma.

3. Effect of water pollutants on health:- Water pollutants cause disease like jaundice, cholera, typhoid and gastro enteritis.

4. Effect of deficiency of iodine on health :- Deficiency of iodine causes goiter i.e. enlargement of the thyroid gland.

5. Effect of mental and physical strain on health:- Mental and Physical straincause mechanical strain on the heart, resulting into heart diseases.

6. Effect pf consumption of saturated fats on health:- Consumption of saturated fats causes arteriosclerosis, which results in heart attack.

Q5. Describe the following heart diseases:-

1. Congenital heart diseases:-1. The congenital heat diseases are mostly due to malfunctioning of the valves in

the heart.2. Congenital heart diseases may also be due to the presence of a hole in theseptal wall of the heart which causes the mixing of oxygenated and de oxygenated blood in the heart.3. The main causes of congenital heart diseases are as follows:-

i. Infections like German measles in the pregnant mother.ii. Administration of pregnancy.iii. Exposure to radiations like X rays which may affect the embryo.

2. Rheumatic fever:-1. Rheumatic fever is an inflammatory disease caused by the infection by a strainof streptococcus.2. Rheumatic fever affects the heart.3. Rheumatic fever is usually seen in the population living in cold and humidclimate in overcrowded areas where the condition are unhygienic.


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HUMAN HEALTH AND DISEASES3. Coronary diseases:-1. Coronary diseases of heart and caused by the intake of fats, especiallysaturated fats in the diet.

2. The cholesterol from the fats gets deposited on the wall of the artery supplyingblood to the heart.3. Owing to the deposition of cholesterol on the wall of the artery, its lumenbecomes narrow resulting into less supply of blood to the heart. This disease iscalled arteriosclerosis.4. Arteriosclerosis may cause heart attack.5. Coronary diseases are observed in the people able the age of 45 years.6. Males are more prone to coronary diseases.

Q 6. Explain the following:-

1. Health:-1. Health literally means sound condition of the body.2. It is a state of physical, mental and social well being and not merely theabsence of disease.

2. Disease:-1. The word disease (dis ease) means uneasiness. i.e. departure from a stateof normal health.2. Disease is a condition in which the normal state of mind, body and well beingperson is impaired.3. A disease is diagnosed from the symptoms which it produces.

3. Haemophilia:-1. Haemophilia is a hereditary disease caused by mutation of the gene whichcontrols the clotting blood.2. In Haemophilia the blood does not clot. Therefore, a person suffering fromHaemophilia may bleed to death when injured.3. Haemophilia is usually found in males. It is rarely seen in females.

4. Albinism:-1. Albinism is a hereditary disease.2. A person suffering from albinism cannot synthesize the pigment melanin.Therefore, his skin, iris of the eyes, eyelashes and hairs on the body appear white.3. Albinism is caused by the mutation in the gene which controls the formation of the pigment melanin in the body.4. A person showing albinism is known as albino.5. Albinos develop rashes on their skin i

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