icse class 9 geography book pdf

ICSE Solutions for Class 9 Geography – Humidity

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Exercises

I. Short Answer Questions.

Question 1.
Define the following terms :

(a) Precipitation
(b) Evaporation
(c) Condensation
(d) Humidity
(e) Latent heat.

Answer:

(a) Precipitation — It is process by which condensation in different forms falling on the ground e.g. rainfall, snowfall, drizzle, sleet and hail etc.
(b) Evaporation — It is the process of converting water into water droplets and vapour.
(c) Condensation — It is the process of converting the water- droplets into water.
(d) Humidity — It is the amount of moisture present in the atmospheric air.
(e) Latent heat — It is the unseen heat absorbed by the atmospheric air to form vapour after reaching boiling point of 100°C of water.

Question 2.
What determines the amount of water vapour in the air?
Answer:
The amount of water vapour or humidity is dependent on the temperature conditions, because the capacity of air to hold moisture changes according to the temperature, e.g., in higher temperature the water vapour amount may increase and in low temperature it may decrease.

Question 3.
How is relative humidity determined ?
Answer:
Relative humidity is the percentage of water vapour with respect to the amount of air at a particular temperature.

Question 4.
Name four chief forms of condensation.
Answer:
Four chief forms of condensation are clouds, fog, mist and dew droplets.

Question 5.
Mention the different forms of precipitation.
Answer:
Different forms of precipitation are rainfall, drizzling, hailstones, snowfall and sleet etc.

Question 6.
What do you understand by ‘condensation nuclei’ ?
Answer:
Condensation nuclei — Condensation nuclei is the base around which moisture is gathered and converts into a drop of water, e.g. the dust particles present in the atmosphere make the base of condensation form.

Question 7.
State the three types of rainfall.
Answer:

• Relief Rainfall – It occurs from the cooling of warm moist air which ascends above the mountain barrier lying in the direction of the prevailing winds.
• Cyclonic or Frontal Rainfall – It occurs when warm and cold air masses confront each other, the warmer air generally climbs above the colder air.
• Convectional Rainfall – Ascending currents of hot and humid air causes condensation of the clouds, resulting in heavy rainfall.

Question 8.
What is cyclonic rainfall ?
Answer:
Cyclonic rainfall is provided by the cyclones created in tropical and temperate regions along the air mass fronts, where warm and cold air meet together and the warm air is encircled by the cold air resulting in circular wind systems. The tropical cyclones provide heavy rainfall for a few days, but temperate cyclones provide light rainfall or drizzling for a long period.

Question 9.
How does latitude affect evaporation ?
Answer:
Evaporation is highest in the tropical belt due to continuous vertical rays of the sun, while in temperate belt less evaporation and in polar belt least evaporation takes place due to less insolation.

Question 10.
Why is evaporation maximum in tropical deserts surrounded by seas ?
Answer:
In tropical deserts, surrounded by seas, evaporation is maximum because of high temperatures and clear skies.

Question 11.
State the factors favouring evaporation.
Answer:
The conditions favourable for evaporation are high temperature and large amount of water of ocean, rainfall water etc.

Question 12.
What is the instrument used for measuring humidity?
Answer:
Hygrometer or Dry and Wet Bulb Thermometer is used to measure humidity.

Question 13.
State the process of clouds formation. Name the types of clouds.
Answer:
When the water vapour converts into the water droplets floating in the air, the clouds are formed. Main types of clouds are Cirrus, Cumulus, Altus and Stratus.

Question 14.
Name the regions which receive rainfall only in summer.
Answer:
The continental interiors in the sub-tropical regions get rainfall only in summer, e.g. Mangolia, Tibet etc.

Question 15.
Name two regions of heavy rainfall.
Answer:
Equatorial region and monsoon tropical region get highest rainfall. Highest rainfall is recorded in Cherrapunji and Mawsynram (1080 cm) in the world.

Question 16.
Describe the three chief ways in which condensation occurs.
Answer:
Three chief ways to assist condensation are :

1. High amount of moisture present in atmosphere.
2. The elements providing the nuclei for it should be present in atmosphere, e.g., dust particles, salt and smoke etc.
3. The air should be saturated i.e. the relative humidity must be 100% to create dew point or the temperature should be below dew point.

II. Give reasons for each of the following 

Question 1.
In Equatorial regions the sky often remains overcast with clouds.
Answer:
Due to excessive heat the evaporation takes place in fast speed, and in every afternoon rainfall occurs after heavy cloud formation by convection process. So the sky mostly remains overcast with clouds.

Question 2.
Human comfort depends on humidity.
Answer:
Human efficiency is best at 40% relative humidity. More or less humidity creates uneasiness of humidity and dryness.

Question 3.
Condensation is the reverse process of evaporation.
Answer:
Condensation takes place upto the dew-point comes, but after it precipitation starts due to water-droplets converted into water drops. So, condensation and precipitation are different processes occurring in different conditions and temperature episodes.

Question 4.
Coasts receive more rainfall than the interior of the continents.
Answer:
Moisture-laiden winds provide more rainfall to the coastal parts due to being situated by the coast and receiving the rain bearing winds, but the interior get negligible rainfall due to being the almost dry winds without moisture.

Question 5.
The windward sides of mountains receive more rainfall than the leeward sides.
Answer:
The windward sides of mountainous slopes get ample rainfall by striking with the rain bearing winds first, while the leeward sides cannot get sufficient rainfall due to being on other side where the winds become almost dry due to imparting rainfall in windward due to loss of major part of moisture and water drops.

III. Match the following

Answer:

IV. Long Answer Questions.

Question 1.
Distinguish between Absolute Humidity and Relative Humidity.
Answer:
Absolute Humidity :

1. It is the measure of the actual amount of water vapour in the air, regardless of temperature.
2. It is expressed as grams of moisture per cubic meter of air(g/m3).
3. The higher the amount of water vapour, the higher is the absolute humidity.
4. In weather calculations, absolute humidity is generally not taken into account.

Relative Humidity:

1. It measures water vapour in air but relative to the maximum vapour that the air can hold at that temperature.
2. It is expressed as the ratio (percentage value) between the absolute humidity of a given mass of air and the maximum amount of water vapour that it can hold at the same temperature.
3. Warm air possesses more water vapour than cold air, so with the same amount of absolute humidity, air will have a different relative humidity depending on temperature.
4. It is the essential characteristic of weather forecasts, which indicates the likelihood of precipitation, dew or fog.

Question 2.
With reference to condensation, define the following :

(a) Process of condensation.
(b) Atmospheric conditions that favour condensation.
(c) Forms of Condensation.

Answer:

(a) Condensation is the reverse process of evaporation. In condensation, water vapour in the atmosphere get converted into water droplets or ice. Condensation takes place when water vapour is added to saturated air or when the temperature falls below the temperature at which air become saturated.
(b) The atmospheric conditions that favour condensation are :

1. There should be a high amount of water vapour present in atmosphere.
2. Minuscule particles of dust, salt and even smoke act as condensation nuclei.
3. The temperature of air must be below dew point temperature so as to encourage condensation.

(c) Forms of condensation : Following are the forms of the

• condensation : Dew, frost, fog, mist, white frost and clouds. The clouds are formed when the temperature falls down below dew points, while dew, fog and clouds are formed when the temperature remains higher than the freezing point.
• Clouds : Clouds are formed when minute droplets of water vapour condense on a nuclei and remain suspended in air.
• Dew : When water vapour condenses on the surface, it forms tiny droplets of water called dew. Dew commonly occurs during winter on account of cooling of air below dew point.
• Frost : In very low temperature, when condensation occurs at zero metre or ground level, water vapour freezes into minute crystals of rice on objects near the ground such as blades of grass, leaves and tiny rock particles. Frost is harmful to plants.
• Fog and Mist : Fog and Mist are two related terms. Droplets of water suspended in the atmosphere close to the surface of the earth are termed as fog. On long winter nights, the ground cools more rapidly than the air above. Such cooling reduces temperature at the surface to below dew point. Water vapour at lower levels get condensed around minute solid particles to form fog.

PQ. Describe the process of evaporation together with factors that favour it.
Answer:
For evaporation excessive heat and presence of water bodies is essential. Nearly 600 calories of heat is required to change water into water vapour. Evaporation is maximum in tropical belt and mainly in hot desert region surrounded by water bodies. In the equatorial belt, due to overcast with clouds, evaporation is comparatively less due to obstacles of cloud in heating process.

Question 3.
Name the three types »of rainfall. With the help of a diagram describe each type of rainfall.
Answer:

1. Convectional rainfall : It occurs in the Equatorial regions. The high temperature leads to the rapid heating of air. Such heated air rises in convectional currents, leading to development of clouds at about 10 km height. Ascending currents of hot and humid air causes condensation of the clouds, resulting in heavy rainfall.
   
2. Relief Rainfall : Relief rainfall is also known as Orographic Rainfall. It occurs from the cooling of warm moist air which ascends above the mountain barrier lying in the direction of the prevailing winds. The presence of mountains causes humid jair to rise. The sudden ascent causes cooling of air, leading to condensation and precipitation.
   
3. Cyclonic Rainfall : This type of rainfall is due to cyclones and depressions. When warm and cold air masses confront each other, the warmer air generally climbs above the colder. The rising air is cooled while undergoing a frontal lift. This causes precipitation.
   

Question 4.
Define precipitation. Write short notes on three forms of precipitation.
Answer:
The process by which products of condensation, viz water droplets, ice crystals, sleet, etc., fall to ground is known as precipitation. Rainfall, snowfall, drizzle, sleet and hail are the chief forms of precipitation. Precipitation takes place only when they particles of water join together to form large sized particles which become too heavy to remain in suspension in the cloud.

1. Rain : It is the most common form of precipitation. Raindrops of smaller size and less intensity are known as drizzle.
2. Dew : When water vapour condenses on the surface, it forms tiny droplets of water called dew. Dew commonly occurs during winter on account of cooling of air below dew point.
3. Frost : In very low temperature, when condensation occurs at zero metre or ground level, water vapour freezes into minute crystals of ice on objects near the ground such as blades of grass, leaves and tiny rock particles. Frost is harmful to plants.

Question 6.
Make a brief survey of the world distribution of rainfall.
Answer:
Equatorials and coastal areas of monsoon countries get maximum rainfall, more than 200 cm, sub-tropical areas get moderate rainfall 100-200 cm, and the least rainfall areas are Hot and cold deserts getting nearly 25 cm.

ICSE Solutions for Class 9 Geography – Pollution

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Exercises

I. Short Answer Questions

Question 1.
What is environmental pollution ?
Answer:
Environmental pollution refers to any unfavourable alteration of our surroundings, wholly or largely as a by product of man’s actions. These changes may affect man and other organisms.

Question 2.
Give the definition of a pollutant.
Answer:
A pollutant is a product released into the biosphere disturbing the normal functioning of ecosystem due to its adverse effect on plants, animals and man.

Question 3.
Give the difference between natural and man-made pollutants.
Answer:
Natural pollution takes place by increasing the quantity of Carbon dioxide and Nitrogen oxide in the atmosphere but man made pollution is done by using pesticides, chemical fertilizers.

Question 4.
What is air pollution ? Give a source of air pollution.
Answer:
Air pollution is the excessive concentration of foreign matter in the air which adversely affects the well-being of human beings, animals, plants and their environment. Air pollution is caused by addition of chemicals, carbon monoxide, sulphur dioxide, hydrogen sulphide by various factories, industrial plants.

Question 5.
Define water pollution.
Answer:
Water pollution is caused by contamination of water by alteration in physical, chemical, biological characteristics of water making it unsuitable for designated use in its natural state.

Question 6.
What is soil pollution ?
Answer:
Soil pollution is defined as the change in physical, chemical and biological conditions of the soil through man’s intervention resulting in degradation in quality and productivity of soil.

Question 7.
Why should we avoid soil pollution.
Answer:
Soil is the basic need of agriculture. If the soil is polluted, the crops will be harmful for health and quality.

Question 8.
What is radioactive pollution ?
Answer:
Radioactive pollution is done by cosmic radiation from space, terrestrial radiation from radio-isotopes from earth’s crust, nuclear fuels in atomic plants, atomic bombs etc.

Question 9.
What is noise pollution ? What harm does noise pollution do to human beings ?
Answer:
Noise pollution is done by extreme noise done by industrial sector, transport, loud speakers etc., which adversely affect human health causing severe headache, migraine, mental disbalance, nervous breakdown, heart diseases.

Question 10.
Give the difference between biodegradable and non- biodegradable pollutants.
Answer:
Biodegradable pollutants are degraded by microbial actions e.g. sewage, garbage etc, but non-biodegradable pollutants are not degraded e.g. glass, plastics etc.

Question 11.
Distinguish between each of the following :
(i) Biodegradable and Non-biodegradable Pollutants
Answer:
Biodegradable Pollutants :

1. These may be degraded ‘‘after sometime by biological or microbial actions.
2. These are sewage, domestic garbage of kitchen etc.

Non-biodegradable Pollutants :

1. These are not degraded by any biological or microbial actions.
2. These include plastics, pesticides and radioactive materials.

(ii) Quantitative Pollutants and Qualitative Pollutants.
Answer:
Quantitative Pollutants :

1. The excess of CO₂, Nitrogen oxide etc. pollute the atmosphere.
2. These create unhealthy atmosphere due to the scarcity of oxygen.

Qualitative Pollutants :

1. Use of pesticides, chemical fertilizers pollute the composition of atmosphere.
2. These result in various diseases, e.g. skin cancer asthma etc.

(iii) Natural Pollution and Anthropogenic Pollution.
Answer:
Natural Pollution :

(a) Cosmic radiation from space and terrestrial radiation pollute the atmosphere.
(b) It disturbs the natural atmosphere and harms human and animal life.

Anthropogenic Pollution :

(a) Man-made pollution is done by radioactive plants, atomic bombs, nuclear fuel etc.
(b) It creates various diseases cancer, heart problems, migraine etc, it also disturbs animal life.

II. Long Answer Questions

Question 1.
With reference to pollution, explain the following

(a) Air pollution
(b) Water pollution

Answer:

(a) Air pollution is the excessive concentration of foreign matter in the air which adversely affects the well-being of human beings, animals, plants and their environment. Air pollution is caused by addition of chemicals, carbon monoxide, sulphur dioxide, hydrogen sulphide by various factories, industrial plants.
(b) Water pollution is caused by contamination of water by alteration in physical, chemical, biological characteristics of water making it unsuitable for designated use in its natural state.

Question 2.
Explain clearly what is radioactive pollution. Why is radioactive pollution more harmful than other types of pollutions ?
Answer:
Radioactive pollution is caused by cosmic radiation from space, use of radioactive materials which are used in radioactive weapons, nuclear fuel and electric power.
Radioactive pollutants remain unperished for a long period, so these are more harmful to spoil natural environment. In t modem age, it has become very difficult to survive in natural state due to production of various radioactive materials for various purposes.

Question 3.
How is noise a source of pollution ? Why do we need to look at the problem of noise pollution seriously ?
Answer:
Noise is a source of pollution because noise pollution is done by extreme noise of industrial sector, transport, loud speakers etc., which adversely affect human health causing severe headache, migraine, mental disbalance, nervous breakdown, heart diseases.
Noise is a health hazard. Exposure to prolonged noise has many physical, physiological and psychological effects on human beings in the following ways:

1. repeated exposure to noise reduces the sleeping hours
2. productivity or efficiency of a human being
3. it affects the peace of mind and invades the privacy of a human being.

Question 4.
How are the pollutants categorised on the basis of their existence in nature. Give two examples of each category?
Answer:
Pollutants are categorises in mainly i.e. degradable and non- degradable pollutants, out of them non-degradable pollutants create problem of pollution, e.g. glass, plastics, pesticides etc.
On the basis of existence in nature, pollutants are divided into two categories:

• Quantitative pollutants : These substances exist in nature but they act as pollutants when their concentration or quantity increases up to a critical level in the atmosphere, e.g., Carbon- dioxide, Nitrogen oxide, etc.
• Qualitative pollutants : These pollutants do not exist in environment They are introduced into the environment through man’s activities, e.g., pesticides (DDT), chemical fertilizers, herbicides etc.

Question 5.
Explain with examples the difference between the primary and secondary pollutants.
Answer:
Primary pollutants are directly mixed with atmosphere e.g. smoke, ash, fumes, dust, CO₂ Sulphur dioxide Methane, Benzene etc. Secondary pollutants are created by automobiles e.g. Nitrogen oxides, hydrocarbons etc, which are more toxic than their original elements.

Question 6.
What is noise pollution ? How is it caused ?
Answer:
Noise pollution is defined as an unwanted sound that is an irritant and a source of stress.
Most of the noise originates from modem industrialised urban life. The main sources of noise pollution are :

1. Industrial Sector
2. Transport Sector
3. Household sector
4. Defence Sector
5. Loud Speakers
6. Miscellaneous Sources.

ICSE Solutions for Class 9 Geography – Sources of Pollution

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Exercises

I. Short Answer Questions

Question 1.
Name any three air pollutants and the sources of each of them.
Answer:
Pollutant :

1. Carbon Monoxide (CO) :
2. Nitrogen Oxides (NO_x) :
3. Sulphur Oxides (SO_x) :

Sources :

1. Gasoline fuel, motor vehicles fuel, burning of wood and coal, solid waste disposal, Industrial processes.
2. Primary sources are motor vehicles and power generation stations, combustion of organic matters, furnace stacks, incinerators.
3. Mainly due to burning of coal, smelting operations, refineries, chemical plants, open burning of garbage and municipal incinerators.

Question 2.
What are natural sources of air pollution ?
Answer:
Natural sources are volcanic eruptions, sand, dust, forest fires etc.

Question 3.
Name one industry which pollutes the atmosphere with gaseous as well as with particulate matter.
Answer:
Automobile industry.

Question 4.
What is known as smog ? What harm is done by smog especially in winter ?
Answer:
Smog means smoke + fog. In winter season smog is responsible for many accidents due to the obstacle in visibility.

Question 5.
Name three gases emitted during burning of garbage.
Answer:
These are Carbon dioxide, Sulphur dioxide, Nitrogen oxides.

Question 6.
Mention any two sources of water pollution.
Answer:
Two sources of water pollution are :

• household detergents and sewage,
• oil spills

Question 7.
Name two heavy metals from industries that pollute water.
Answer:
Heavy metals are Lead and Mercury.

Question 8.
Mention any four sources of soil pollution.
Answer:
These are industrial wastes, domestic waste, chemical fertilizers and pesticides.

Question 9.
Why are radioactive pollutants very dangerous ?
Answer:
The emission of radioactive minerals Uranium 235 Plutonium 239, make the whole surroundings radioactive after fission and carried away by wind to long distances. These are dangerous to health, as these remain as it is for a long time.

Question 10.
What kind of solid and liquid pollutants does the offshore drilling produce ?
Answer:
Drilling produces dust, stones etc and crude oil spills pollute largely the oceanic water and disturb marine life.

Question 11.
What are primary pollutants ?
Answer:
The pollutants that are directly emitted from the sources and are found in the atmosphere in the form in which they are emitted are known as primary pollutants, e.g., ash, radioactive compounds, oxides of sulphur and nitrogen etc.

Question 12.
With an example, state what are secondary pollutants?
Answer:
The pollutants that are formed in the atmosphere by chemical interactions between primary pollutants and atmospheric constituents are known as secondary pollutants. Examples of secondary pollutants are Sulphur trioxide, Ozone, Peroxyacetyl Nitrate (PAN), Ketones etc.

Question 13.
What is the connection between urbanisation and air pollution ?
Answer:
The major connection between urbanisation and air pollution are automobiles, industries, burning of garbage and brick kilns. These sources release pollutants such as oxides of carbon, oxides of sulphur, oxides of nitrogen, and hydrocarbons, ozone, chlorofluoromethanes, etc.

Question 14.
How much are the automobiles responsible for air pollution ?
Answer:
Automobiles are mainly responsible for 80% air pollution, emitting Carbon monoxide, Hydrocarbons, Nitrogen monoxide etc.

Question 15.
How are brick kilns a source of gases and particulate matter that cause air pollution ?
Answer:
Brick kilns produce huge amount of Carbon oxides, smoke and dust etc.

II. Long Answer Questions :

Question 1.
With reference to noise pollution, answer the following:

1. How does traffic contribute to noise pollution ?
2. Why are the construction sites considered as worse than factories in their contribution to noise pollution ?
3. How do the airplanes cause noise pollution ?

Answer:

1. The increasing number of vehicles on the roads are a big source of noise pollution. Increasing traffic jams in congested areas lead to repeated hooting of horns by impatient drivers causing noise pollution.
2. Noise from construction sites is generally far worse than noise originating from factories. This is because whatever construction takes place noise emissions levels are higher as well as the equipment is inherently noisy.
3. Noise pollution caused by airplanes has been increasing steadily during recent years, especially in the areas close to international airports. This problem has mainly arisen because of the widespread use of heavy long-range jet aircraft. Noise made by jet planes is more disturbing than that of the old propeller driven aircraft because it is of far higher pitch. Jet noise is caused by the violent mixing of the jet of gases from the engine with the surrounding air. It is at maximum level during take-off when the engine delivers maximum thrust, and falls away rapidly as the aircraft climbs. During landing, the main source of high-frequency noise is the sound made by the air compressor and turbine blades. Aircraft pass close to the ground for quite a distance during the landing operation and this noise often constitutes a more sustained environmental nuisance than the intense noise of shorter duration produced during take-off.

Question 2.
Air pollution is the contamination of air by pollutants. In this context answer the following :
(i) How does the use of automobiles cause air pollution ?
Answer:
Automobiles produce large amount of CO, hydrocarbons, oxides and suspended particulate matter and cause air pollution.
(ii) Write short notes on industrial air pollution.
Answer:
Industrial pollution cannot be avoided, as without it development is not possible. So it is an unavoidable problem faced by urban industrial areas, because harmful gases, garbage etc. is emitted by industrial activities, e.g. Industries release CO, oxides of Sulphur and Nitrogen, smoke, dust etc. to the air.
(iii) What special kind of air pollution do the brick kilns produce?
Answer:
Dust and smoke are the main elements produced by the brick kilns to pollute the air.

Question 3.
With reference to the sources of water pollutants answer the following questions:
(i) Why is it harmful to dispose of household detergents in water bodies ?
Answer:
Detergents contain some phosphates which are helpful to 1 produce algae and aquatic weeds which pollute the water.
(ii) In what way does the industrial waste pollute water?
Answer:
Many harmful wastes are produced by the industries which ; pollute water, e.g. Kanpur leather works continuously are polluting water of Ganga river creating a big problem. Industrial wastes mixed with water make it poisonous and unhygenic and may result in various diseases.
(iii) How do the radioactive wastes get into the water bodies?
Answer:
Wastes produced by nuclear power stations nuclear weapons / testing, research laboratories, and hospitals, are the main radioactive wastes which pollute the water bodies.
(iv) How is the thermal pollution of water caused ? What are its effects ?
Answer:
The thermal power plants located near the rivers use water for cooling purposes. They release the recycled hot water into the rivers leading to thermal pollution. The hot water makes the temperature of aquatic environment rise which endangers the aquatic ecosystem.

Question 4.
Write short notes on soil pollution by

(a) Pesticides
(b) Biomedical waste.

Answer:

(a) Pesticide waste mixed with the soil make it harmful for natural composition of soil and natural plants which cannot be taken in food material due to toxic material and the soil is contaminated for a long time.
(b) Biomedical waste Hospital wastes contain organic materials, chemicals, metal, needles, plastics contaminate the soil and make it unfit for growth of plants etc. Third world countries are facing this problem deeply.

Question 5.
What are the sources of radioactive pollution ? Describe each of them.
Answer:
These are natural sources from cosmic rays, man-made sources by use of  X-rays, nuclear weapons, Atomic reactors and fuel, radioactive isotopes in research laboratories are the main reasons to pollute rivers, streams and lakes etc. through sewers.

Question 6.
What are the man-made sources of air pollution ?
Answer:
Man-made sources are human activities, e.g., industries, factories, urban settlement, aircraft, nuclear experiments, automobiles, agricultural and power plants etc. are the sources of air pollution.

ICSE Solutions for Class 9 Geography – Effects of Pollution

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Exercises

I. Short Answer Questions.

Question 1.
How does noise pollution affect animals ?
Answer:
Noise from industries, railways, crackers, explosions and commotion in the cities and aircraft, affect animals, birds, mice, fishes and domestic animals. Birds avoid migrating to places where noise level is above 100 dB. The noise emissions caused by supersonic aircraft and railways may cause miscarriage in mammals and fishes as well. Some of the birds have been found to have stopped laying eggs due to noise pollution

Question 2.
What major harm is done to the human beings by air pollution ?
Answer:
It causes irritation in eyes, nose, throat, asthma etc, headache, slurring of speech, lung cancer, damage to nerves, brain fiver and kidneys.

Question 3.
How are the animals affected by air pollution ?
Answer:
Polluted grass is eaten by the animals cause arsenic poisoning. Lead poisoning results in bronchitis and lack of appetite in pet animals.

Question 4.
What is the effect of oil spills on marine life ?
Answer:
Sea water polluted with oil leakage causes oil spills which contaminate sea water and lead to the death of marine organisms.

Question 5.
What causes waterborne diseases ? Name two waterborn diseases.
Answer:
Phosphates and Nitrates from fertilizers, industrial effluents e.g. Arsenic, Mercury, Cadmium, Lead etc. Gastrointestinal problems, typhoid etc.

Question 6.
In what way does soil pollution affect human beings?
Answer:
Human beings are affected through food chains e.g. Nitrogenous fertilizers produce toxic concentration of nitrate and nitrite in the leaves through soil, pollution of soil by underground water polluted by industrial wastes. Eutrophication causes pollution of water and soil making it infertile and unsuitable for plant growth.

Question 7.
Give the impact of radiations on the human body.
Answer:
Damage is caused to the offsprings and organs of the body. Several diseases are caused e.g., breast cancer, thyroid cancer, lung cancer, brain cancer and defective eye sight.

Question 8.
Why are nuclear radiations more dangerous than other forms of pollution ?
Answer:
Nuclear radiations survive for a long period upto hundred years resulting in widespread effects to pollute the natural environment.

Question 9.
What caused the Bhopal gas tragedy ?
Answer:
This was the worst industrial accident on December 3 1984, when about 40 tons of methyl isocyanate (MIC) leaked into the atmosphere from Union Carbides pesticide factory in Bhopal in Madhya Pradesh.

Question 10.
What caused the Chernobyl disaster ?
Answer:
This was a radioactive accident in 1986 in Chernobyl in Ukraine on April 26. When a reactor of nuclear power complex at Chernobyl exploded. A massive steam explosion, the core of the reactor combined with water to produce hydrogen exploded blowing toxic radioactive gases into the air.

Question 11.
What were the after-effects of the Bhopal gas tragedy?
Answer:
The tragic after effects were blinding people, choking their breathing and suffocating them, damaged the eyes, lungs and nervous system, upset the urine system and loss of unborn babies, different plant species were also damaged.

II. Long Answer Questions 

Question 1.
Noise pollution is detrimental to human health and environment. Discuss.
Answer:
Noise pollution has ill effects not only on the human beings but also on the environment. Human Health

1. Effect on hearing or Deafness : Continuous exposure to noise levels above 100 dB has an adverse effect on hearing ability within a fairly short time. Many workers who are exposed to the noise of jet aircraft or very noisy workshops for even moderate periods soon develop detectable hearing defects.
2. Effect on Communication : External sounds can interfere with conversation and use of the telephone, as well as the enjoyment of radio and television programmes.
3. Repeated interference with sleep : Different people have different depths of sleep and they can adjust to natural sounds. However, noisy conditions near residential areas at night causes difficulties in sleeping.
4. Mental or Physiological Effects : Many people complain that noise makes them mentally ill. Experiments have been performed to attempt to confirm or disprove these claims. Doctors and scientists have now medically confirmed that *noise disturbs the biological organisms and their respective functions.
5. Effects on Physical health and Psychological problems : Noise has little physical effect on the biological performance provided that the noise level is below about 90 dB. Damage to the inner ear may result if continuous noise levels exceed about 100 dB and can lead to physical illness. Psychiatrists and psychologists have in recent researches made observations that noise has certain relation with physical health causing tension resulting in problems such as speech interference, annoyance, fatigue, sleep interference and emotional distress.
   Effects on Environment : The noise booms cause cracks in national and archaeological monuments Very high levels of noise are the cause of cracks in hills. High intensity explosions can break glass panes and vibrations in the buildings.

Question 2.
How does air pollution affect human beings and environment
Answer:
Air pollution affects human health in various harmful diseases e.g. irritation in eyes, headache, vomiting, respiratory disease, cancer, damage to liver and kidneys. SO₂ causes harm to plants by yellowing the leaves, NO₂ causes suppressed growth of plants. Animals eating the polluted grass are affected with arsenic poisoning.
Soot, dust and fumes discolour the fabrics arid buildings. The Taj Mahal has suffered damage caused by SO₂ in the air by getting discoloured and corroded. SO₂ and H₂SO₄ causes corrosion of metals like steel, copper and zinc.

Question 3.
Explain how the accumulation of nutrients and chemicals in the water prove fatal for the marine organisms.
Answer:
Eutrophication causes in growth of phytoplankton and algae which reduce the penetration of oxygen, light and heat into the water bodies, so, the marine organisms suffer greatly and mostly die.

Question 4.
Explain with the help of a diagram how the accumulation of toxic substances increases as we move up the food chain.
Answer:
Nitrogenous fertilizers produce toxic concentration of nitrate and nitrite in the leaves, which are eaten by animals and as ; vegetables by men, which is very harmful for health. Eutrophication is dangerous to marine life and the secondary consumers eating fish etc. are also adversely affected through complicated diseases. Harmful pathogens are transferred to human through vegetables and fruits.

Question 5.
Explain the effects of soil pollution on human beings and environment.
Answer:
Soil pollution causes contamination of plants which may affect the human health and the scarcity of oxygen disturbs the natural composition of air and air pollution promotes unwanted diseases.

Question 6.
Explain with examples the effects of radiations on the environment and on humans.
Answer:
Radiations emitting from radioactive materials and the disposal of radioactive wastes cause pollution and damage the environment. The high level products of nuclear wastes remain in the environment for several hundred years. Radioactive threats to the environment are the accidents connected with the activities of nuclear reactors, nuclear-powered vessels and satellites, etc. On human being it causes genetic variations, and somatic variation i.e. damage to body organs, breast cancer, thyroid cancer, lung cancer, brain cancer and defective eyesight.

Question 7.
What was the immediate and long term effects of the leakage of MIC gas from the Union Carbide’s pesticide factory in Bhopal ?
Answer:
This accident killed 3500 people and 40,000 people were affected in an area of 100 sq. km. Gas leakage did the people blind, loss of body control, loss of unborn babies, damage to brain, kidney, lungs, intestinal diseases, damaging the reproductive ability and plant species.

Question 8.
What harm did radioactive pollution do in the Chernobyl disaster ?
Answer:
After the disaster, four square kilometres of pine forest near the reactor turned reddish-brown and died. Horses also died 6 km. away by thyroid damage whole of western USSR and other European countries are contaminated by gamma emitters deposited on the soil. Meat and dairy products were contaminated with Caesium-137. About 7,00,000 people became exposed to Chernobyl radiation, expecting bad health problems.

Question 9.
What Is the impact of toxic compounds on human beings ?
Answer:
Toxic Compounds :

• Mercury, Methyl mercury
• Heavy metals, Cadmium
• Arsenic
• Fluoride

Impact on Human beings :

• ‘Minamata’ disease in Japan.
• ‘ltai-itai’ disease in Japan.
• Cancer, ulcers, kidney failure.
• ‘Fluorosis’ discolouring of teeth.

ICSE Solutions for Class 9 Geography – Preventive Measures

ICSE SolutionsSelina ICSE SolutionsML Aggarwal Solutions

Exercises

I. Short Answer Questions.

Question 1.
State two negative effects of vehicular emissions.
Answer:
Vehicular emissions have two negative effects on the environment : One is global climate change and the other is air pollution and its negative health repercussions.

Question 2.
Name any two gases emitted by vehicular emissions.
Answer:
Carbon monoxide (CO) and a large share of the hydrocarbonx (HC), nitrogen oxides (NO_x).

Question 3.
What is meant by carpooling ?
Answer:
Carpooling refers to the sharing of car journeys by persons travelling on the same route.

Question 4.
Name any three modes of public transport used in India.
Answer:
Buses, trams, passenger trains and metro rails.

Question 5.
What is a ‘No Smoking Zone’ ?
Answer:
Smoking does not just harm the smoker but also the people nearby, who breathe in the smoke exhaled by the smokers and are called ‘passive smokers’. Recent research has shown that concentration of second-hand tobacoo smoke (the smoke exhaled by smoekers) in many outdoor areas is often as high or higher than in some indoor areas and the risks posed by such outdoor exposure are well beyond generally ecceptd norms when large numbers of people are involuntarily exposed. Therefore, the passive smokers or those who unavoidably breathe in second-hand tabacoo at public places have such as lung cancer, asthma, bronchitis and sudden infant death syndrome in children.
To save such passive smokers and discourage smokers from the ill effect of the smoking in public places ‘No Smoking Zone’ has been created.

Question 6.
What are Fossil Fuels ?
Answer:
Fossil fuels refer to buried, combustible deposits of organic materials, formed from decayed plants and animals that have been converted to crude oil, coal and natural gas by exposure to heat and pressure in the earth’s crust over hundreds of millions of years.

Question 7.
State why should we use fossil fuels judiciously.
Answer:
Fossil fuels are non-renewable source of energy. As a result of growing demand fossil fuels are being depleted at a rate of 100,000 times faster than they are being formed. At the present rate of usage, the coal reserves are likely to last for about 200 years. Similarly, at the present rate of usage, the world’s crude oil reserves would be exhausted in just 50 years. These resources are non-renewable and take millions of years to form. It is essential, therefore, to reduce dependence on such energy resources and explore and exploit the enormous potential of alternative sources of energy like solar energy, tidal energy, wind energy, geothermal energy and biomass based energy. They are not only renewable sources of energy but are environmentally clean and safe to use.

Question 8.
State any three measures to save energy.
Answer:

1. Use extra blankets and sweaters instead of using room heaters. Likewise, in summer, dress in light, cotton clothes to save on air conditioning costs and energy.
2. Make sure that the houses are well insulated and, if heated or cooled, windows or doors are not left open. Raise shades on winter days, lower them in the summer. Seal all leaks. Block windows and doors with weather-strip tape and install blinds to reduce outside heat transfer.
3. Use a low-flow shower head, to reduce water consumption and energy usage to heat the water.

Question 9.
What is Organic Farming ?
Answer:
According to Food and Agricultural Organisation (FAO) “Organic agriculture is a unique production management system which promotes and enhances agro-ecosystem health, including biodiversity, biological cycles and soil biological activity, and this is accomplished by using on-farm agronomic, biological and mechanical methods in exclusion of all synthetic off-farm inputs”.

II. Long Answer Questions :

Question 1.
With reference to vehicular pollution in cities, state the significance of the following as a preventive measure.

1. Carpool
2. Public Transportation

Answer:

1. Carpool :
   (a) It reduces air pollution by reducing the number of vehicles on the road and thereby, cutting down the vehicular emissions.
   (b) It helps to save money in buying fuel and maintenance cost of cars.
   (c) It helps to save petrol and diesel and thereby, save foreign exchange that goes into buying these fuels.
   (d) It reduces traffic congestion on the roads and thereby prevents traffic jams, reduces fuel consumption and commuting time and the cost of road repairs.
   (e) It helps to use commuting time in useful pursuits.
2. Public Transportation :
   (a) It reduces damage to the environment by reducing emissions. For example, one bus emits far fewer fumes than 20 cars.
   (b) It requires 1/5 th energy per passenger per km compared to road based transport system. It therefore, reduces fuel consumption and thus helps to save foreign exchange used in buying petrol and diesel.
   (c) It causes less noise, no air pollution and is eco-friendly transport system.
   (d) It helps to save money spent on maintenance of personal vehicles. It avoids the need to find parking space for private vehicles. Thus, reduces congenstion on roads.

Question 2.
With reference to smoking, answer the following :

1. How does smoking harm passive smokers ?
2. Name any two legal provision meant to deter smoking.
3. State any three advantages of having a ‘No Smoking Zone’.

Answer:

1. Smoking does not just harm the smoker but also the people nearby, who breathe in the smoke exhaled by the smokers and are called passive smokers. Recent research has shown that concentration of second hand tobacco smoke in many outdoor areas is often as high or higher than in some indoor areas such outdoor exposure are well beyond generally are involuntarily exposed. Therefore, the passive smokers or those who unavoidably breathe in second-hand tobacco at public places have such as lung cancer, asthma, bronchitis and sudden infant death syndrome in children.
2. (a) As a preventive measure, a mandatory specific statutory health warning on cigarette packs was introduced in 1975. Realising the seriousness of the problem.
   (b) Smoking in public places was prohibited nationwide from October 2 under the Prohibition of smoking in Public Places Rules 2008. The smoking ban pertains to public places, which include auditoriums, cinemas, hospitals, public transport (aircraft, buses, trains, metros, taxis) and their related facilities (airports, bus stands, railway stations), restaurants, hotels, bars, pubs, amusement centers, offices, libraries, courts, post offices, markets, shopping malls, canteens, educational institutions and parks.
3. Advantages of No Smoking Zone are the following :
   (a) It reduces the possibility of second-hand tobacco smoke being inhaled by non-smokers.
   (b) It reduces air pollution. Areas which have prohibited smoking have been found to have better indoor air quality as opposed to areas where smoking is allowed.
   (c) It reduces healthcare costs by reducing the chances of diseases caused by smoking.
   (d) It reduces the chances of influencing others, especially the youth, to take on the habit of smoking.

Question 3.
With reference to Organic Farming state the following :

1. Four principles of Organic Farming.
2. Main characteristics of Organic Farming.
3. Importance of Organic Farming.

Answer:

1. The four Principles of Organic Farming are :
   (a) Organic should sustain and enhance the health of soil, plants, animals and humans as one and indivisible.
   (b) Organic farming should be based on living ecological systems and cycles, work with them, emulate them and help sustain them.
   (c) Organic agriculture should build on relationships that ensure fairness with regard to the common environment and life opportunities.
   (d) Organic farming should be managed in a precautionary and responsible manner to protect the health and well being of current and future generations and the environment.
2. The main characteristics of organic farming are the following :
   (a) Protecting the long term fertility of soils by maintaining organic matter levels, and creating optimized conditions for biological activity within the soil.
   (b) Providing crop nutrients indirectly using relatively insoluble nutrient sources which are made available to the plant by the action of soil micro-organisms.
   (c) Maintaining nitrogen self-sufficiency through the use of legumes and biological nitrogen fixation, as well as effective recycling of organic materials including crop residues and livestock manures.
   (d) Preventing weeds, disease and pests by relying primarily on crop rotations, natural predators, diversity, organic manuring, resistant varieties and limited (preferably minimal) thermal, biological and chemical intervention.
   (e) Providing attentive care and management of livestock, paying full regard to their evolutionary adaptations, behavioural needs and animal welfare issues, with respect to nutrition, housing, health, breeding and rearing.
   (f) Careful attention to the impact of the farming system on the wider environment and the conservation of wildlife and natural habitats.
3. Importance of Organic Farming are the following :
   (a) Organic faming promotes the use of crop rotations and cover crops, and encourages balanced host/predator relationships.
   (b) Organic residues and nutrients produced on the farm are recycled back to the soil. Cover crops and composted manure are used to maintain soil organic matter and fertility.
   (c) Preventative insect and disease control methods are practiced, including crop rotation, improved genetics and resistant varieties. Integrated pest and weed management, and soil conservation systems are valuable tools on an organic farm.

Practice Questions

Question 1.
What purpose does an electrostatic precipitator serve?
Answer:
It is a device which removes unwanted chemicals from smoke after combustion takes place. The negative charged dust particles are drawn towards positively charged particles collector surface and by knocking the plates particles fall into a hopper tray for disposal.

Question 2.
In the context of reducing air pollutions, give the advantages of changing the process ; maintaining and modifying existing equipment.
Answer:
Change of modify the process of production in order to lower the atmospheric pollutants for example :

1. The coal is washed before crushing it to reduce the fly ash emissions.
2. The process of absorption can be used to remove gaseous air pollutants. In this process, gaseous air pollutants are removed by dissolution into a liquid solvent like water or caustic or acid solution. Absorption is used to remove sulphur dioxide, chlorine, ammonia, nitrogen oxides and hydrocarbons.
3. The process of absorption can be used to remove pollutants from waste water. In this process the target pollutants are made to attach to the surface of activated carbon. This is done by producing carbon through combustion of coal, coconut shells, wood and other organic materials. This carbon is then reacted with steam or carbon dioxide to produce activated carbon. Adsorption helps to remove pollutants as well as bad tastes and odours from drinking water.

Question 3.
What is a scrubber ? With the help of a diagram show its working?
Answer:
It is a device that employs spray of water to catch pollutants

during emissions. In this process, water is introduced into a spray tower by means of a spray nozzle which allow downward flow of water. As the polluted gas flows upwards, the particulates present in the gas collide with the water droplets being sprayed from the spray nozzles. Under the influence of gravitational force, the liquid droplets containing the particulates settle at the bottom.

Question 4.
Describe with the help of a diagram, working of the settling chamber.
Answer:

This device consists of huge rectangular chamber with several . horizontal trays. The gas stream polluted with particulates is allowed to enter from one end. The horizontal velocity of the gas stream is kept low in order to give sufficient time for the particles to settle by gravity. The particulates having high density settle at the bottom of the chamber from where they are removed.

Question 5.
What care should be taken in order to reduce water pollution from non-point sources ?
Answer:
Non-point sources of pollution are the outside sources which affect a large area, e.g. run-off from agricultural fields and deforested areas. Run-off of manure should be diverted to the dry fields, there should be separate drainage for sewage to divert it with rainwater. Natural manure should be used and pest management system should be established for pest control to reduce the use of pesticides.

Question 6.
Briefly state the procedure of treating waste water by primary and secondary treatment. What happens in the tertiary treatment of waste water ?
Answer:
In primary treatment the run-off should be drained through screens, grit chambers and sedimentation tanks to remove toxic chemicals from the water.
In secondary treatment the waste water the primary treatment is brought into contact with sludge heavily laden with micro-organisms. Afterwards the air is passed to give oxygen to the micro-organisms which convert the organic matter into low – energy compounds. The sludge material settles down in the tank and the clean water can be used after treating with chlorine gas.
After primary and secondary treatments, pollutants such as phosphorus and nitrogen are removed, so that the water may be harmless to human health. It is called ‘Advanced Waste Treatment’.

Question 7.
Why is open dumping of solid waste not advisable ? What is done while segregating solid waste ?
Answer:
Open solid waste may pollute directly the air, besides this by washing with rainwater run-off it may pollute a large area and cause soil and water pollution. On the other hand the closed compost system of solid waste may provide good manure. Moisture control is done and micro-organisms help to stabilize the organic matter. First the fungi starts to work and at last actinomycetes break down the waste and convert it to humus known as compost making a good fertilizer.

Question 8.
“Better safe than sorry” is the guiding principle for control of Nuclear pollution. In this context answer the following :

• Explain-the three principles of radiation protection.

Answer:
These are :

1. keeping a distance from source of radiation
2. avoiding length of time of exposure
3. shielding the particular object and human body from the direct radiation.

• What should one do to protect oneself from radiation contamination ?

Answer:
Radioactive particles should not be inhaled by using air filters, using exhaust system is another method, wearing protective clothing prohibiting smoking are essential. Leakage of radioactive elements from nuclear reactors and plants should be checked regularly.

• How should the radioactive waste be stored and disposed of?

Answer:
Ans. Radioactive waste should be stored deep into the ground, where gradual decay may take place. High activity solid wastes could be packed in shielded containers, while low level liquid and gaseous wastes may be diluted before disposal for best possible safety.