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Q1. In a coal-fired power plant, electrostatic precipitators are installed to control the emission of

• NO_x
• SPM
• CO
• SO₂

Solution

Electrostatic precipitators are widely used in power plants to remove 99% of suspended particulate matter (SPM) present in the industrial and thermal power exhausts.

Q2. On a global scale, which country has the highest loss of top soil?

• China
• England
• Italy
• India

Solution

On a global scale, the loss of top soil is maximum (about 18.5%) in India.

Q3. A lake with an inflow of domestic sewage rich in organic waste may result in

• Drying of the lake very soon due to algal bloom
• An increased production of fish due to plenty of nutrients
• Death of fish due to lack of oxygen
• Increased population of aquatic food web organisms

Solution

Phosphorus and nitrates present in domestic sewage act as nutrients and promote the growth of algae which form a cover on the water surface. This process is called eutrophication. The algae use oxygen and deoxygenate the water enough to kill the fish and other animals. The algal cover blocks the entry of light to the submerged plants and slows down photosynthetic activity.

Q4. Atomic weapons use

• Uranium-135
• Uranium-235
• Uranium-165
• Uranium-265

Solution

Atomic weapons use uranium-235 and plutonium-239.

Q5. Photochemical smog is caused by a light-mediated reaction between

• NO₂ and unsaturated hydrocarbons
• NO₂ and O₃
• SO₂ and unburnt hydrocarbons
• SO₂ and O₃

Solution

Photochemical smog is a grey or yellowish brown, opaque smog formed at high temperature over cities and towns due to still air, emission of nitrogen oxides and volatile hydrocarbons from automobile exhausts and solar energy.

Q6. Byssinosis is caused by

• Asbestos
• Stone particles
• Cotton fibres
• Dust particles

Solution

Asbestos causes asbestosis. Stone particles cause silicosis. Cotton fibres cause byssinosis. Dust particles cause lung fibrosis or pneumoconiosis.

Q7. Nutrient enrichment of water bodies causes

• Stratification
• Eutrophication
• Succession
• None of the above

Solution

Phosphorus and nitrates present in domestic sewage act as nutrients and promote the growth of algae which form a cover on the water surface. This process is called eutrophication.

Q8. What is the 3R approach?

• Reduce, Remove and Reuse
• Reuse, Replenish and Remove
• Reduce, Remove and Replenish
• Reduce, Reuse and Recycle

Solution

The 3R approach for the management of wastes includes Reduce, Reuse and Recycle. One can reduce the amount of solid waste at the source itself. One can reuse the materials for some other useful purposes, before recycling or disposing them off. Used and discarded materials like plastic, glass, paper and metal can be sent to the respective industries, where they can be converted into other useful products.

Q9. Which of the following correctly represents the stages in solid waste management?

• Transportation - Collection - Segregation - Dumping
• Segregation - Collection - Transportation - Dumping
• Collection - Segregation - Transportation - Dumping
• Collection - Segregation - Dumping - Transportation

Solution

Solid waste management includes several steps. First is the collection of waste, followed by its proper segregation into wet and dry solid wastes. The wastes are then transported to waste dumping sites, after which they are dumped in landfills for decomposition.

Q10. The term biomagnification refers to the

• Growth of organisms due to food consumption
• Increase in population size
• Blowing up of environmental issues by man
• Increase in the concentration of non-degradable pollutants as they pass through the food chain

Solution

An increase in the concentration of toxic materials at each trophic level of a food chain is called biomagnification or biological magnification.

Q11. Which one of the following is mainly produced by the activity of anaerobic bacteria on sewage?

• Laughing gas
• Propane
• Mustard gas
• Marsh gas

Solution

The activity of anaerobic bacteria on sewage produces biogas, commonly called gobar gas or marsh gas. The major component of biogas is methane. It also includes other gases like carbon dioxide, hydrogen, nitrogen, oxygen and hydrogen sulphide.

Q12. In India, Van Mahotsava is held during

• January and March
• February and July
• October and December
• June and September

Solution

In India, Van Mahotsava is a festival during which plants are planted. It is held in February and July since 1950.

Q13. Thermal pollution results in

• Depletion of O₂
• Increase in the temperature of water bodies
• Death of aquatic animals
• All of the above

Solution

Thermal pollution can have the following effects: 1. Deoxygenation of water and rise in temperature of water. 2. Increase in microbial activity and death of fish. 3. Affects the migration of aquatic animals. 4. Change in composition of flora and fauna in particular zones. 5. Increased toxicity of chemicals in effluents.

Q14. Large-scale disposal of solid waste in low areas of the ground and then covering it with earth is called

• Incineration
• Landfill
• Pyrolysis
• Deep well injection

Solution

Large-scale disposal of solid waste in low areas of the ground and then covering it with earth is called a landfill. Incineration is a method of solid waste destruction in a furnace by controlled burning at high temperatures. Pyrolysis is the decomposition of organic matter at high temperatures in the absence of oxygen. Deep well injection is a liquid waste disposal technology for the disposal of hazardous, industrial and municipal wastewater.

Q15. Strontium-90 accumulates in the

• RBCs
• WBCs
• Bone
• Brain

Solution

Strontium-90 accumulates in the bone and may cause bone cancer.

Q16. The ozone is thickest at the

• Equator
• Poles
• Tropic of Cancer
• Tropic of Capricorn

Solution

The ozone is thickest at the poles and thinnest at the equator.

Q17. Which of the following metals causes harmful effects?

• Lead
• Cobalt
• Uranium
• All of the above

Solution

Radiations from the nuclides of radioactive elements like radium 224, uranium 235, uranium 238, thorium 232, radon 222, potassium 40 and carbon 14 present in the rocks, soil and water cause radioactive pollution. Radioactive lead, cobalt and uranium can bring about adverse effects on human health.

Q18. A common indicator organism of water pollution is

• Eichhornia crassipes
• Escherichia coli
• Entamoeba histolytica
• Lemna paucicostata

Solution

Indicator bacteria are bacteria which are used to detect and estimate the level of faecal contamination in water. Coliform bacteria such as Escherichia coli provide definite evidence of recent faecal pollution.

Q19. Pollution from animal excreta and organic waste from the kitchen can be most profitably minimised by

• Storing them in underground storage tanks
• Using them for producing biogas
• Vermiculture
• Using them directly as biofertilisers

Solution

Biodegradable wastes like animal excreta and organic waste from the kitchen can be used in biogas plants to generate biogas and manure. Biogas is a cheap source of fuel and the manure can be used as a cheap fertiliser.

Q20. Oysters are used for the accumulation of which radioactive material?

• ⁶⁵Zn
• ⁵⁶Zn
• ⁵⁵Fe
• ⁶⁵Fe

Solution

Certain organisms can take up radioactive materials and accumulate them without facing any danger. Oysters can accumulate ⁶⁵Zn.

Q21. Which of the following elements is responsible for Minamata disease?

• Hg
• Pb
• Cd
• Fe

Solution

Minamata disease is caused by methyl mercury poisoning. It was first described in the inhabitants of Minamata Bay, Japan, and resulted due to eating of fish contaminated with mercury (Hg) industrial waste. 

Q22. Allethrin is a

• Fertiliser
• Herbicide
• Growth hormone
• Insecticide

Solution

Allethrins are a group of synthetic compounds used in insecticides. They are synthetic pyrethroids which are found naturally in the Chrysanthemum flower.

Q23. Carbon dioxide is called a greenhouse gas because it is

• Used in a greenhouse to increase plant growth
• Transparent to heat but traps sunlight
• Transparent to sunlight but traps heat
• Transparent to both sunlight and heat

Solution

The greenhouse gases in the atmosphere are transparent to sunlight but can trap heat and keep the Earth’s surface warm. These gases include CO₂, CH₄, CFCs and N₂O. They are called radiatively active gases as they can absorb long wave infrared radiation.

Q24. How should the hazardous waste be disposed of?

• It should be disposed of randomly.
• It should be burnt.
• It should be thrown in the sea.
• It should be disposed of after proper treatment.

Solution

Hazardous waste, if disposed of carelessly, may result in pollution and may even cause serious health problems. Hence, it is necessary to dispose of hazardous wastes after proper treatment, either in sanitary landfills or in incinerators.

Q25. The process of restoring a forest which once existed but was removed at some point of time in the past is called

• Deforestation
• Afforestation
• Reforestation
• Tree plantation

Solution

The process of restoring a forest which once existed but was removed at some point of time in the past is called reforestation. Deforestation is the permanent destruction of forests to make land available for some other purpose. Afforestation is the planting of trees for commercial purposes.

Q26. PCBs are a class of chemicals which cause water pollution. Expand PCBs.

• Polychlorinated biphenyls
• Polychlorinated biphosphates
• Polycarbonated biphenyls
• Polycarbonated biphosphates

Solution

PCBs are polychlorinated biphenyls. 

Q27. The greenhouse effect is due to

• CO₂
• CO
• NO
• PO₄

Solution

The increase in mean global temperature of the Earth due to increased concentration of greenhouse gases like carbon dioxide (CO₂), methane (CH₄), chlorofluorocarbons (CFCs) and nitrous oxide (N₂O) is called the greenhouse effect.

Q28. Which of the following is not a greenhouse gas?

• Carbon dioxide
• Methane
• Ethane
• N₂O

Solution

The greenhouse gases in the atmosphere are transparent to sunlight but can trap heat and keep the Earth’s surface warm. These gases include CO₂, CH₄, CFCs and N₂O. Ethane is not a greenhouse gas.

Q29. Which of the following does not cause desertification?

• Over cultivation
• Restricted grazing
• Deforestation
• Poor irrigation practices

Solution

Desertification is a process which turns productive land into a non-productive desert as a result of poor land management. Some of the causes of desertification are over cultivation, unrestricted grazing, deforestation and poor irrigation practices.

Q30. Which of the following is not a greenhouse gas?

• N₂O
• CFC
• O₃
• SO₂

Solution

The increase in mean global temperature of the Earth due to increased concentration of greenhouse gases like carbon dioxide (CO₂), methane (CH₄), chlorofluorocarbons (CFCs) and nitrous oxide (N₂O) is called the greenhouse effect.

Q31. Checking of reradiating heat by atmospheric dust, O₃, CO₂ and water vapour is called

• Greenhouse effect
• Solar effect
• Ozone layer effect
• Radioactive effect

Solution

The atmospheric cover of the Earth acts like glass walls of a greenhouse. It absorbs most of the incoming solar radiations from the Sun and reradiates them to the Earth’s surface. However, it prevents the long wave infrared radiation emitted by the Earth’s surface to escape into space. In this way, the atmosphere acts as a greenhouse, trapping the heat.

Q32. The Earth Summit was held at

• London, England
• Rio de Janeiro, Brazil
• Kyoto, Japan
• Montreal, Canada

Solution

The Earth Summit was held at Rio de Janeiro, Brazil, in 1992.

Q33. Which of the following accounts for more than 50% of air pollutants?

• Carbon dioxide
• Carbon monoxide
• Smoke
• Oxides of sulphur

Solution

Carbon monoxide accounts for more than 50% of the air pollutants.

Q34. The Chipko movement was launched for the protection of

• Grasslands
• Forests
• Livestock
• Wetlands

Solution

The Chipko Movement was started in 1973 at Gopeshwar town of Chamoli district to check the felling of trees by contractors. The peasant women of Reni village protested by embracing the trees to prevent them from being felled.

Q35. IPCC regularly assesses the concentrations of greenhouse gases and studies its impact on global warming. According to recent surveys, which gas contributes maximum towards the warming effect?

• CH₄
• CO₂
• CFC
• N­₂­O

Solution

According to a recent survey by the IPCC, CO­_2­ contributes to about 60% of the total warming in greenhouse effect.

Q36. The ozone hole causes

• Global warming
• Reduction in the rate of photosynthesis
• More ultraviolet rays coming to the Earth
• Thermal pollution

Solution

Decline in the thickness of the ozone layer over a restricted area is called ozone hole. Depletion in the ozone layer results in more UV radiations reaching the Earth’s surface.

Q37. In radioactivity, beta particles are

• Protons
• Electrons
• Neutrons
• Mesons

Solution

In radioactivity, beta particles are electrons and alpha particles are protons. 

Q38. Which of the following is an effect of waste accumulation?

• Health problems
• Over population
• Urbanisation
• Industrialisation

Solution

Over population, urbanisation and industrialisation are all causes of waste accumulation. Accumulation of solid wastes results in deteriorating living conditions which may cause serious health issues.  

Q39. Greenhouse gases are capable of absorbing

• Short wave infrared radiation
• Long wave infrared radiation
• Short wave radio waves
• Long wave radio waves

Solution

Greenhouse gases are capable of absorbing long wave infrared radiation and hence are also known as radiatively active gases.

Q40. Substances which can be broken down into non-poisonous substances by the action of microorganisms are said to be

• Biodegradable
• Non-biodegradable
• Non-decomposable
• Non-degradable