Question 21 : The increase in the concentration of CO2 in our environment in last fifty years; since 1960 is about
1. 20%
2. 10%
3. 14%
4. 6%
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Question 22 : How the biological oxygen demand gets affected with the increased presence of organic matter in water?
1. the oxygen demand increases
2. the oxygen demand decreases
3. the oxygen demand remains unchanged
4. none of the mentioned
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Question 23 : Fuel cell performance is not limited by
1. First law of Thermodynamics
2. Second law of Thermodynamics
3. Third law of Thermodynamics
4. All three laws are applicable
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Question 24 : The fuel cell is considered a battery in which ___ is continuously replaced.
1. fuel only
2. oxidizer
3. both fuel and oxidizer
4. none of the mentioned
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Question 25 : Which of the following is a disadvantage of most of the renewable energy sources?
1. Highly polluting
2. High waste disposal cost
3. Unreliable supply
4. High running cost
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Question 26 : The most serious environmental effect posed by hazardous wastes is
1. air pollution
2. contamination of groundwater
3. increased use of land for landfills
4. destruction of habitat
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Question 27 : The three primary soil macronutrients are
1. carbon, oxygen and water
2. copper, cadmium and carbon
3. potassium, phosphorus and nitrogen
4. boron, zinc and manganese
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Question 28 : Horizontal axis and vertical axis are the types of:
1. Nuclear reactor
2. Wind mills
3. Biogas reactor
4. Solar cell
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Question 29 : What is the harm from the depletion of Earth's ozone layer?
1. The average temperature of earth's surface will increase gradually
2. The oxygen content of the atmosphere will decrease
3. Increased amount of Ultra violet radiation will reach earth's surface
4. Sea levels will rise as the polar ice caps will gradually melt
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Question 30 : Fuel cells are:
1. Carbon cell
2. Hydrogen battery
3. Nuclear cell
4. Chromium cell
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