Q1. A good source of energy should —
(i) release a large amount of heat per unit mass
(ii) be difficult to store
(iii) be very expensive
(iv) produce large amount of smoke
Answer: (i) release a large amount of heat per unit mass

Q2. Which of the following statements is correct regarding fossil fuels?
(i) They are renewable sources of energy
(ii) They were formed over millions of years
(iii) They do not cause air pollution
(iv) They are available in unlimited quantity
Answer: (ii) They were formed over millions of years

Q3. Large number of thermal power plants are set up near coal or oil fields because —
(i) coal and petroleum are renewable
(ii) transmission of electricity is more efficient than transporting coal
(iii) water is not required in thermal plants
(iv) they do not cause pollution
Answer: (ii) transmission of electricity is more efficient than transporting coal

Q4. In a hydro power plant, the electricity is generated by using —
(i) kinetic energy of flowing water directly
(ii) potential energy of water stored at height
(iii) chemical energy of water
(iv) heat energy of water
Answer: (ii) potential energy of water stored at height

Q5. When wood is burnt in a limited supply of oxygen, the residue left behind is —
(i) coal
(ii) coke
(iii) charcoal
(iv) ash
Answer: (iii) charcoal

Q6. In a biogas plant, the gas is produced due to —
(i) decomposition of slurry in presence of oxygen
(ii) decomposition of slurry in absence of oxygen
(iii) burning of cow-dung
(iv) heating of slurry at high temperature
Answer: (ii) decomposition of slurry in absence of oxygen

Q7. Assertion (A): Wind energy is an environment-friendly source of energy.
Reason (R): Wind energy requires no recurring expenses for production of electricity.
(i) Both A and R are true and R is the correct explanation of A
(ii) Both A and R are true but R is not the correct explanation of A
(iii) A is true but R is false
(iv) A is false but R is true
Answer: (ii) Both A and R are true but R is not the correct explanation of A

Q8. Which of the following conditions is necessary for setting up a wind energy farm?
(i) Wind speed should be less than 5 km/h
(ii) Wind speed should be higher than 15 km/h
(iii) It can be set up anywhere
(iv) Small area of land is sufficient
Answer: (ii) Wind speed should be higher than 15 km/h

Q9. Match the following:

Column A | Column B
(a) Bio-gas | (1) Falling water
(b) Hydro power | (2) Methane
(c) Solar cell | (3) Silicon
(d) Windmill | (4) Rotatory motion

(i) a–2, b–1, c–3, d–4
(ii) a–1, b–2, c–4, d–3
(iii) a–3, b–4, c–2, d–1
(iv) a–4, b–3, c–1, d–2
Answer: (i) a–2, b–1, c–3, d–4

Q10. When a black and a white painted flask filled with water are kept in sunlight for one hour, the water in the black flask becomes hotter because —
(i) black surface reflects more heat
(ii) white surface absorbs more heat
(iii) black surface absorbs more heat
(iv) black surface produces heat
Answer: (iii) black surface absorbs more heat

Q11. Which gas is produced in large amount during decomposition of slurry in a biogas plant?
(i) Oxygen
(ii) Nitrogen
(iii) Methane
(iv) Hydrogen chloride
Answer: (iii) Methane

Q12. The main component of bio-gas which makes it an excellent fuel is —
(i) Carbon dioxide
(ii) Methane
(iii) Hydrogen sulphide
(iv) Nitrogen
Answer: (ii) Methane

Q13. A typical solar cell develops a voltage of about —
(i) 0.05–0.1 V
(ii) 0.5–1 V
(iii) 5–10 V
(iv) 50–100 V
Answer: (ii) 0.5–1 V

Q14. A large number of solar cells combined together form a —
(i) Solar cooker
(ii) Solar heater
(iii) Solar panel
(iv) Solar reflector
Answer: (iii) Solar panel

Q15. The energy obtained from the difference in temperature between the surface water and deep water of the ocean is called —
(i) Tidal energy
(ii) Wave energy
(iii) Ocean thermal energy
(iv) Geothermal energy
Answer: (iii) Ocean thermal energy

Q16. Tidal energy is harnessed by —
(i) constructing a dam across a narrow opening to the sea
(ii) using mirrors to focus sunlight
(iii) drilling deep wells in the earth
(iv) burning fossil fuels
Answer: (i) constructing a dam across a narrow opening to the sea

Q17. Assertion (A): Geothermal energy can be obtained from hot spots inside the earth’s crust.
Reason (R): Steam produced in hot spots can be used to rotate a turbine.
(i) Both A and R are true and R is the correct explanation of A
(ii) Both A and R are true but R is not the correct explanation of A
(iii) A is true but R is false
(iv) A is false but R is true
Answer: (i) Both A and R are true and R is the correct explanation of A

Q18. In a nuclear reactor, energy is produced by —
(i) chemical reaction
(ii) nuclear fusion
(iii) nuclear fission
(iv) combustion
Answer: (iii) nuclear fission

Q19. Which of the following is a major hazard of nuclear power generation?
(i) Production of smoke
(ii) Storage and disposal of radioactive waste
(iii) Low heat generation
(iv) Requirement of large wind speed
Answer: (ii) Storage and disposal of radioactive waste

Q20. Match the following:

Column A | Column B
(a) Thermal power plant | (1) Burning of fossil fuels
(b) Hydro power plant | (2) Flowing water at height
(c) Wind energy | (3) Unequal heating of land and water
(d) Geothermal energy | (4) Hot spots inside earth

(i) a–1, b–2, c–3, d–4
(ii) a–2, b–1, c–4, d–3
(iii) a–3, b–4, c–1, d–2
(iv) a–4, b–3, c–2, d–1
Answer: (i) a–1, b–2, c–3, d–4

Q21. The phenomenon of rise and fall of sea level due to the gravitational pull of the moon is called —
(i) Ocean current
(ii) Tides
(iii) Waves
(iv) Ocean thermal difference
Answer: (ii) Tides

Q22. Ocean thermal energy conversion plants can operate when the temperature difference between surface water and deep water is at least —
(i) 5 K
(ii) 10 K
(iii) 20 K
(iv) 50 K
Answer: (iii) 20 K

Q23. The ultimate source of energy for wind energy is —
(i) Moon
(ii) Sun
(iii) Earth’s core
(iv) Nuclear reactor
Answer: (ii) Sun

Q24. In the activity demonstrating generation of electricity using steam, the steam rotates —
(i) generator directly
(ii) turbine blades
(iii) bulb filament
(iv) battery
Answer: (ii) turbine blades

Q25. Which of the following is an exhaustible source of energy?
(i) Wind energy
(ii) Solar energy
(iii) Fossil fuels
(iv) Tidal energy
Answer: (iii) Fossil fuels

Q26. Assertion (A): Solar cells are useful in remote and inaccessible areas.
Reason (R): Laying power transmission lines to such areas may be expensive and not commercially viable.
(i) Both A and R are true and R is the correct explanation of A
(ii) Both A and R are true but R is not the correct explanation of A
(iii) A is true but R is false
(iv) A is false but R is true
Answer: (i) Both A and R are true and R is the correct explanation of A

Q27. Which of the following is not ultimately derived from solar energy?
(i) Biomass
(ii) Wind energy
(iii) Geothermal energy
(iv) Fossil fuels
Answer: (iii) Geothermal energy

Q28. The slurry left behind in a biogas plant is used as —
(i) fuel
(ii) fertiliser rich in nitrogen and phosphorous
(iii) coolant
(iv) lubricant
Answer: (ii) fertiliser rich in nitrogen and phosphorous

Q29. Match the following:

Column A | Column B
(a) Solar cooker | (1) Greenhouse effect
(b) Wind energy farm | (2) Large area of land
(c) Nuclear fission | (3) Heavy nucleus splitting
(d) Charcoal | (4) Limited supply of oxygen

(i) a–1, b–2, c–3, d–4
(ii) a–2, b–1, c–4, d–3
(iii) a–3, b–4, c–1, d–2
(iv) a–4, b–3, c–2, d–1
Answer: (i) a–1, b–2, c–3, d–4

Q30. The major gases responsible for acid rain formed due to burning of fossil fuels are —
(i) Oxides of carbon, nitrogen and sulphur
(ii) Oxygen and nitrogen
(iii) Hydrogen and helium
(iv) Methane and ammonia
Answer: (i) Oxides of carbon, nitrogen and sulphur

Q31. Which of the following statements about hydro power is correct?
(i) It is a non-renewable source of energy
(ii) It depends on the rainfall for refilling reservoirs
(iii) It produces large amount of smoke
(iv) It does not require dams
Answer: (ii) It depends on the rainfall for refilling reservoirs

Q32. One disadvantage of constructing large dams is —
(i) production of oxygen
(ii) submergence of agricultural land and human habitation
(iii) unlimited electricity generation
(iv) no environmental impact
Answer: (ii) submergence of agricultural land and human habitation

Q33. When vegetation submerged under water in dams rots under anaerobic conditions, it produces large amounts of —
(i) Oxygen
(ii) Nitrogen
(iii) Methane
(iv) Hydrogen
Answer: (iii) Methane

Q34. In a nuclear fission reaction, the energy released is due to —
(i) increase in mass
(ii) decrease in mass converted into energy
(iii) chemical reaction
(iv) combustion of fuel
Answer: (ii) decrease in mass converted into energy

Q35. Which of the following requires wind speed higher than 15 km/h for effective operation?
(i) Solar cell
(ii) Wind energy farm
(iii) Biogas plant
(iv) Nuclear reactor
Answer: (ii) Wind energy farm

Q36. Assertion (A): Charcoal is a better fuel than wood.
Reason (R): Charcoal burns without flame and has higher heat generation efficiency.
(i) Both A and R are true and R is the correct explanation of A
(ii) Both A and R are true but R is not the correct explanation of A
(iii) A is true but R is false
(iv) A is false but R is true
Answer: (i) Both A and R are true and R is the correct explanation of A

Q37. Which of the following is an advantage of solar cells?
(i) They have moving parts
(ii) They require frequent maintenance
(iii) They can be used in remote areas
(iv) They are very cheap to manufacture
Answer: (iii) They can be used in remote areas

Q38. The process in which a heavy nucleus splits into lighter nuclei on bombardment with neutrons is called —
(i) Nuclear fusion
(ii) Nuclear fission
(iii) Combustion
(iv) Oxidation
Answer: (ii) Nuclear fission

Q39. Match the following:

Column A | Column B
(a) Tidal energy | (1) Gravitational pull of moon
(b) Ocean thermal energy | (2) Temperature difference in sea
(c) Geothermal energy | (3) Hot springs
(d) Wind energy | (4) Unequal heating of land and water

(i) a–1, b–2, c–3, d–4
(ii) a–2, b–1, c–4, d–3
(iii) a–3, b–4, c–1, d–2
(iv) a–4, b–3, c–2, d–1
Answer: (i) a–1, b–2, c–3, d–4

Q40. Renewable sources of energy are those which —
(i) get depleted after some time
(ii) cannot be regenerated
(iii) can be regenerated and replenished
(iv) are formed over millions of years
Answer: (iii) can be regenerated and replenished