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1

The efficiency of a modern natural gas power station is approximately A. 10%.

B. 50%.

C. 75%.

D. 90%

B. 50 %

2

The energy source that currently provides the greatest proportion of the world’s total energy demand is

A. coal.

B. oil.

C. natural gas.

D. uranium.

B. oil. 

3

In a nuclear power station, uranium is used as the energy source and plutonium-239 is produced. Which of the following is true?

A. Plutonium-239 is produced by nuclear fusion.

B. A moderator is used to absorb plutonium-239.

C. Control rods are used to slow down plutonium-239.

D. Plutonium-239 can be used as a fuel in another type of nuclear reactor.

D. Plutonium-239 can be used as a fuel in another type of nuclear reactor.

4

One disadvantage of using photovoltaic cells to power a domestic water heater is that

A. solar energy is a renewable source of energy.

B. the power radiated by the Sun varies significantly depending on the weather.

C. a large area of photovoltaic cells would be needed.

D. photovoltaic cells contain CFCs, which contribute to the greenhouse effect

C. a large area of photovoltaic cells would be needed. 

5

Greenhouse gases

A. reflect infrared radiation but absorb ultraviolet radiation.

B. reflect ultraviolet radiation but absorb infrared radiation.

C. transmit infrared radiation but absorb ultraviolet radiation.

D. transmit ultraviolet radiation but absorb infrared radiation

D. transmit ultraviolet radiation but absorb infrared radiation

6

The rate of global warming might be reduced by

A. replacing the use of coal and oil with natural gas.

B. a reduction in the Earth’s albedo.

C. a reduction in carbon fixation.

D. an increase in deforestation.

A. replacing the use of coal and oil with natural gas. 

7

The unit of energy density of a fuel is

A. Jm–2.

B. Jm–3.

C. J kg–1.

D. kgJ –1

C. J kg–1. 

8

Which of the following is the best estimate for the overall efficiency of a typical coal power station?

A. 5%

B. 30%

C. 60%

D. 90%

B. 30%

9

When sunlight is incident on a solar cell an electric current is produced. This is due to

A. a temperature gradient within the cell.

B. very long wavelength infrared radiation.

C. very short ultraviolet radiation.

D. the photoelectric effect.

D. the photoelectric effect.

10

The power per unit length P of an oscillating water column (OWC)is due to the action of a surface wave of amplitude A. Which of the following correctly relates P and A, and correctly identifies the nature of the energy of the water column?

           Relation between P and A                      Nature of energy

A.                  P∝ A                                                      kinetic

B.                 P∝ A                                             kinetic and potential

C.                 P∝ A2                                                     kinetic

D.                 P∝ A2                                          kinetic and potential

D. relation between P and A isP∝ A2  and the nature of energy is      kinetic and potential

11

The average temperature of the surface of the Sun is about 20 times more than the average surface temperature of the Earth. The average power per unit area radiated by the Earth is P. The average power per unit area radiated by the Sun is

A. 20P.

B. 400P.

C. 8000P.

D. 160000P.

D. 160000P.

12

Global warming reduces the ice and snow cover on Earth. Which of the following correctly describes the changes in albedo and rate of energy absorption by Earth?

                          Albedo                         Rate of energy absorption

A.                   increase                                        increase

B.                      decrease                                    increase

C.                    increase                                       decrease

D.                   decrease                                       decrease

B. the albedo decreases and the rate of energy absorption increases

13

Which of the following energy sources results from the solar energy incident on Earth?

A. Nuclear fission

B. Wind energy

C. Nuclear fusion

D. Geothermal energy

B. Wind energy 

14

Which of the following is a renewable and non-renewable energy source?

                         Renewable                                 Non-renewable

A.                       uranium                                            coal

B.                          tidal                                            uranium

C.                         uranium                                         biogas

D.                         natural gas                                    biogas

B. tidal is renewable and uranium is non-renewable

15

A thermal power station is 20% efficient and generates useful electrical power at 1000MW. The fossil fuel used has an energy density of 50MJkg–1. The mass of fuel in kg consumed every second is given by which of the following?

A. 0.01

B. 0.25

C. 4

D. 100

D. 100

16

Which of the following is likely to increase greenhouse gas concentrations in the atmosphere?

A. Using natural gas instead of coal to generate electrical energy

B. Incineration of waste to generate electrical energy

C. Increased use of wind turbines to generate electrical energy

D. Carbon dioxide capture and storage at the power station

B. Incineration of waste to generate electrical energy 

17

Venus and Earth may be regarded as behaving as black bodies. The mean temperature at the surface of Venus is about 600K and at the surface of Earth is about 300K. Which of the following is the best estimate for the ratio

power radiated per unit area on Earth/power radiated per unit area on Venus ?

A. 1/2 .

B. 1/4 .

C. 1/8 .

D. 1/16 .

D. 1/16

18

In a nuclear power station, a moderator is required to

A. control the rate of fission.

B. reduce heat losses to the surroundings.

C. reduce the energy of high energy neutrons.

D. increase the energy of low energy neutrons.

C. reduce the energy of high energy neutrons. 

19

Degraded energy is energy that is

A. stored in the Earth’s atmosphere.

B. available from non-renewable energy sources.

C. converted into work in a cyclical process.

D. no longer available for the performance of useful work.

D. no longer available for the performance of useful work.

20

Which of the following correctly describes both the role of the moderator and of the control rods in a nuclear reactor?

                 Moderator                                         Control rods

A.       slows down the neutrons      maintain a constant rate of fission

B.      cools down the reactor                extract thermal energy

C.      cools down the reactor       maintain a constant rate of fission

D.        slows down the neutrons         extract thermal energy

A. the moderator slows down the neutrons and control rods maintain a constant rate of fission

21

Which of the following correctly shows the energy change in a photovoltaic cell and in a solar heating panel?

           Photovoltaic cell                         Solar heating panel

A.          solar → electrical                       solar → thermal

B.            electrical → thermal                 solar → electrical

C.             solar → electrical                   electrical → thermal

D.         electrical → thermal                     solar → thermal

A. in a photovoltaic cell the solar energy is converted into electrical energy and in a solar heating panel the solar energy is converted into thermal energy

22

The albedo for the oceans is lower than that for glaciers. This is because, compared to ice, sea water

A. has a greater density.

B. has a greater specific heat capacity.

C. has a greater coefficient of volume expansion.

D. absorbs a greater amount of radiative power

D. absorbs a greater amount of radiative power

23

Which of the following is most likely to reduce the enhanced greenhouse effect?

A. Replace the use of gas powered stations with oil powered stations

B. Replace coal-fired power stations with nuclear power stations

C. Increase the use of all non-renewable energy sources

D. Decrease the efficiency of power production

B. Replace coal-fired power stations with nuclear power stations 

24

Which of the following correctly shows a renewable and a non-renewable source of energy?

           Renewable                              Non-renewable

A.             oil                                          geothermal

B.           wind                                          biofuels

C.           ocean waves                            nuclear

D.           natural gas                                  coal

C. ocean waves are renewable and nuclear is nonrenewable

25

Critical mass refers to the amount of fissile material that

A. will allow fission to be sustained.

B. is equivalent to 235 g of uranium.

C. will produce a growing chain reaction.

D. is the minimum mass necessary for fission to take place.

A. will allow fission to be sustained. 

26

The annual variations of solar power incident per unit area at a particular point on the Earth’s surface is mainly due to the change in the

A. distance between the Earth and the Sun.

B. angle at which the solar rays hit the surface of the Earth.

C. average albedo of the Earth.

D. average cloud cover of the Earth. 

B. angle at which the solar rays hit the surface of the Earth. 

27

The water in a reservoir behind a dam drops from an initial height H0 above a turbine to produce hydroelectricity. At time t =T, h =0.

 The graph shows the variation with time t of the height h of the water above the turbine.

Which of the following is a measure of the maximum theoretical electric power available?

A. H0 and the slope of the graph

B. T and the slope of the graph

C. T and the area under the graph

D. H0 and the area under the graph

A. H0 and the slope of the graph 

28

Each square metre of the Sun’s surface emits S joules per second. The radius of the Sun is r, and the Sun is at a mean distance R from the Earth. Which of the following gives the solar power incident per unit area of the top layer of the Earth’s atmosphere? 

A. (r/R)S

B. (r/R)2S

C. (R/r)S

D. (R/r)2S

B. (r/R)2S

29

The diagram shows a simple climate model for Earth. The temperature of the ground is Tg and is assumed to radiate as a black body. The temperature of the atmosphere is Ta and has an emissivity ε.

In the model, the intensity radiated from the ground equals the intensity radiated from the atmosphere towards the ground. What is the ratio Tg/Ta ?

A. ε4

B. ε

C. ε1/4

D. 1

C. ε1/4

30

A wave generator produces a power per unit length of 4.0kWm–1 for waves of amplitude A and speed v. The efficiency of the generator is constant. The power per unit length obtained from waves of amplitude 2A and speed 2v would be

A. 8.0 kWm–1.

B. 16kWm–1.

C. 32kWm–1.

D. 64kWm–1.

C. 32kWm–1