Power_Climate_P1 [65 marks]

1. What is equivalent to

?

A. density of the fuel

B.

C.

D.

specific energy of a fuelenergy density of a fuel

1density of the fuel

energy stored in the fueldensity of the fuel

density of the fuelenergy stored in the fuel

2. Three energy sources for power stations are

I. fossil fuel

II. pumped water storage

III. nuclear fuel.

Which energy sources are primary sources?

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

The diagram shows a simple climate model for the Earth.

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3. The diagram shows a simple climate model for the Earth.

What does this model predict for the average albedo of the Earth?

A. 0.30

B. 0.51

C. 0.70

D. 0.81

4. A wind turbine has a power output p when the wind speed is v. The efficiency of thewind turbine does not change. What is the wind speed at which the power output is ?

A.

B.

C.

D.

p

2v4v

√8

v2v

3√2

5. Three gases in the atmosphere are

I. carbon dioxide (CO )

II. dinitrogen monoxide (N O)

III. oxygen (O ).

Which of these are considered to be greenhouse gases?

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

2

2

2

power radiated by Mars

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6. Mars and Earth act as black bodies. The and

.

What is the value of ?

A.

B.

C.

D.

= ppower radiated by Mars

power radiated by the Earth

= tabsolute mean temperature of the surface of Mars

absolute mean temperature of the surface of the Earth

radius of Marsradius of the Earth

p

t4

√p

t2

t4

p

t2

√p

7. A nuclear reactor contains atoms that are used for moderation and atoms that are usedfor control.

What are the ideal properties of the moderator atoms and the control atoms in terms of neutronabsorption?

8. The dashed line on the graph shows the variation with wavelength of the intensity ofsolar radiation before passing through the Earth’s atmosphere.

The solid line on the graph shows the variation with wavelength of the intensity of solar radiationafter it has passed through the Earth’s atmosphere.

Which feature of the graph helps explain the greenhouse effect?

A. Infrared radiation is absorbed at specific wavelengths.

B. There is little absorption at infrared wavelengths.

C. There is substantial absorption at visible wavelengths.

D. There is little absorption at UV wavelengths.

The Sankey diagram shows the energy input from fuel that is eventually converted to

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9. The Sankey diagram shows the energy input from fuel that is eventually converted touseful domestic energy in the form of light in a filament lamp.

What is true for this Sankey diagram?

A. The overall efficiency of the process is 10%.

B. Generation and transmission losses account for 55% of the energy input.

C. Useful energy accounts for half of the transmission losses.

D. The energy loss in the power station equals the energy that leaves it.

10. What part of a nuclear power station is principally responsible for increasing the chancethat a neutron will cause fission?

A. Moderator

B. Control rod

C. Pressure vessel

D. Heat exchanger

11. Which of the energy sources are classified as renewable and non-renewable?

12. The energy density of a substance can be calculated by multiplying its specific energywith which quantity?

A. mass

B. volume

C.

D.

massvolume

volumemass

A black body emits radiation with its greatest intensity at a wavelength of I . The

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13. A black body emits radiation with its greatest intensity at a wavelength of I . Thesurface temperature of the black body doubles without any other change occurring.What is the wavelength at which the greatest intensity of radiation is emitted?

A. I

B.

C.

D.

max

max

Imax

2

Imax

4

Imax

16

14. The three statements give possible reasons why an average value should be used forthe solar constant.

I. The Sun’s output varies during its 11 year cycle.II. The Earth is in elliptical orbit around the Sun.III. The plane of the Earth’s spin on its axis is tilted to the plane of its orbit about the Sun.

Which are the correct reasons for using an average value for the solar constant?

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

15. The following are energy sources.

I. a battery of rechargeable electric cellsII. crude oilIII. a pumped storage hydroelectric system

Which of these are secondary energy sources?

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

Planet X and planet Y both emit radiation as black bodies. Planet X has a surface

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16. Planet X and planet Y both emit radiation as black bodies. Planet X has a surfacetemperature that is less than the surface temperature of planet Y.

What is the graph of the variation of intensity I with wavelength λ for the radiation emitted byplanet Y? The graph for planet X is shown dotted.

17. The average surface temperature of Mars is approximately 200 K and the averagesurface temperature of Earth is approximately 300 K. Mars has a radius half that ofEarth. Assume that both Mars and Earth act as black bodies.

What is ?

A. 20B. 5C. 0.2D. 0.05

power radiated by Marspower radiated by Earth

18. The main role of a moderator in a nuclear fission reactor is to

A. slow down neutrons.

B. absorb neutrons.

C. reflect neutrons back to the reactor.

D. accelerate neutrons.

19. A room is at a constant temperature of 300 K. A hotplate in the room is at a temperatureof 400 K and loses energy by radiation at a rate of P. What is the rate of loss of energyfrom the hotplate when its temperature is 500 K?

A. P

B. P

C. P

D. P

44

54

54+34

44+34

54

44

54−34

44−34

An object can lose energy through

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20. An object can lose energy through

I. conductionII. convectionIII. radiation

What are the principal means for losing energy for a hot rock resting on the surface of theMoon?

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

21. The average albedo of glacier ice is 0.25.

What is ?

A. 0.25

B. 0.33

C. 2.5

D. 3.0

power absorbed by glacier icepower reflected by glacier ice

22. The Sankey diagram represents the energy flow for a coal-fired power station.

What is the overall efficiency of the power station?

A. 0.3

B. 0.4

C. 0.6

D. 0.7

23. Which of the following is not a primary energy source?

A. Wind turbine

B. Jet Engine

C. Coal-fired power station

D. Nuclear power station

What are the principal energy changes in a photovoltaic cell and in a solar heating

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24. What are the principal energy changes in a photovoltaic cell and in a solar heatingpanel?

25. The solar constant is the intensity of the Sun’s radiation at

A. the surface of the Earth. B. the mean distance from the Sun of the Earth’s orbit around the Sun. C. the surface of the Sun. D. 10km above the surface of the Earth.

26. X and Y are two spherical black-body radiators that emit the same total power. Theabsolute temperature of X is half that of Y.

What is ?

A. 4

B. 8

C. 16

D. 32

radius of Xradius of Y

27. A solar panel has surface area 0.40m and efficiency 50%. The average intensity ofradiation reaching the surface of the panel is 0.25kWm . What is the average poweroutput from an array of 10 of these solar panels?

A. 0.5 W

B. 5 W

C. 50 W

D. 500 W

2

–2

28. What is the correct order of energy transformations in a coal power station?

A. thermal → chemical → kinetic → electrical

B. chemical → thermal → kinetic → electrical

C. chemical → kinetic → thermal → electrical

D. kinetic → chemical → electrical → thermal

A black body of surface 1.0m emits electromagnetic radiation of peak wavelength2

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29. A black body of surface 1.0m emits electromagnetic radiation of peak wavelength2.90×10 m. Which of the following statements about the body are correct?

I. The temperature of the body is 1000 K.II. The energy radiated by the body in one second is 5.7×10 J.III. The body is a perfect absorber of electromagnetic radiation.

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

2

–6

4

30. It is suggested that the solar power incident at a point on the Earth’s surface dependson

I. daily variations in the Sun’s power output

II. the location of the point

III. the cloud cover at the point.

Which suggestion(s) is/are correct?

A. III only

B. I and II only

C. II and III only

D. I, II and III

31. In nuclear power production, what is one advantage of a nuclear fusion reactor over anuclear fission reactor?

A. The operating temperature of the fusion reactor is lower.

B. The nuclear reactants are more easily confined within the core of the fusion reactor.

C. The disposal of the nuclear waste products from the fusion reactor is more straightforward.

D. The nuclear fusion reaction is more easily sustained for long periods of time.

32. Which type of power-production system is most suitable for responding to a suddenhigh increase in demand for electrical power?

A. A wind generator

B. A tidal water storage hydroelectric scheme

C. An ocean-wave energy converter

D. A pump storage hydroelectric scheme

33. Methane and carbon dioxide are both greenhouse gases that are believed to causeglobal warming. The reason for this is that these gases

A. absorb incoming radiation from the Sun.

B. transmit the incoming radiation from the Sun and radiation from the Earth.

C. reflect incoming radiation from the Sun.

D. transmit incoming radiation from the Sun and absorb outgoing radiation from the Earth.

An electric motor is used to lift a heavy load. The Sankey diagram shows the energy

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34. An electric motor is used to lift a heavy load. The Sankey diagram shows the energytransformations involved in the process.

What is the efficiency of the motor?

A. 33%

B. 50%

C. 67%

D. 75%

The graph shows the emission spectrum for a black body at absolute temperature T .

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35. The graph shows the emission spectrum for a black body at absolute temperature T .

Which graph shows the emission spectrum for the same black body at an absolutetemperature T where T > T ? The original graph is shown as a dotted line.

1

2 2 1

Changes in the climate are leading to a reduction in ice cover on Earth. Which of the

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36. Changes in the climate are leading to a reduction in ice cover on Earth. Which of thefollowing describes, for Earth, the change in albedo and the change in the rate ofenergy absorption?

37. A natural gas power station has an output of 600 MW and an efficiency of 50%. Themass of natural gas that is burned per second is 20kg. What is the energy density ofnatural gas?

A. 15 MJkgB. 30 MJkgC. 40 MJkgD. 60 MJkg

–1

–1

–1

–1

38. A black body has kelvin temperature T and surface area A. The total power radiated bythe body is P. What is the new power radiated when T is doubled and A is halved?

A. 4PB. 8PC. 16PD. 32P

The average intensity of the solar radiation incident on a planet is 200 W m . The–2

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39. The average intensity of the solar radiation incident on a planet is 200 W m . Thealbedo of the planet is 0.6. The average temperature of the planet is constant.

Which of the following is a correct statement about the intensity of radiation reflected andradiated by the planet?

–2

40. A uranium nuclear fission reactor that attempts to operate without a moderator would

A. suffer core meltdown.B. not require uranium enrichment.C. produce too much energy.D. produce very little energy.

41. In the production of energy from nuclear fission, fuel enrichment means increasing, inthe fuel rods, the amount of

A. uranium-238.

B. plutonium-239.

C. uranium-235.

D. uranium-235 and plutonium-239.

42. In a wind generator, the kinetic energy of the wind cannot be completely converted intomechanical kinetic energy. This is because

A. momentum is not conserved in the collisions between air molecules and the blades.

B. the density of the air depends on the temperature of the air.

C. the air molecules cannot be brought completely to rest in collisions with the blades.

D. the wind speed does not remain constant.

43. The greenhouse effect can be explained by the fact that the infrared radiation emittedby the surface of Earth

A. is absorbed by the atmosphere and then re-radiated in all directions.

B. raises the temperature of the upper atmosphere.

C. is trapped by the upper atmosphere.

D. is absorbed by the atmosphere and then all of it is re-radiated back to the surface of Earth.

A body X of emissivity e is at temperature T . X is inside a box whose walls act as a

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44. A body X of emissivity e is at temperature T . X is inside a box whose walls act as ablack body of temperature T . T is greater than T .

What is the net intensity of radiation leaving body X?

A.

B.

C.

D.

1

2 1 2

σT14

eσT14

eσT14 − σT2

4

eσ (T14 − T2

4)

45. In a hydroelectric power plant, water of density 10 kgm falls through an averageheight of 100m. The volume of water flowing through the pipes per second is 10m s .What is the maximum power generated?

A. 10 W

B. 10 W

C. 10 W

D. 10 W

3 –3

3 –1

4

5

6

7

46. A black body has absolute temperature T and surface area A. The intensity of theradiation emitted by the body is I. Another black body of surface area 2 A has absolutetemperature 2T. What is the intensity of radiation emitted by this second black body?

A. 4I

B. 8I

C. 16I

D. 32I

In the production of electric power, an advantage of using photovoltaic cells rather than

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47. In the production of electric power, an advantage of using photovoltaic cells rather thanfossil fuels is that the photovoltaic cells

A. can be effective in any location.B. can be used continuously.C. have low initial set-up costs.D. are more environmentally friendly when in use.

48. What is the main role of the control rods and the main role of the moderator in a thermalfission reactor?

49. The surface temperature of a black-body emitter is doubled. By what factor does thepower emitted by the body increase?

A. 32B. 16C. 4D. 2

50. Which option is not a possible solution to reduce the enhanced greenhouse effect?

A. Decommission nuclear power plantsB. Replace the use of coal and oil with natural gasC. Use combined heating and power (CHP) systemsD. Use hybrid motor vehicles

51. The use of which energy source enhances the greenhouse effect the most?

A. WoodB. CoalC. WindD. Tidal

A student states that the following factors may lead to global warming

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52. A student states that the following factors may lead to global warming

I. decreased albedo of the Earth’s surfaceII. increase in volcanic activityIII. deforestation.

Which of the above statements are correct?

A. I and II onlyB. II and III onlyC. I and III onlyD. I, II and III

53. Increasing the temperature of a black-body will have the following effect on its emissionspectrum.

54. The blades of a certain wind turbine X have radius r. The maximum theoreticalavailable wind power for a given wind speed is P. Another similar turbine Y has bladesof radius 2r. What is the best estimate for the maximum theoretical available wind power fromturbine Y?

A. 8P

B. 4P

C.

D.

P4

P8

55. The property of the molecules of greenhouse gases which leads to their ability to absorbinfrared radiation is their

A. resonant frequency.B. speed of rotation.C. total electric charge.D. diameter.

56. Which of the following geographical features has the lowest albedo?

A. Polar ice capB. DesertC. OceanD. White cliffs

Which of the following alternatives would be the most likely to increase the enhanced

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57. Which of the following alternatives would be the most likely to increase the enhancedgreenhouse effect?

A. Replacement of oil and coal fired power stations with natural gas fired power stationsB. Forests being cut down without being replantedC. Greater use of combined heating and power systemsD. Use of motor vehicles powered by a combination of electricity and oil products

58. What is the phenomenon that best explains why greenhouse gases absorb infraredradiation?

A. ResonanceB. InterferenceC. RefractionD. Diffraction

59. The design of a nuclear power station includes an electrical generator. The function ofthe generator is to convert

A. nuclear energy to kinetic energy.B. kinetic energy to thermal energy.C. thermal energy to electrical energy.D. kinetic energy to electrical energy.

60. Which of the following processes leads to the production of a nucleus of plutonium-239from a nucleus of uranium-238?

1. Neutron capture by uranium nucleus

2. Radioactive decay of uranium nucleus

3. Electron capture by uranium nucleus

4. Nuclear ssion of uranium nucleus

61. Large areas of rainforests are cut down and burned every year. The result of theseactions is

1. reduced albedo.

2. reduced carbon fixation.

3. increased evaporation rate.

4. increased mass of atmospheric methane.

62. Which of the following describes the role of the atmosphere in the greenhouse effect?

1. The atmosphere is transparent to all solar radiation.

2. The atmosphere absorbs infrared radiation from the ground.

3. The atmosphere scatters red light more than blue light.

4. Clouds in the atmosphere prevent absorption of infrared radiation.

The diagram shows the variation with wavelength of the power per unit wavelength

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Printed for HAEF (Psychico College)

© International Baccalaureate Organization 2019 International Baccalaureate® - Baccalauréat International® - Bachillerato Internacional®

63. The diagram shows the variation with wavelength of the power per unit wavelength radiated from an area of of two different bodies.

Which of the following is a correct comparison of the temperature and of the emissivity of thetwo bodies?

I1 m2

64. The diagram shows an energy balance climate model for a planet.

The intensities of the reflected and radiated radiation are given in terms of the incident intensity . Which of the following is the albedo of this planet?

A. 0.15

B. 0.25

C. 0.40

D. 0.60

I

65. Venus and Earth may be regarded as behaving as black bodies. The meantemperature at the surface of Venus is about 600 K and at the surface of Earth is about300 K. Which of the following is the best estimate for the ratio ?

A.

B.

C.

D.

power radiated per unit area on Earthpower radiated per unit area on Venus

12

14

18

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