Target: 10 Questions in 10 minutes

An IB Physics data booklet is helpful

1. What is the value of the emissivity of an ideal black surface and an ideal silver (mirrored) surface?

black surface silver surface
A
 0 1
B
 1 0
C
 infinite 0
D
 0 infinite

2. Which of the following is the best definition of the 'albedo' of a body?

  • A. The fraction of radiation scattered compared to the incident radiation.
  • B. The fraction of radiation absorbed compared to the incident radiation.
  • C. The fraction of radiation reflected compared to a black body.
  • D. The fraction of radiation absorbed compared to a black body.

3. What is the accepted average value of the Earth's albedo?

  • A. 0.3
  • B. 0.4
  • C. 0.6
  • D. 0.7
 The Earth - photo

4. The 'solar constant' S is a key value for considering global warming and the greenhouse effect. The value for Earth is taken to be about 1.4 kW m-2.

Which of these best describes the solar constant?

  • A. The intensity of radiation from the Sun reflected by the Earth's atmosphere.
  • B. The intensity of radiation from the Sun reflected by the Earth's surface.
  • C. The intensity of radiation from the Sun incident on the Earth's atmosphere.
  • D. The intensity of radiation from the Sun absorbed by the Earth's surface.
5. The Earth presents a circular cross-section to the Sun, recieving radiation of intensity S all year, where S is the solar constant. However this radiation is spread over the entire sphere of the Earth's surface. rotating Earth Gif

This means the global average annual intensity on the upper atmosphere is:

  • A. S/8
  • B. S/4
  • C. S/2
  • D. S (no reduction)

6. Both the Earth and the Sun can be considered as black bodies of different surface temperature. Which of the following best describes the peak wavelength emitted by the Sun and Earth acting as black bodies?

Sun Earth
A
 visible visible
B
 infrared visible
C
 visible infrared
D
 infrared infrared

7. Which of the following is a major greenhouse gas in the atmosphere?

  • A. Water vapour
  • B. Helium
  • C. Nitrogen
  • D. Oxygen

8. Carbon dioxide is a major greenhouse gas. Which of the following statements best describes the action of carbon dioxide in the atmosphere?

  • A. It absorbs a wide spectrum of radiation from the Earth, and then re-radiates this in all directions.
  • B. It absorbs a selective spectrum of radiation from the Earth, and then re-radiates this in all directions.
  • C. It absorbs a wide spectrum of radiation from the Earth, and then re-radiates this back down to Earth.
  • D. It absorbs a selective spectrum of radiation from the Earth, and then re-radiates this back down to Earth.

9. Greenhouse gas molecules absorb energy from photons when the natural frequency of the molecule matches the frequency of the photon. This effect is called..

  • A. the enhanced greenhouse effect
  • B. resonance
  • C. interference
  • D. quantisation

10. The diagram below shows a simplified model of the Earth's climate.

simplified climate model with numbers

  

What is the heat transfer shown by the arrow labelled X?

  • A. 190 W m-2
  • B. 150 W m-2
  • C. 100 W m-2
  • D. 90 W m-2