Topic 13 Practice Paper: Space physics — question paper

Section A: Multiple-choice questions[10 marks]

Choose one answer for each question. Each question is worth 1 mark.

1. 1

   Which row correctly orders the first four planets from the Sun?

   	Order
   A	Mercury, Earth, Venus, Mars
   B	Mercury, Venus, Earth, Mars
   C	Venus, Mercury, Mars, Earth
   D	Earth, Venus, Mercury, Mars
2. 2

   The pattern of seasons on Earth is caused by

   1. Athe Earth’s distance from the Sun changing through the year
   2. Bthe Moon blocking sunlight at certain times of year
   3. Cthe tilt of the Earth’s axis as it orbits the Sun
   4. Dchanges in the Sun’s temperature
   ( )
3. 3

   The planets continue orbiting the Sun year after year because

   1. AThe Sun’s gravitational attraction
   2. BMagnetism
   3. CAir pressure
   4. DElectrostatic attraction
   ( )
4. 4

   As distance from the Sun increases, the orbital speeds of the planets

   1. Aincrease
   2. Bstay the same
   3. Cbecome zero
   4. Ddecrease
   ( )
5. 5

   A satellite orbits at r = 1.2 × 10⁷ m with period T = 1.0 × 10⁴ s. Its orbital speed is about

   1. A1.2 × 10³ m/s
   2. B7.5 × 10³ m/s
   3. C7.5 × 10¹⁰ m/s
   4. D8.3 × 10⁻⁴ m/s
   ( )
6. 6

   A comet in an elliptical orbit travels fastest when it is

   1. Afurthest from the Sun
   2. Bexactly halfway along its orbit
   3. Cclosest to the Sun
   4. Dmoving directly away from the Sun
   ( )
7. 7

   Stable stars, including the Sun, are powered by

   1. Athe fusion of hydrogen into helium
   2. Bthe fission of heavy elements
   3. Cburning of oxygen in their atmospheres
   4. Dfriction between the star and space
   ( )
8. 8

   The final remnant of a star with about the Sun’s mass is a

   1. Aneutron star
   2. Bwhite dwarf
   3. Cblack hole
   4. Dred supergiant
   ( )
9. 9

   Redshift in the light from distant galaxies shows that their wavelengths have increased, which means the galaxies are

   1. Amoving towards us
   2. Bmerging with the Milky Way
   3. Cbecoming hotter
   4. Dreceding from us
   ( )
10. 10

    The cosmic microwave background radiation (CMBR) supports the Big Bang Theory because it

    1. Ais sunlight reflected back to Earth
    2. Bcomes only from the direction of the Milky Way’s centre
    3. Cwas produced shortly after the Universe formed and stretched into microwaves by the expansion
    4. Dis radiation emitted by red giants
    ( )

Section B: Structured questions[20 marks]

Answer all questions in the spaces provided.

1. 11

   The Earth, Moon and Sun system explains several familiar cycles.

   1. (a)

      Explain the cycle of day and night.

      [2]
   2. (b)

      Explain the cycle of the seasons.

      [2]
   3. (c)

      State the period of the Moon’s orbit around the Earth and the cycle it explains.

      [2]
2. 12

   A communication satellite orbits the Earth at an average orbital radius of 4.2 × 10⁷ m with a period of 24 hours (86 400 s). Light travels at 3.0 × 10⁸ m/s.

   1. (a)

      Calculate the average orbital speed of the satellite.

      [3]
   2. (b)

      The satellite is directly above an observer. Calculate the time a signal takes to travel from the observer straight up to the satellite.

      [2]
   3. (c)

      Explain why a TV signal sent up to the satellite and back down arrives a fraction of a second late.

      [1]
3. 13

   The Solar System contains the Sun, eight planets, dwarf planets, asteroids, moons and comets.

   1. (a)

      Name the four planets nearest the Sun and state what they have in common.

      [2]
   2. (b)

      In the accretion model, state what force pulled the gas and dust cloud together and what formed as the rotating cloud flattened.

      [2]
   3. (c)

      State where the asteroid belt lies.

      [1]
4. 14

   Observations of distant galaxies show their light is redshifted. A particular galaxy recedes at 5.5 × 10⁵ m/s and lies 2.5 × 10²³ m away.

   1. (a)

      State what redshift is, and what it provides evidence for.

      [2]
   2. (b)

      Use this galaxy’s data to calculate the Hubble constant.

      [1]