Lesson 3.7.2.4

3.7.2.4 Orbits of planets and satellites Quiz: AQA Physics, Unit 7

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.7.2.4, Orbits of planets and satellites: 20 multiple choice questions for the AQA Physics (7408), Unit 7: Fields and their consequences (A-level only), written with Revision Ninja.

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The 20 questions

  1. For a satellite in a circular orbit of radius r about a body of mass M, the orbital speed is:

    • v = sqrt(GM r)
    • v = GM / r
    • v = GM / sqrt(r)
    • v = sqrt(GM / r)

  2. Kepler's third law for circular orbits states that:

    • T^2 is proportional to r^3
    • T^2 is proportional to r
    • T is proportional to r^3
    • T is proportional to r

  3. The total energy of a satellite in a circular orbit of radius r is:

    • positive, E = +GMm / (2r)
    • negative, E = -GMm / (2r)
    • E = GMm r
    • E = -GMm / r

  4. How does a satellite's kinetic energy compare to its gravitational potential energy magnitude?

    • Twice as large
    • Four times larger
    • Equal in magnitude
    • Half as large

  5. The escape velocity from a body of mass M and radius r is:

    • v = sqrt(2GM / r)
    • v = sqrt(GM / (2r))
    • v = sqrt(GM / r)
    • v = 2GM / r

  6. What is the orbital period of a geostationary satellite around Earth?

    • 24 hours
    • 12 hours
    • 365 days
    • 90 minutes

  7. What is the approximate orbital period of a satellite in low Earth orbit?

    • 90 minutes
    • 10 minutes
    • 24 hours
    • 12 hours

  8. A satellite orbits at radius 4.2 x 10^7 m about Earth, where GM = 4.0 x 10^14 m^3 s^-2. Estimate its period.

    • about 12 hours
    • about 240 hours
    • about 1.5 hours
    • about 24 hours

  9. A satellite orbits at radius 7.0 x 10^6 m about Earth, where GM = 4.0 x 10^14 m^3 s^-2. What is its orbital speed?

    • about 11 km s^-1
    • about 5.3 km s^-1
    • about 7.6 km s^-1
    • about 3.8 km s^-1

  10. Using GM = 4.0 x 10^14 m^3 s^-2 and Earth's radius 6.4 x 10^6 m, estimate the escape velocity from the surface.

    • about 5.6 km s^-1
    • about 11 km s^-1
    • about 7.9 km s^-1
    • about 15.8 km s^-1

  11. A 1000 kg satellite orbits at radius 7.0 x 10^6 m where GM = 4.0 x 10^14 m^3 s^-2. What is its total energy?

    • about +2.9 x 10^10 J
    • about -2.9 x 10^10 J
    • about -1.4 x 10^7 J
    • about -5.7 x 10^10 J

  12. The orbital radius of a satellite is doubled. Its orbital period becomes approximately:

    • 4 times greater
    • 1.4 times greater
    • 2 times greater
    • 2.8 times greater

  13. Compared with the orbital speed of a satellite at a given radius, the escape speed from that radius is:

    • twice as great
    • about 1.4 times greater
    • equal
    • half as great

  14. On a log-log plot of period T against orbital radius r for planets orbiting the same star, the gradient is:

    • 0.5
    • 2
    • 1.5
    • 3

  15. As a satellite's orbital radius increases, what happens to its orbital speed?

    • Increases
    • Decreases
    • Becomes zero
    • Stays constant

  16. When a satellite moves to a lower circular orbit, what happens to its kinetic energy?

    • Becomes zero
    • Stays constant
    • Decreases
    • Increases

  17. A satellite in a circular orbit at radius r1 moves to a circular orbit at radius 4 r1. Its period increases by a factor of:

    • 16
    • 2
    • 4
    • 8

  18. A 500 kg satellite is in circular orbit at radius 8.0 x 10^6 m, where GM = 4.0 x 10^14 m^3 s^-2. How much energy must be supplied to move it to infinity?

    • about 1.3 x 10^10 J
    • about 1.3 x 10^7 J
    • about 2.5 x 10^10 J
    • about 6.3 x 10^9 J

  19. What causes astronauts in an orbiting space station to feel weightless?

    • Centrifugal force
    • Atmospheric shielding
    • Zero gravity
    • Continuous free fall

  20. Using GM = 4.0 x 10^14 m^3 s^-2 and a period of 24 hours, estimate the radius of a geostationary orbit.

    • about 3.8 x 10^8 m
    • about 1.0 x 10^5 m
    • about 4.2 x 10^7 m
    • about 6.4 x 10^6 m

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