AQA GCSE Physics 8463: Space physics – Practice Questions

These are original questions written for Marlbridge, for revision and practice on this content. They are not reproduced past-paper questions, and they do not replicate the exam’s exact structure, question count or mark tariffs – examination boards hold copyright in their own papers. Use these alongside the official past papers from your board or school.

These questions cover Topic 8, Space physics (sections 4.8.1 and 4.8.2), of the AQA GCSE Physics (8463) specification, for first teaching 2016 with exams from June 2018 (version 1.1). Space physics is examined on Paper 2 at Foundation and Higher tier every May/June. Question 6 and part 7(c) test the Higher tier only statements in 4.8.1.3 and are labelled; everything else is for both tiers. Calculators are allowed on both papers.

Learn the content first in the study guide and the revision notes. The course hub is AQA GCSE Physics and the printable checklist lists every statement.

Questions

1. This question is about the solar system.

(a) State the name of the only star in the solar system. [1] (b) State what is meant by a natural satellite. [1] (c) Name the galaxy that the solar system is part of. [1]

2. The Sun is a main sequence star.

(a) Describe how the Sun formed. [2] (b) Explain why the Sun stays the same size for a long period of time. [3]

3. These are the stages in the life cycle of a star the same size as the Sun, in the wrong order:

white dwarf – main sequence star – red giant – protostar – black dwarf – nebula

(a) Write the stages in the correct order, starting with the nebula. [2] (b) State what decides which life cycle a star follows. [1]

4. A star has a mass about twenty times the mass of the Sun.

Describe the life cycle of this star after it leaves the main sequence, and explain how stars like this produce elements and spread them through the universe. [6]

5. The Moon and a weather satellite both orbit the Earth. The Earth orbits the Sun.

(a) Name the force that keeps all three in orbit. [1] (b) Give one similarity between the Earth and the Moon, other than the force in (a). [1] (c) Give two differences between the Moon and the weather satellite. [2]

6. (Higher tier only) A satellite moves around the Earth in a circular orbit at a constant speed.

Explain why the satellite is accelerating. [3]

7. A satellite moves in a circular orbit of radius 7.00 × 10⁶ m. It takes 5860 s to complete one orbit.

(a) Calculate the distance the satellite travels in one orbit. [2] (b) Calculate the orbital speed of the satellite. Give your answer to 3 significant figures. [2] (c) (Higher tier only) The satellite is moved into a stable circular orbit of larger radius. State and explain how its speed changes. [2]

8. A dark line in the spectrum of a gas has a wavelength of 500 nm when measured in a laboratory. The same line is observed in the light from two galaxies:

Galaxy	Observed wavelength (nm)
X	520
Y	545

(a) Calculate the percentage increase in wavelength for galaxy X. [2] (b) Calculate the percentage increase in wavelength for galaxy Y. [1] (c) Explain which galaxy is further from the Earth. [2]

9. An astronomer measures the speed at which four galaxies are moving away from the Earth.

Distance from Earth (× 10²⁴ m)	1.5	3.0	4.5	6.0
Speed away from Earth (km/s)	3300	6600	9900	13 200

(a) Describe the relationship between speed and distance. Use data from the table. [2] (b) Predict the speed of a galaxy 7.5 × 10²⁴ m from the Earth. [1] (c) Another galaxy is moving away at 5500 km/s. Estimate its distance from the Earth. [1] (d) Explain how data like this supports the Big Bang theory. [3]

10. The Big Bang theory is the accepted model for the origin of the universe.

(a) Explain how scientists used observations to arrive at the Big Bang theory. [3] (b) State what observations of supernovae since 1998 suggest about distant galaxies. [1] (c) Give one example of something about the universe that scientists still do not understand. [1]

11. A spectral line has a wavelength of 400 nm in the laboratory. In light from a distant galaxy the same line has a wavelength of 436 nm. The speed of light is 3.00 × 10⁸ m/s.

(a) Calculate the frequency of the line measured in the laboratory. [2] (b) Calculate the frequency of the line observed from the galaxy. [1] (c) State what the change in wavelength tells you about the motion of the galaxy. [2] (d) The light from the galaxy also shows lines from gold, an element heavier than iron. Explain how gold came to be in this galaxy. [3]

Answers

1. (a) The Sun [1] (b) A moon; a natural object that orbits a planet [1] (c) The Milky Way [1] Examiner insight: “A satellite” alone does not score (b) – the mark needs “moon” or the idea of orbiting a planet.

2. (a) A cloud of dust and gas (nebula) [1] was pulled together by gravitational attraction [1] (b) Gravity pulls the material inwards (gravitational collapse) [1]; energy released by fusion pushes the material outwards (expansion) [1]; these are balanced, so the star is in equilibrium [1] Examiner insight: Each mark in (b) is a separate idea; naming both effects without saying they balance caps the answer at 2.

3. (a) nebula → protostar → main sequence star [1] → red giant → white dwarf → black dwarf [1] (b) The size (mass) of the star [1] Examiner insight: Each mark in (a) is for a correct group of three in the right order; one swapped pair loses only that group’s mark.

4. Indicative points (a levels-of-response answer needs a clear, logical sequence):

• The star swells to become a red super giant [1]
• It then explodes as a supernova [1]
• It leaves behind a neutron star or a black hole [1]
• Fusion in the star forms elements from hydrogen and helium up to iron [1]
• Elements heavier than iron are produced in the supernova [1]
• The explosion distributes the elements throughout the universe [1] Examiner insight: A 6-mark answer is marked on levels: for the top level you need both the life-cycle sequence and the element-formation explanation, linked in a logical order.

5. (a) Gravity [1] (b) Any one: both are natural; both move in orbits; both are part of the solar system [1] (c) Any two: the Moon is natural, the weather satellite is made by people [1]; the Moon is much larger [1]; accept: the weather satellite has a use such as monitoring weather, the Moon does not Examiner insight: A difference needs both sides stated or clearly implied (“the Moon is natural but the satellite is artificial”); “it is artificial” alone is ambiguous.

6. The direction of the satellite changes continuously [1]; velocity is a vector, so the velocity changes (even though the speed does not) [1]; a change in velocity is an acceleration, caused by gravity acting towards the centre of the orbit [1] Examiner insight: Writing “its speed changes” contradicts the question and loses the second mark; the key word is velocity.

7. (a) distance = 2 × π × r = 2 × π × 7.00 × 10⁶ [1] = 4.40 × 10⁷ m [1] (b) v = s / t = 4.40 × 10⁷ / 5860 [1] = 7510 m/s (7.51 × 10³ m/s) [1] (c) The speed decreases [1]; for a stable orbit, a larger radius goes with a smaller speed [1] Examiner insight: Allow error carried forward from (a) into (b); the method mark in (b) is for dividing your distance by the time, so show it.

8. (a) Increase = 520 − 500 = 20 nm; percentage = 20 / 500 × 100 [1] = 4.0 % [1] (b) 45 / 500 × 100 = 9.0 % [1] (c) Galaxy Y [1]; it has the larger red-shift, so it is moving away faster, and faster galaxies are further away [1] Examiner insight: Percentage change must be divided by the laboratory value; dividing by the observed wavelength loses the accuracy mark in (a).

9. (a) Speed increases as distance increases [1]; the speed is directly proportional to distance, e.g. doubling distance from 1.5 to 3.0 doubles speed from 3300 to 6600 km/s [1] (b) 2200 × 7.5 = 16 500 km/s [1] (c) 5500 / 2200 = 2.5 × 10²⁴ m [1] (d) Galaxies are moving away, and further ones faster, so space (the universe) is expanding [1]; so the universe was smaller in the past [1]; so it began from a very small region that was extremely hot and dense [1] Examiner insight: “Directly proportional” in (a) needs evidence from the data; quoting a pair of values that doubles together earns the second mark.

10. (a) Scientists observed the red-shift of light from many galaxies [1]; they found a pattern: more distant galaxies are moving away faster [1]; they proposed the Big Bang model because it explains these observations [1] (b) Distant galaxies are receding ever faster (the expansion is speeding up) [1] (c) Dark mass (dark matter) or dark energy [1] Examiner insight: In (a) the three marks follow observe → pattern → model; describing the Big Bang itself without mentioning the observations scores at most 1.

11. (a) f = v / λ = 3.00 × 10⁸ / 400 × 10⁻⁹ [1] = 7.50 × 10¹⁴ Hz [1] (b) f = 3.00 × 10⁸ / 436 × 10⁻⁹ = 6.88 × 10¹⁴ Hz [1] (c) The wavelength has increased (red-shift) [1], so the galaxy is moving away from the Earth [1] (d) Gold is heavier than iron, so it was produced in a supernova [1]; the supernova was the explosion of a star much more massive than the Sun [1]; the explosion distributed the gold through the universe, where it became part of the material in this galaxy [1] Examiner insight: Converting nm to m (× 10⁻⁹) is essential in (a); an answer out by a power of ten loses the accuracy mark but keeps the method mark if the equation is correct.

Where marks are usually lost

• Saying the Sun formed from an explosion instead of gravity pulling a nebula together.
• Naming gravity and fusion but not saying they are balanced (equilibrium).
• Putting “red giant” in the massive-star sequence instead of “red super giant”.
• Stating that all elements come from supernovae; only elements heavier than iron do.
• Missing the “distributes the elements” point about supernovae.
• (Higher tier) Writing that the speed changes in a circular orbit, instead of the velocity.
• (Higher tier) Saying a faster satellite needs a larger orbit; it is the other way round.
• Dividing a wavelength change by the observed value rather than the laboratory value.
• Forgetting to convert nanometres to metres before using v = f λ.
• Describing a trend in a table without quoting any data.

Next steps

• Space physics revision notes
• Space physics study guide
• AQA GCSE Physics exam preparation
• AQA GCSE Physics course hub
• Printable checklist
• All free 10-minute diagnostics
• Book a free trial class

Official syllabus

AQA GCSE Physics (8463) specification, for first teaching 2016, exams from June 2018, version 1.1, published by AQA – section 4.8 Space physics (4.8.1 Solar system; stability of orbital motions; satellites, and 4.8.2 Red-shift).