Available practice: 76 of 80 marks. Parts 10(c) await marking support. Scores cover available parts only. Theory: answer each printed part. For drawings, upload a clear photo of your sketch on the supplied figure; show working and units for calculations.
Astronomical distances are measured in light-years.
(a)(i)State what is meant by a “light-year”.
Answer guidance
State A short answer. No explanation is needed, and adding one cannot earn extra marks.
[1 mark]
(a)(ii)The Sun is one star in the Milky Way. State the approximate diameter of the Milky Way in light-years.
Answer guidance
State A short answer. No explanation is needed, and adding one cannot earn extra marks.
[1 mark]
(b)(i)Using Fig. 10.1 and the word list (nebula, neutron star, protostar, red giant, supernova, white dwarf), complete the three blanks after the red-supergiant stage.
Answer guidance
Using You must use the thing it names. An answer that reaches the right value another way may not score.
[2 marks]
(b)(ii)State the stage in a star’s life cycle when heavy elements form.
Answer guidance
State A short answer. No explanation is needed, and adding one cannot earn extra marks.
[1 mark]
(c)The Big Bang occurred about 14 billion years ago. Explain one observation that supports the Big Bang Theory.
Answer guidance
Explain Give reasons, not just what happens. Each distinct reason is usually worth a mark.
[4 marks]
This part can’t be checked automatically yet. Compare your own working with the explanation below.
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Worked explanation
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One correct answer. This part can’t be checked automatically yet, so compare your own working with it.
Observation: light from distant galaxies is red-shifted, and more distant galaxies show a larger red shift. This indicates that galaxies are moving away from us, with more distant ones receding faster. Extrapolating the expansion backwards places the galaxies much closer together in an earlier, denser universe, supporting a common hot beginning.