1a
3 marks
3 marksExplain the term galactic redshift.
1b2 marks
2 marksExplain why galactic redshift is considered as evidence supporting the Big Bang theory.
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Stars & The Universe (Cambridge O Level Physics)
Exam Questions
2 hours22 questions
2a1 mark
1 markStarting with the largest, list the following in order of decreasing size
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| Galaxy    Sun   Universe   Jupiter |
2b2 marks
2 marksState the stages in the life cycle of a star the size of the Sun after the main sequence in the gaps below
Main sequence
↓
...................................
↓
...................................
2c4 marks
4 marksState the stages in the life cycle of a star much greater than the size of the Sun after the main sequence in the gaps below
Main sequence
↓
...................................
↓
...................................
↓
................................... or ...................................
2d2 marks
2 marksAfter a supernova explosion, a nebula can form from the leftover material.
Explain what forms in a nebula after it has been created by a supernova.
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3a1 mark
1 markState the approximate diameter of the Milky Way in light years.
3b2 marks
2 marksNuclear fusion occurs in the core of a stable star.
Complete the sentence explaining nuclear fusion.
Nuclear reactions in the core of a star involve the fusion of ........................... into ...........................
3c2 marks
2 marksRedshift is detected in the galaxies Virgo A and Messier 90.Â
Messier 90 is closer to the Earth than Virgo A.
State and explain which galaxy is moving away from Earth faster.
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4a6 marks
6 marksRearrange the stages of the life cycle of a star into the correct order.
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| 1 | white dwarf |
| 2 | planetary nebula |
| 3 | protostar |
| 4 | main sequence star |
| 5 | interstellar clouds of gas and dust (stellar nebula) |
| 6 | red giant |
4b2 marks
2 marksA star can be in its main sequence phase for billions of years.
Fig 1.1 shows the forces acting on the Sun during this stable stage of its life cycle.Â
(i)
State the name of the force pulling inwards.
[1]
Â
(ii)
Explain what causes the force pushing outwards.
[1]
4c2 marks
2 marksTwo stars, Alpha Centauri B and Betelgeuse are 0.9 and 16.5 solar masses respectively.
State which star could eventually become a neutron star. Explain your reasoning.Â
1 solar mass = mass of the Sun
4d1 mark
1 markState what is meant by a supernova.
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1a3 marks
3 marksThe Sun is our nearest star.
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(i)
State the three main forms of electromagnetic radiation emitted by the Sun.
[2]
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(ii)
State the two main elements that are found in the Sun.
[1]
1b3 marks
3 marksState and explain what can be deduced from the ‘redshift’ observed by astronomers in the light from all distant galaxies.
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2a3 marks
3 marksDescribe and explain how a stable star is formed.
2b5 marks
5 marksSome main sequence stars become black holes.Â
Describe the evolution of a main sequence star to the point at which it becomes a black hole.Â
2c2 marks
2 marksState and explain whether the Sun will eventually become a black hole.Â
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3a2 marks
2 marksDescribe nuclear fusion in stars.
3b5 marks
5 marksDerive the distance of 1 light year in metres.
Speed of light = 3.0 × 108 m/s
3c2 marks
2 marksThe Milky Way is approximately 100 000 light years in diameter.
Calculate the time it would take a spacecraft travelling at the speed of light to travel from one side of the Milky Way to the other.
3d4 marks
4 marksBelow are some statements related to Cosmology.
- Galaxies are made of up millions of stars
- The Sun is a planet because it has a core
- Other stars that make up the Milky Way are much further away from the Earth than the Sun is from the Earth
- There may be other galaxies in the Milky Way
Identify which of the statements are false and explain why.
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4a2 marks
2 marksThe Sun is a star in a stable part of its life cycle.
Using ideas about forces, explain how the Sun remains stable in this part of its life cycle.
4b3 marks
3 marksDescribe what happens to stars of similar mass to the Sun at the end of the stable part of their life cycle.
4c3 marks
3 marksThe orbital speed of Earth around the Sun is 30 km/s. Use this value to calculate the distance of Earth from the Sun.Â
Show your working. State the unit of your answer.
distance = ..................................... unit = ..........Â
4d5 marks
5 marksThe light emitted by distant galaxies show various amounts of redshift.
Â
(i)
State the name of the galaxy that contains our Sun.
. [1]
(ii)
State what is meant by redshift and describe how it is caused.
 [2]
(iii)
An astronomer compares the spectrum of light emitted by the Sun with the spectrum of light emitted by distant galaxies P and Q.
Fig. 10.1 shows the same four lines as observed in all three spectrums.
Fig. 10.1 shows the same four lines as observed in all three spectrums.
Fig. 10.1
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State what Fig. 10.1 enables the astronomer to deduce about galaxy P and galaxy Q.
Explain the astronomer’s reasons in your answer
Explain the astronomer’s reasons in your answer
  [2]
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1a2 marks
2 marksState and explain the main piece of evidence which supports the Big Bang Theory of the origin of the Universe.
1b4 marks
4 marksCalculate the distance of 50 light-years in metres.
Speed of light = 3.0 × 108 m/s.
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2a4 marks
4 marksThe ‘big bang’ theory is one theory explaining the origin of the Universe.
Fig 1.1
(i)
Sketch the graph of the size of the Universe with time on Fig 1.1.
[2]
(ii)
Explain how your graph in part (i) supports the Big Bang Theory.
[2]
2b2 marks
2 marksExplain why our understanding of the very earliest moments of the Universe is unreliable.
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3a2 marks
2 marksNuclear fusion reactions in the Sun fuse hydrogen to make helium.
In the Solar System, the inner planets, such as the Earth, contain elements which are heavier than the elements hydrogen and helium.Â
Explain how this can be the case.
3b3 marks
3 marksFrom the data collected, the graph that links the speed of a galaxy with the distance of the galaxy from the Earth is shown in Fig. 1.1.
Fig 1.1
Describe how the visible light spectrum from galaxy Q looks different from the visible light spectrum from galaxy P.
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