Stars & The Universe (Cambridge O Level Physics)

Topic Questions

1a
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3 marks

Explain the term galactic redshift.

1b
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2 marks

Explain why galactic redshift is considered as evidence supporting the Big Bang theory.

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2a
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1 mark

Starting with the largest, list the following in order of decreasing size

 
Galaxy    Sun   Universe    Jupiter
2b
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2 marks

State the stages in the life cycle of a star the size of the Sun after the main sequence in the gaps below

Main sequence

...................................

...................................

2c
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4 marks

State 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 ...................................

2d
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2 marks

After 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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3a
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1 mark

State the approximate diameter of the Milky Way in light years.

3b
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2 marks

Nuclear 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 ...........................

3c
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2 marks

Redshift is detected in the galaxies Virgo A and Messier 90. 

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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4a
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6 marks

Rearrange the stages of the life cycle of a star into the correct order.

 
1 white dwarf
2 planetary nebula
3 protostar
4 main sequence star
5 interstellar clouds of gas and dust (stellar nebula)
6 red giant

4b
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2 marks

A 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. 

6-2-5b-e-main-sequence-star-forces

(i)
State the name of the force pulling inwards.
[1]
 
(ii)
Explain what causes the force pushing outwards.
[1]
4c
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2 marks

Two 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. 

1 solar mass = mass of the Sun

4d
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1 mark

State what is meant by a supernova.

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1a
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2 marks

State and explain the main piece of evidence which supports the Big Bang Theory of the origin of the Universe.

1b
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4 marks

Calculate the distance of 50 light-years in metres.

Speed of light = 3.0 × 108 m/s.

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2a
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4 marks

The ‘big bang’ theory is one theory explaining the origin of the Universe.

6-2-4a-h-size-of-universe-time-graph

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]

2b
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2 marks

Explain why our understanding of the very earliest moments of the Universe is unreliable.

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3a
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2 marks

Nuclear 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. 

Explain how this can be the case.

3b
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3 marks

From 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.

6-2-5b-h-hubbles-law-graph-p-and-q

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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1a
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3 marks

The Sun is our nearest star.

 
(i)
State the three main forms of electromagnetic radiation emitted by the Sun.
[2]
 
(ii)
State the two main elements that are found in the Sun.
[1]
1b
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3 marks

State and explain what can be deduced from the ‘redshift’ observed by astronomers in the light from all distant galaxies.

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2a
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3 marks

Describe and explain how a stable star is formed.

2b
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5 marks

Some main sequence stars become black holes. 

Describe the evolution of a main sequence star to the point at which it becomes a black hole. 

2c
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2 marks

State and explain whether the Sun will eventually become a black hole. 

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3a
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2 marks

Describe nuclear fusion in stars.

3b
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5 marks

Derive the distance of 1 light year in metres.

Speed of light = 3.0 × 108 m/s

3c
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2 marks

The 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.

3d
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4 marks

Below are some statements related to Cosmology.

  1. Galaxies are made of up millions of stars
  2. The Sun is a planet because it has a core
  3. Other stars that make up the Milky Way are much further away from the Earth than the Sun is from the Earth
  4. There may be other galaxies in the Milky Way

Identify which of the statements are false and explain why.

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4a
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2 marks

The 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.

4b
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3 marks

Describe what happens to stars of similar mass to the Sun at the end of the stable part of their life cycle.

4c
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3 marks

The orbital speed of Earth around the Sun is 30 km/s. Use this value to calculate the distance of Earth from the Sun. 

Show your working. State the unit of your answer.

distance = ..................................... unit = .......... 

4d
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5 marks

The light emitted by distant galaxies show various amounts of redshift.
 

(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.

q10d-cie-ol-physics-specimen-paper-2-sq

Fig. 10.1
 

State what Fig. 10.1 enables the astronomer to deduce about galaxy P and galaxy Q.

Explain the astronomer’s reasons in your answer

   [2]

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