IGCSE Physics Past Years Exam Questions: Astrophysics

Analysed the International GCSE past papers and grouped the questions by topic. Here, you will find questions relating to the topic – Astrophysics. Use these to familiarise, practice and prepare for your IGCSE Physics examination.

What you need to know

Use the list below as a quick recap for what you need to know before attempting the past year exam questions under this topic. This is based on Edexcel International GCSE in Physics (4PH1) specification with first teaching Sept 2017 and first examination June 2019.

Paper 1 and 2: (8) Astrophysics

Paper 1 covers all the topics except where it is marked “Paper 2 only” while Paper 2 covers all topics.

A. Units

• kilogram (kg), metre (m), metre/second (m/s), metre/second² (m/s²), newton (N), second (s), newton/kilogram (N/kg)

B. Motion in the universe

• the universe is a collection of billions of galaxies
• a galaxy is a collection of billions of stars
• our solar system is in the Milky Way galaxy
• understand why gravitational field strength, g, varies, on other planets and moons
• explain that the gravitational force causes moon to orbit planets, planets to orbit the sun, artificial satellites to orbit Earth and comets to orbit the sun
• the differences in the orbits of comets, moons and planets
• the relationship between orbital speed, orbital radius and time period. v = (2 ×π × r)/ T

C. Stellar evolution

• understand how stars can be classified according to colour
• know that a star’s colour is related to its surface temperature.
• describe the evolution of stars with a mass similar to the Sun through stages: nebular, star (main sequence), red giant, white dwarf.
• describe the evolution of stars with a mass larger than the Sun

(Paper 2 only)

• understand how the brightness of a star at a standard distance can be represented using absolute magnitude
• draw the main components of the Hertzsprung-Russell diagram (HR diagram)

D. Cosmology (Paper 2 only)

• the past evolution of the universe and the main arguments in favour of the Big Bang Theory
• evidence for the Big Bang theory (red-shift and cosmic microwave background CMB radiation)
• describe that if a wave source is moving relative to an observer there is a change in observed frequency and wavelength
• know the equation relating the change in wavelength to the velocity of a galaxy
• change in wavelength/reference wavelength = velocity of a galaxy/speed of light, (λ−λ₀)/λ₀ =Δλ/λ₀=v/c
• describe red-shift in light received from galaxies at different distances away from Earth
• be able to explain why red shift provides evidence for the expansion of the Universe.

June 2019 Paper 1P Q8

8. Schiaparelli is a spacecraft that was sent to Mars in 2016.

(a) Schiaparelli slowed down as it fell vertically through the atmosphere of Mars.

(i) Draw labelled arrows on the diagram to show the forces acting on Schiaparelli as it fell.

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(ii) Schiaparelli then opened a parachute to slow down.

Explain how the space craft reached a low terminal velocity after opening its parachute. 

Use ideas about forces in your answer.(4)

(b) The parachute was disconnected when Schiaparelli was at a height of 2.0 m from the surface of Mars and travelling at a speed of 0.45 m/s.

Calculate the speed of the spacecraft just before it hits the surface of Mars. (4)

[acceleration of free-fall on Mars = 3.4 m/s²]

(c) Suggest why Mars has a lower gravitational field strength than Earth.(1)

(Total for Question 8 = 12 marks)

June 2019 Paper 1PR Q1

1. This question is about stars.

(a) The diagram shows the orbits of two astronomical objects around a star.

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(i) Add a labelled arrow to the diagram to show the type of force from the start acting on object A (2)

(ii) What is object A? (1)

A. a comet
B. a galaxy
C. a moon
D. a planet

(iii) What is object B?(1)

A. a comet
B. a galaxy
C. a moon
D. a planet

(b) State the name given to a large collection of billions of stars (1)

(c) Physicists classify stars according to their colour.

Each group of stars of similar colour is called a spectral class.

The table gives information about colour and surface temperature for three spectral classes of stars

The Sun belongs to spectral class G.

Complete the table by suggesting values for the missing surface temperatures.(2)

(d) There are stars in the universe with masses much greater than the mass of the Sun.

Describe what happens to these high-mass stars when they leave the main sequence stage of their evolution.(3)

(Total for Question 1 = 10 marks)

June 2019 Paper 2P Q1

1 (a) Which force is responsible for keeping satellites in orbit? (1)

A electrostatic 
B gravitational 
C magnetic
D nuclear 

(b) Which of these is the largest? (1)

A galaxy
B planet
C star
D universe 

(c) Which of these represents the brightness of stars at a standard distance? (1)

A  absolute magnitude 
B  colour 
C  diameter 
D  temperature 

Total for Question 1 = 3 marks 

June 2019 Paper 2 Q7

7 (a) Give two pieces of evidence for the Big Bang theory. (2)

(b) Explain how this evidence supports the Big Bang theory. (4)

Total for Question 7 = 6 marks 

June 2019 Paper 2PR Q4

4 A Hertzsprung‐Russell diagram shows how different astronomical objects may be classified according to their colour and absolute magnitude. 

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The diagram shows three stages of evolution for stars of similar mass to the Sun. 

Describe the evolution of stars of similar mass to the Sun.

You should refer to the temperature and brightness of the stars in your answer. (6)

Total for Question 4 = 6 marks 

January 2020 Paper 1 Q12

12 The planets Mars and Saturn orbit around the same star, the Sun. 

(a) The diagram shows the orbital paths of Mars and Saturn. 

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Draw an orbital path of a comet on the diagram. (2)

(b) The table gives some information about the orbits of Mars and Saturn. 

Mars completes a number of orbits in the time it takes for Saturn to complete one orbit. 

Calculate the number of orbits that Mars completes in the time it takes for Saturn (5)

number of orbits = ……………………………………………………..

Total for Question 12 = 7 marks 

January 2020 Paper 1PR Q4

4 Betelgeuse is a red supergiant star.

Betelgeuse has a mass that is much larger than the Sun. Describe the evolution of 

Betelgeuse through its entire life cycle. (5)

Total for Question 4 = 5 marks 

January 2020 Paper 2P Q6

6 This question is about stars.

(a) Astronomers measure the absolute magnitude of stars.

State what is meant by the term absolute magnitude. (2)

(b) The evolution of stars can be shown on a Hertzsprung‐Russell diagram (HR diagram). 

Complete the HR diagram by 

• labelling the x‐axis
• completing the absolute magnitude scale
• drawing the main sequence, red giant and white dwarf regions (5)

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(Total for Question 6 = 7 marks) 

June 2020 Paper 1P Q3

3 This question is about stars.

(a) Describe the stages in the evolution of a star similar in mass to the Sun. (4)

(b) The process of energy release in the core of a star is different to the process of energy release in a nuclear reactor in a power station. 

Describe how these processes of energy release are different. (3)

(Total for Question 3 = 7 marks) 

June 2020 Paper 1P Q11

11 This question is about satellites and their orbits.

(a) (i) State a difference between an artificial satellite’s orbit and a planet’s orbit. (1)

(ii) State a similarity between an artificial satellite’s orbit and a moon’s orbit. (1)

(b) KALPANA-1 was an artificial satellite used to monitor the weather. 

(i) The diagram shows the orbit of the satellite. 

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KALPANA-1 has an orbital speed of 3.1 km/s and completes one orbit in 24 hours. 

Calculate the height of KALPANA-1’s orbit above the Earth’s surface. (4)

[radius of Earth = 6400 km] 

(ii) The Doppler effect occurs when there is relative motion between the source of waves and the observer of the waves. 

Explain how the Doppler effect causes a change in the observed frequency of the waves. (3)

(iii) Suggest why the radio waves from KALPANA-1 detected on the Earth’s surface are not affected by the Doppler effect. (2)

(Total for Question 11 = 11 marks) 

June 2020 Paper 1PR Q1

1 This question is about astrophysics. 

(a) Complete the sentences by writing a suitable word or phrase in each blank space. (3)

Space and all the galaxies in it is called the …………………………………………………………………………………
A large collection of billions of stars is called a …………………………………………………………………………………
The Sun and its collection of planets and moons is called the ………………………………………………………………………….

(b) The diagram shows the orbit of a comet around the Sun. 

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(i) At which point in its orbit is the comet moving fastest? (1)

A 
B
C
D 

(ii) Name the force that keeps the comet in orbit around the Sun.(1)

(c) The boxes give some units of time and some definitions.

Draw a straight line from each unit of time to its correct definition. (2)

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(Total for Question 1 = 7 marks) 

June 2020 Paper 1PR Q4

4 This question is about Rigel, a very large star with a high surface temperature.

(a) Stars can appear as different colours because of their different surface temperatures. 

Which of these colours shows the highest surface temperature for a star? (1)

A blue-white 
B orange
C red
D yellow 

(b) Describe how a star is formed in a nebula. (2)

(c) Rigel is a main sequence star. 

A star joins the main sequence when nuclear fusion of hydrogen starts in its core. 

Describe the process of nuclear fusion in a star. (3)

(d) Astronomers think that Rigel will become a supernova in the future.

(i) Which property of a star determines whether it will become a supernova? (1)

A colour
B distance from Earth 
C mass
D temperature 

(ii) Describe the evolution of Rigel after it leaves the main sequence. (3)

(Total for Question 4 = 10 marks) 

June 2020 Paper 2PR Q8

8 The Big Bang theory suggests that the Universe is approximately 14 billion years old. 

(a) Describe the evolution of the Universe from the Big Bang until the present day. (3)

(b) Describe the evidence that supports the Big Bang theory. (4)

(Total for Question 8 = 7 marks) 

January 2021 Paper 1P Q1

1 The passage describes the evolution of a star with a mass that is much larger than the mass of the Sun.

Use words or phrases from the box to complete the passage.

Each word or phrase may be used once, more than once, or not at all. (6)

Hydrogen atoms in a nebula move towards each other due to the force of gravity.

As the atoms move towards each other, their ……………………………………………………………………………… energy store increases, which increases the temperature.

If the temperature becomes high enough, nuclear fusion of hydrogen will start and the star enters the ……………………………………………………………………………… stage of its evolution.

When hydrogen fusion stops in the core of the star, the core of the star will start to ……………………………………………………………………………….

This increases the temperature in a layer surrounding the core. Hydrogen fusion restarts in a layer surrounding the core.

This causes the star to ……………………………………………………………………………… and its surface temperature decreases.

The star is now a red super giant. Eventually nuclear fusion stops in the core of the star and the star explodes as a ……………………………………………………………………………… .

The core of the star collapses to form either a ……………………………………………………………………………… or a black hole. 

(Total for Question 1 = 6 marks) 

January 2021 Paper 2P Q6

6 The Hertzsprung-Russell diagram shows the relationship between the absolute magnitude and colour of stars. 

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The position of the Sun is shown on the Hertzsprung-Russell diagram. 

(a)  Star W is a white dwarf. 
Add a W to the Hertzsprung-Russell diagram to show the position of star W. (1)

(b)  Star X is a red giant.
Add an X to the Hertzsprung-Russell diagram to show the position of star X. (1)

(c)  Star Y is a main sequence star that is much larger than the Sun.
Add a Y to the Hertzsprung-Russell diagram to show the position of star Y. (1)

(d) Star Z has the same surface temperature as the Sun, but would be dimmer than the Sun if it were the same distance away from Earth as the Sun. 

Add a Z to the Hertzsprung-Russell diagram to show the position of star Z. (1)

(e) The Moon is the brightest object in the night sky.
Suggest why the Moon cannot be shown on the Hertzsprung-Russell diagram. (1)

(Total for Question 6 = 5 marks) 

January 2021 Paper 1PR Q3

3 The diagram shows two objects orbiting a star. 

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(a) Object X has a circular orbit around the star.

State the type of object that has a circular orbit around a star. (1)

(b) Object Y has an elliptical orbit around the star. 

State the type of object that has an elliptical orbit around a star. (1)

(c) Object X completes an orbit of the star in35days. 

The radius of its orbit is 1.5 × 1011 m. Calculate the orbital speed of object X.  (3)

orbital speed = …………………………………………………….. m/s 

(Total for Question 3 = 5 marks) 

January 2021 Paper 2PR Q6

6 The Big Bang theory describes the evolution of the universe.

(a) Explain how cosmic microwave background radiation (CMBR) supports the Big Bang theory. (2)

(b) Hydrogen gas in a laboratory on Earth emits light with a wavelength of 605 nm.

A distant galaxy contains hydrogen which emits light of the same wavelength.

The wavelength of the light from the distant galaxy is measured as 683 nm on Earth. Calculate the speed of the distant galaxy.(4)
[speed of light = 3.0 × 108 m/s]  

speed = …………………………………………………….. m/s 

(Total for Question 6 = 6 marks) 

2022 Paper 1PR Q6

6 This question is about stars.

(a) Table 1 gives some information about four stars. 

Table 1

(i) Stars can be classified using their surface temperature. 

Complete Table 2 by giving the four stars in order of increasing surface temperature. (3)

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(ii) Name the star in Table 1 that does not follow a similar evolutionary path to the Sun. (1)

(b) The life cycle of a star begins in a nebula.

Describe how a main sequence star is formed from a nebula. (3)

(c) Describe how a main sequence star becomes a white dwarf. (4)

(Total for Question 6 = 11 marks) 

2022 Paper 2P Q3

3 Nuclear fusion is a process that occurs in the core of stars. (a) Which is the best description of nuclear fusion? 

A  large nucleus splitting into two smaller nuclei 
B  nucleus emitting an electromagnetic wave 
C  nucleus releasing a beta particle 
D  two smaller nuclei joining together to form a larger nucleus 

(b) Two nuclei are close together and stationary. 

Explain why these nuclei will move apart. (2)

(c) Describe the conditions needed for fusion to occur in the core of a star. (2)

(Total for Question 3 = 5 marks) 

2022 Paper 2P Q8

8 (a) (i) A galaxy moves away from the Earth at a speed of 3.9 × 104 km/s.

The speed of light is 3.0 × 10⁵ km/s.

Light from the galaxy is emitted with a wavelength of 6.2 × 10⁻⁷ m. 

Calculate the change in the wavelength of the light that is received by an observer on the Earth. (3)

change in wavelength = …………………………………………………….. m 

(ii) Calculate the wavelength of light that is received by an observer on the Earth. (1)

wavelength = …………………………………………………….. m 

(b) One of the pieces of evidence for the Big Bang theory is the red-shift of galaxies. 

Explain how the red-shift of galaxies supports the Big Bang theory. (3)

(Total for Question 8 = 7 marks) 

2022 Paper 2PR Q6

6 (a) State what is meant by the astronomical term galaxy. (1)

(b) Which of these is a large collection of billions of galaxies? 

A  a nebula 
B  a red giant 
C  the solar system 
D  the universe 

(c) Hydrogen is an element that can emit visible light waves. 

The table shows the wavelength of one of these waves when detected from a laboratory sample of hydrogen and when detected from the hydrogen in two different galaxies. 

The detected wavelengths from the galaxies are different from the detected wavelength from the laboratory sample because of the Doppler effect. 

(i) Galaxy A and galaxy B are both moving relative to Earth. 

Compare the motions of galaxy A and galaxy B relative to Earth. (3)

(ii) Use data from the table to calculate the speed of galaxy B relative to Earth. (4)

[speed of light, c = 3.0 × 10⁸ m/s]

speed = ……………………………………….. m/s 

(Total for Question 6 = 9 marks)