AQA A-LEVEL
ASTROPHYSICS 2025
(PAPER 3)
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This Exam contains: AQA A-Level Astrophysics
✓ 2025 (Paper 3)
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,Question 1
What object is thought to exist at the centre of most galaxies.
Correct Answer
A supermassive black hole, whose mass may be several million times the mass of the Sun.
Question 2
Describe what produces a gamma ray burst and explain why it could be hazardous if incident on Earth.
Correct Answer
A gamma ray burst is produced when a supergiant star collapses to form a neutron star or a black hole.
A gamma ray burst is highly collimated and could kill cells or damage DNA if incident on Earth.
Question 3
Explain what is meant by the Rayleigh Criterion
Correct Answer
The Rayleigh criterion identifies the minimum subtended angle between two objects whose images can be
resolved. (The minimum angular resolution).
The minimum angle is when the central maximum of the diffraction pattern of one object coincides with the first
minimum of the second object.
Question 4
Sketch or describe a diagram to show the diffraction pattern produced by a circular aperture. Label the centre of the
diffraction pattern, the Airy disc and the first minimum.
Sketch or describe a graph to show how this pattern appears as graph of light intensity against angle
Correct Answer
Y13 textbook page 208.
Intensity graph same shape as Y12 textbook page 87.
Question 5
Describe how red shift provides evidence for the Big Bang theory
Correct Answer
The theory predicts that distant galaxies are all moving away from us and the further the galaxy the faster it
moves. Measurements of the red shift of distant galaxies suggest that recessional velocity is directly proportional
to distance to galaxy (Hubble's Law, v =Hd).
Trusted by thousands of students and professionals worldwide Page 2 of 16
, Question 6
Describe advantages of reflecting telescopes over refracting telescopes.
Correct Answer
Mirrors do not suffer from chromatic aberration
Mirrors can be larger and therefore have greater collecting powers (brighter images)
Mirrors can be larger and therefore have smaller minimum angular resolution (clearer images)
Parabolic mirrors do not suffer from spherical aberration
Question 7
What class of star has most prominent visible hydrogen absorption lines + why?
What are these lines called?
Correct Answer
A class stars as they have a temperature sufficient to excite electrons to the n = 2 state, and a temperature lower
than 11 000 K and so not high enough to cause ionisation.
Visible hydrogen absorption lines are called Balmer lines.
Question 8
What is meant by the brightness (of a star) is subjective?
Correct Answer
How bright a star appears to be depends on both the distance from observer to the star, and the power of the star
at visible wavelengths.
Question 9
Describe how the transit method can be used to detect exoplanets.
Sketch or describe a typical transit light curve.
What limitations are there to this method?
Correct Answer
The apparent magnitude of a star is measured over a long period of time. When a planet passes in front of the
star some of the light from the star is absorbed and so there is a periodic dimming in the apparent magnitude of
the star.
Y13 textbook page 252.
Limitations are that other processes such as sun spots or variations in output from star can cause a periodic
dimming.
Trusted by thousands of students and professionals worldwide Page 3 of 16
ASTROPHYSICS 2025
(PAPER 3)
60+ (Latest 2025-2026 Edition) 100%
Verified Q&A + Answer Key Solutions
100% Guarantee Pass
This Exam contains: AQA A-Level Astrophysics
✓ 2025 (Paper 3)
✓ 100% Accurate Questions and Answers
✓ 100% Guarantee Pass - Verified by Experts
✓ Each Question Includes The Correct Answer
✓ Expert-Verified
Trusted by thousands of students and professionals worldwide Page 1 of 16
,Question 1
What object is thought to exist at the centre of most galaxies.
Correct Answer
A supermassive black hole, whose mass may be several million times the mass of the Sun.
Question 2
Describe what produces a gamma ray burst and explain why it could be hazardous if incident on Earth.
Correct Answer
A gamma ray burst is produced when a supergiant star collapses to form a neutron star or a black hole.
A gamma ray burst is highly collimated and could kill cells or damage DNA if incident on Earth.
Question 3
Explain what is meant by the Rayleigh Criterion
Correct Answer
The Rayleigh criterion identifies the minimum subtended angle between two objects whose images can be
resolved. (The minimum angular resolution).
The minimum angle is when the central maximum of the diffraction pattern of one object coincides with the first
minimum of the second object.
Question 4
Sketch or describe a diagram to show the diffraction pattern produced by a circular aperture. Label the centre of the
diffraction pattern, the Airy disc and the first minimum.
Sketch or describe a graph to show how this pattern appears as graph of light intensity against angle
Correct Answer
Y13 textbook page 208.
Intensity graph same shape as Y12 textbook page 87.
Question 5
Describe how red shift provides evidence for the Big Bang theory
Correct Answer
The theory predicts that distant galaxies are all moving away from us and the further the galaxy the faster it
moves. Measurements of the red shift of distant galaxies suggest that recessional velocity is directly proportional
to distance to galaxy (Hubble's Law, v =Hd).
Trusted by thousands of students and professionals worldwide Page 2 of 16
, Question 6
Describe advantages of reflecting telescopes over refracting telescopes.
Correct Answer
Mirrors do not suffer from chromatic aberration
Mirrors can be larger and therefore have greater collecting powers (brighter images)
Mirrors can be larger and therefore have smaller minimum angular resolution (clearer images)
Parabolic mirrors do not suffer from spherical aberration
Question 7
What class of star has most prominent visible hydrogen absorption lines + why?
What are these lines called?
Correct Answer
A class stars as they have a temperature sufficient to excite electrons to the n = 2 state, and a temperature lower
than 11 000 K and so not high enough to cause ionisation.
Visible hydrogen absorption lines are called Balmer lines.
Question 8
What is meant by the brightness (of a star) is subjective?
Correct Answer
How bright a star appears to be depends on both the distance from observer to the star, and the power of the star
at visible wavelengths.
Question 9
Describe how the transit method can be used to detect exoplanets.
Sketch or describe a typical transit light curve.
What limitations are there to this method?
Correct Answer
The apparent magnitude of a star is measured over a long period of time. When a planet passes in front of the
star some of the light from the star is absorbed and so there is a periodic dimming in the apparent magnitude of
the star.
Y13 textbook page 252.
Limitations are that other processes such as sun spots or variations in output from star can cause a periodic
dimming.
Trusted by thousands of students and professionals worldwide Page 3 of 16
