1.
State what is meant by Stefan's law.
[1 mark]
- L = 4πr²σT⁴
JD SCIENCE
Astrophysics (option)
Indicative marking points. Award marks for equivalent scientific or mathematical wording. Do not issue this sheet with the student worksheet.
2.
State what is meant by Wien's law.
[1 mark]
- λ_max T = constant
3.
State what is meant by Hertzsprung–Russell diagram.
[1 mark]
- L against T (or spectral class)
4.
State what is meant by parallax.
[1 mark]
- p in arcseconds, d=1/p parsecs
5.
State what is meant by the Doppler effect for stars.
[1 mark]
- Δf/f = v/c
6.
State what is meant by Hubble's law.
[1 mark]
- v = H₀ d
7.
State what is meant by event horizon.
[1 mark]
- radius from which light cannot escape a black hole
8.
State what is meant by dark matter and dark energy (qualitative).
[1 mark]
- needed to explain rotation curves and acceleration of expansion
9.
State what is meant by Kepler's third law.
[1 mark]
- T² ∝ r³
10.
State what is meant by a standard candle.
[1 mark]
- object of known luminosity
11.
Amira is asked about Stefan's law in a AQA Physics paper.
(a) [2 marks]
- power of a black body
(b) [3 marks]
- hotter stars are much more luminous
12.
Amira is asked about Wien's law in a AQA Physics paper.
(a) [2 marks]
- colour linked to temperature
(b) [3 marks]
- blue stars are hotter
13.
Amira is asked about Hertzsprung–Russell diagram in a AQA Physics paper.
(a) [2 marks]
- main sequence, giants, white dwarfs
(b) [3 marks]
- evolution paths
14.
Amira is asked about parallax in a AQA Physics paper.
(a) [2 marks]
- nearest stars
(b) [3 marks]
- limit of the method
15.
Amira is asked about the Doppler effect for stars in a AQA Physics paper.
(a) [2 marks]
- red-shift recession
(b) [3 marks]
- binary stars
16.
Amira is asked about Hubble's law in a AQA Physics paper.
(a) [2 marks]
- age of the universe ~ 1/H₀
(b) [3 marks]
- expanding universe
17.
d=1/p. p=0.25″
[3 marks]
- Final answer: 4 pc
18.
v=H₀d. H₀=70 km s⁻¹ Mpc⁻¹, d=10 Mpc
[3 marks]
- Final answer: 700 km s⁻¹
19.
Wien: T if λmax=500 nm, constant=2.9×10⁻³
[3 marks]
- Final answer: 5800 K
20.
Age ~ 1/H₀. If H₀=2.2×10⁻¹⁸ s⁻¹
[3 marks]
- Final answer: 1.4 × 10¹⁰ years order
21.
Inverse square: flux 4 times smaller. Distance
[3 marks]
- Final answer: doubles
22.
T² ∝ r³. If r×4, T increases by
[3 marks]
- Final answer: 8 times
23.
Amira carries out a AQA-style required practical linked to astrophysics and the Newtonian world. This is a typical AQA required-practical style question.
(a) [2 marks]
- Independent: the independent variable for this topic
- Dependent: the measured outcome
(b) [2 marks]
- keep all other variables constant
- so the test is fair / only one variable is changed
(c) [2 marks]
- repeat and calculate a mean / use a tighter method
24.
Amira carries out collecting valid data for astrophysics and the Newtonian world. This is a typical AQA required-practical style question.
(a) [2 marks]
- Independent: a chosen factor
- Dependent: a quantitative measurement
(b) [2 marks]
- calibrated instrument
- so the test is fair / only one variable is changed
(c) [2 marks]
- systematic error from zero error
25.
Amira carries out drawing a graph for astrophysics and the Newtonian world. This is a typical AQA required-practical style question.
(a) [2 marks]
- Independent: x-variable
- Dependent: y-variable
(b) [2 marks]
- same scale / same apparatus
- so the test is fair / only one variable is changed
(c) [2 marks]
- not drawing a line of best fit through the trend
26.
Amira carries out evaluating a method about astrophysics and the Newtonian world. This is a typical AQA required-practical style question.
(a) [2 marks]
- Independent: method change
- Dependent: precision / accuracy
(b) [2 marks]
- same sample size
- so the test is fair / only one variable is changed
(c) [2 marks]
- too few repeats
27.
Compare Stefan's law with Wien's law.
[4 marks]
- L = 4πr²σT⁴
- λ_max T = constant
- give one linked difference
28.
Compare Wien's law with Hertzsprung–Russell diagram.
[4 marks]
- λ_max T = constant
- L against T (or spectral class)
- give one linked difference
29.
Compare Hertzsprung–Russell diagram with parallax.
[4 marks]
- L against T (or spectral class)
- p in arcseconds, d=1/p parsecs
- give one linked difference
30.
Compare parallax with the Doppler effect for stars.
[4 marks]
- p in arcseconds, d=1/p parsecs
- Δf/f = v/c
- give one linked difference
31.
Apply your knowledge of event horizon to this situation: Rₛ = 2GM/c²
[3 marks]
- Rₛ = 2GM/c²
32.
Apply your knowledge of dark matter and dark energy (qualitative) to this situation: not directly seen
[3 marks]
- not directly seen