Practice E.5 Fusion and stars with authentic IB Physics exam questions for both SL and HL students. This question bank mirrors Paper 1A, 1B, 2 structure, covering key topics like mechanics, thermodynamics, and waves. Get instant solutions, detailed explanations, and build exam confidence with questions in the style of IB examiners.
Paper
Level
Question 1
SLPaper 2
Fusion reactions produce large amounts of energy.
1.[2]
Explain why the mass of a helium nucleus is less than the mass of 4 hydrogen nuclei.
2.[1]
Define the term “mass defect”.
3.[2]
A fusion reaction results in a mass defect of kg. Calculate the energy released.
Question 2
SLPaper 1A
Which of the following best describes a main sequence star?
Question 3
SLPaper 2
Nuclear fusion occurs in stars such as the Sun.
1.[1]
Define the term “nuclear fusion”.
2.[1]
State the condition necessary for fusion to occur.
3.[1]
Identify one element produced by fusion in the Sun.
4.[1]
State the role of fusion in the Sun.
Question 4
SLPaper 1A
Procyon A is a star with approximate radius and luminosity . If the surface temperature of the sun and Procyon are and respectively, what is ?
Question 5
SLPaper 1A
A star on the main sequence has surface temperature and radius . A second star has the same temperature but half the radius. What is the ratio of their luminosities?
Question 6
SLPaper 1A
Which unit is commonly used to express astronomical distances?
Question 7
SLPaper 2
This question is about stellar radiation and stellar types. Alnilam and Bellatrix are two stars in the constellation of Orion. The table gives information on each of these stars. L⊙ is the luminosity of the Sun and R⊙ is the radius of the Sun.
| Apparent magnitude | Absolute magnitude | Surface temperature | Luminosity | Radius | |
|---|---|---|---|---|---|
| Alnilam | +1.68 | -6.37 | 27000 K | 275000 L⊙ | 24 R⊙ |
| Bellatrix | +1.62 | -2.37 | 6400 L⊙ | 6 R⊙ |
1.[2]
Explain how Alnilam has a similar apparent magnitude to Bellatrix but a smaller absolute magnitude.
2.[2]
Calculate the surface temperature of the star Bellatrix.
3.[2]
Using a telescope based on Earth, an observer estimates the distance to Alnilam using the stellar parallax method. Describe the stellar parallax method.
4.[3]
Determine whether the stellar parallax method can be used to estimate the distance of Alnilam from Earth.
Question 8
SLPaper 2
This question is about determining the distance to a nearby star. Two photographs of the night sky are taken, one six months after the other. When the photographs are compared, one star appears to have shifted from position A to position B, relative to the other stars.
1.[1]
Outline why the star appears to have shifted from position A to position B.
2.[1]
The observed angular displacement of the star is θ and the diameter of the Earth's orbit is d. The distance from the Earth to the star is D. Draw a diagram showing d, D and θ.
3.[2]
Explain the relationship between d, D and θ.
4.[1]
One consistent set of units for D and θ are parsecs and arc-seconds. State one other consistent set of units for this pair of quantities.
5.[1]
Suggest whether the distance from Earth to this star can be determined using spectroscopic parallax.
Question 9
SL & HLPaper 1A
What minimum temperature is typically required for hydrogen fusion to occur in stars?
Question 10
SL & HLPaper 1A
A star’s radius is most directly related to which two properties?