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Home · IGCSE 0625 · Space physics · The Sun as a star · Practice
Core · Practice questions · The Sun as a star

Hydrogen into helium.

Six original Cambridge-style questions on the Sun: its size, what it is made of, and how fusion powers it.

Original questions All questions on this page are original work, written in the Cambridge IGCSE style. They are not from past papers. They test the same concepts and skills the syllabus rewards.
What the examiner wants

A medium star, fusing.

01
Recall
[2 marks]

State what type of object the Sun is, and its size compared with other stars.

  • The Sun is a star. ✓
  • It is a medium-sized star. ✓
02
Recall
[1 mark]

State the two elements the Sun is mostly made of.

  • Hydrogen and helium. ✓
03
Recall
[2 marks]

Name the process that releases energy in the Sun's core, and state what it turns into what.

  • Nuclear fusion. ✓
  • Hydrogen is fused into helium. ✓
04
Application
[1 mark]

State the main source of energy for the Solar System.

  • The Sun. ✓
05
Analysis
[2 marks]

A student writes that the Sun produces energy by burning. Explain why this is wrong.

  • Burning is a chemical reaction; the Sun's energy comes from nuclear fusion. ✓
  • Fusion releases far more energy, which is why the Sun can shine for billions of years. ✓
06
Application
[2 marks]

The stars seen at night are similar objects to the Sun. Explain why they look so much fainter.

  • They are stars like the Sun. ✓
  • They are vastly further away, so they appear much fainter. ✓

Mark this once you have attempted all six and checked your working. It records a Practiced badge on the topic and adds a one-time bonus. Revealing the solutions alone does not count.