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Home · IGCSE 0625 · Space physics · Redshift and the Big Bang · Practice
Core · Practice questions · Redshift and the Big Bang

Light from the edge.

Six original Cambridge-style questions on redshift, the expanding universe, and the Big Bang.

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

Further, faster, redder.

01
Recall
[2 marks]

State what is meant by redshift, and what it tells us about a galaxy.

  • The galaxy's light is shifted toward the red (longer wavelength) end of the spectrum. ✓
  • It tells us the galaxy is moving away from us. ✓
02
Recall
[2 marks]

State the link between how far away a galaxy is and how fast it moves away.

  • The further away a galaxy is, the faster it is moving away. ✓
  • So more distant galaxies have a greater redshift. ✓
03
Analysis
[2 marks]

Explain how redshift provides evidence that the universe is expanding.

  • Distant galaxies are all moving away from us. ✓
  • Galaxies moving apart in every direction means the universe is expanding. ✓
04
Application
[2 marks]

Galaxy P has a larger redshift than Galaxy Q. State which is further away and which is moving faster.

  • Galaxy P is further away. ✓
  • Galaxy P is moving away faster. ✓
05
Recall
[1 mark]

State the name of the theory that the expanding universe supports.

  • The Big Bang theory. ✓
06
Analysis
[2 marks]

A student thinks the redshift proves the Earth is at the centre of the universe. Explain why this is not correct.

  • Space itself is expanding, so every galaxy sees all the others moving away. ✓
  • An observer anywhere would see the same thing, so there is no special centre. ✓

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.