A star is 6 light-years6\text{ light-years}6 light-years away from Earth. A space probe is sent to this star and back again at a constant speed of 0.2% of the speed of light.
What is the total time taken for this round-trip journey?
600 years600\text{ years}600 years
3 000 years3\,000\text{ years}3000 years
6 000 years6\,000\text{ years}6000 years
12 000 years12\,000\text{ years}12000 years
25 exam-style questions on CIE IGCSE Physics 6.2.2a Galaxies and astronomical distances. Each one has a worked solution and a mark scheme showing where the marks go.