# "Explain" questions — WJEC GCSE Physics (Wales)

> 75 questions · physics

## How to answer

WHAT + WHY. Every point paired with a because. Structure: X happens because Y. This causes Z because … Assessment Objective: AO2. Every "explain" answer on this spec is marked against exactly this pattern.

## Sample questions

1. [A scientist is monitoring a radioactive isotope used in medical imaging. After 6 hours the count rate has fallen from 80…](https://www.gradenine.co.uk/q/a-scientist-is-monitoring-a-radioactive-04ec707d)
2. [A radioactive source emits beta particles. Explain what a beta particle is and describe how beta emission changes the nu…](https://www.gradenine.co.uk/q/a-radioactive-source-emits-beta-particles-0a482e4d)
3. [A musician plucks a guitar string. The string vibrates and produces a sound wave that travels through the air to a liste…](https://www.gradenine.co.uk/q/a-musician-plucks-a-guitar-string-0c55cf75)
4. [Astronomers observe that light from distant galaxies is red-shifted. Explain what red-shift tells us about the universe,…](https://www.gradenine.co.uk/q/astronomers-observe-that-light-from-distant-0fc295de)
5. [Explain how the refraction of seismic waves as they travel through the Earth provides evidence for the internal structur…](https://www.gradenine.co.uk/q/explain-how-the-refraction-of-seismic-10c1a51e)
6. [A hospital disposes of radioactive waste from a medical procedure. The waste contains a radioactive isotope with a half-…](https://www.gradenine.co.uk/q/a-hospital-disposes-of-radioactive-waste-176c4a7c)
7. [A tumble dryer has a power-rating of 2.5 kW. Explain what is meant by the term power-rating and describe how the amount …](https://www.gradenine.co.uk/q/a-tumble-dryer-has-a-power-rating-1d38ae47)
8. [A nuclear power station uses a radioactive fuel rod. After the fuel rod is removed from the reactor, it must be stored s…](https://www.gradenine.co.uk/q/a-nuclear-power-station-uses-a-1dcabaec)

## Related

- [WJEC GCSE Physics (Wales) revision notes](https://www.gradenine.co.uk/learn/wjec-gcse-physics-wales)
- [WJEC GCSE Physics (Wales) past papers](https://www.gradenine.co.uk/past-papers/wjec-gcse-physics-wales)
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