Physics · Oct / Nov 2023 · Paper 12 · Question 22

Cotton wool is a good thermal insulator. It consists of many threads of cotton which are tangled together to make a material which can easily be pulled apart or compressed. The diagram shows the structure of cotton wool. Why is cotton wool a good thermal insulator?

1. AEach thread is very thin.
2. BIt has a large surface area because it is made of many threads.
3. CIt has a low density because of the trapped air.
4. DIt traps air and prevents convection.

As printed in the paper