an increase in the size of the copper particles a decrease in the mass of the copper particles an increase in the motion of the copper particles a decrease in the distance between the copper particles
I gave my students this multiple choice question: In a copper wire, a temperature increase is the result of which of the following?

Only one answer is correct among these 4 choices:
- an increase in the size of the copper particles
- a decrease in the mass of the copper particles
- an increase in the motion of the copper particles
- a decrease in the distance between the copper particles

Could you tell me which one is correct?

an increase in the motion of the copper particles