A: 1st statement --- true , 2nd statement --- true (2nd statement is the explanation of the 1st statement)
B: 1st statement --- true , 2nd statement --- true (2nd statement is not the explanation of the 1st statement)
C: 1st statement --- true , 2nd statement --- false
D: 1st statement --- false , 2nd statement --- true
1. During conduction, the net transfer of heat stops when both bodies attain the same temperature. The internal energy of the resulting bodies becomes the same.
2. Hot objects can emit infra-red radiation of higher intensity than cold objects. Infra-red radiation can travel through vacuum.
3. Heat energy may be transferred by infra-red radiation through vacuum. Infra-red is a kind of electromagnetic waves.
4. Convection can take place in liquid and gas only. Liquid and gas obtain free electrons as energy carries.
更新1:
Please explain for every questions. I will make you be the best answer if you explain in the best way. (please do not copy others' answer) Thank you!