At which temperature are the particles in a pencil moving faster: 20°C or 50°C?

Will you chech and finish these for me, because i am stumped with them.

Which is not a characteristic of a heat pump? a. it is used in air conditioners. b. it uses a refrigerant. c. it requires no work. d. it reverses the normal flow of thermal energy.

Which feature of a heating curve indicates a change ofn state