Consider two identical copper spheres A and B. One is placed over a thermally insulating plate, while the other hangs from an insulating thread.
Equal amounts of heat are given to the two spheres and temperatures are recorded, then
(a) TA = TB
(b) TB < TA
(c) TB > TA
(d) cannot be concluded
Correct option is (c) TB > TA
Part of heat given to A is used up in doing work (against) gravitational force. So, temperature of B will be slightly higher.