Question

Two identical objects A and B are at temperatures $T_A$ and $T_B$ respectively, Both objects are placed in a room with perfectly absorbing walls maintained at a temperature $T(T_A>T>T_B)$. The objects A and B attain the temperature T eventually. Select the correct statements from the following.

• A. A only emits radiation, while B only absorbs it until both attain the temperature T.
• B. A loses more heat by radiation than it absorbs, while B absorbs more radiation than it emits, until they attain the temperature T.
• C. Both A and B only absorb radiation, but do not emit it, until they attain the temperature T.
• D. Each object continues to emit and absorb radiation even after attaining the temperature T.

Answer 1

Answer: (B), (D)

The correct options are
B A loses more heat by radiation than it absorbs, while B absorbs more radiation than it emits, until they attain the temperature T.
D Each object continues to emit and absorb radiation even after attaining the temperature T.

Every object emit and obsorb the radiations simultaneously, if energy emitted is more than energy absorbed temperature falls and vice versa.

Why this question? Possible mistake- tendency to think that a body only emits radiation to lower temperature!