Question

In a dark room with ambient temperature $T_0$, a black body is kept at a temperature T. Keeping the temperature of the black body constant (at T), sun rays are allowed to fall on the black body through a hole in the roof of the dark room. Assuming that there is no change in the ambient temperature of the room, which of the following statement(s) is/are correct?

• A. The quantity of radiation absorbed by the black body in unit time will increase
• B. Since emissivity $=$ absorptivity, hence the quantity of radiation emitted by black body in unit time will increase
• C. Black body radiates more energy in unit time in the visible spectrum
• D. The reflected energy in unit time by the black body remains same

Answer 1

The correct option is D The reflected energy in unit time by the black body remains same

The reflected energy in unit tune remains same because for a black body reflected energy is always $=0$. Black body radiated energy not reflects energy