Radiation of a Spherical Body Inside a Black Body

[erisedk]

Homework Statement

A spherical body of area A and emissivity 0.6 is kept inside a perfectly black body. Total heat radiated by the body at temperature T is
(A) 0.4σAT⁴
(B) 0.8σAT⁴
(C) 0.6σAT⁴
(D) 1.0σAT⁴

Homework Equations

Stefan-Boltzmann's Law: P = AεσT⁴

The Attempt at a Solution

If it wasn't inside the black body, the answer would be (C). But it is inside one and I don't know what to do about it. Wouldn't the black body just absorb all the power radiated? We also don't know what temperature the black body is. And the question asks for total heat radiated, not power which is confusing because the answers will have dimensions of power, unless they've just omitted saying total heat per second. Honestly, I've always been a bit confused with emissivity and absorptivity. Please help.

 

[haruspex]

I'm as puzzled by the question as you are. Yes, clearly they mean rate of heat emission. I do not interpret total heat as net heat, so do not see how the black body affects it. Maybe that is the point of the question, that it is not affected. If it means the net heat then indeed you would need to know the temperature of the black body.

 

[erisedk]

The answer is D, if it helps. Otherwise, it seems like a pretty weird question, so I guess I'll skip it.