BIENT TEMPERATURE AND RADIATION EQUILIBRIUM BETWEEN TWO BODIES IN A VACUUM

[Amith2006]

Sir,
Two bodies one hot and other cold are kept in vacuum. What will happen to the temperature of hot body after sometime?
I think that the temperature of the hot body decreases due to radiation as it needs no medium. But the book answer says that it will remain constant. Which is correct?

 

[Astronuc]

I would expect the hot body to radiate heat and the colder body to absorbed radiated heat until they reach equilibrium with the environment.

Is there no information on the temperatures of the bodies and the surrounding vacuum.

Certainly there is no heat transfer via conduction or convection.

 

[Andrew Mason]

Sir,
Two bodies one hot and other cold are kept in vacuum. What will happen to the temperature of hot body after sometime?
I think that the temperature of the hot body decreases due to radiation as it needs no medium. But the book answer says that it will remain constant. Which is correct?

Your textbook seems to have an extraordinary number of wrong answers. What text are you using?

The question should state how the bodies achieved their temperatures. If, for example the hot one is hot because the sun is shining on it, so long as the sun keeps shining it will reach and keep an equilibrium temperature at which its rate of energy absorption equals its rate of emission.

AM