Question

An ideal black body at room temperature is thrown into a furnace. It is observed that

• A. Initially it is the darkest body and at later times the brightest
• B. It is the darkest body at all times
• C. It cannot be distinguished at all times
• D. Initially it is the darkest body and at later times it cannot be distinguished

Answer 1

Answer: (A)

Initially black body absorbs all the radiant energy incident on it, so it is the darkest one. Black body radiates maximum energy if all other condition are same. So when the temperature of the black body becomes equal to the temperature of furnace it will be brightest of all.