Question

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

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

Answer 1

Answer: (C)

Black body radiates maximum number of wavelength and maximum energy if all other conditions (e.g., temperature, surface area etc.) are same. So, when the temperature of black body becomes equal to the temperature of the furnace, the black body will radiate maximum energy and it will be brightest of all. Initially it will absorb all the radiant energy incident on it. So, it is the darkest one