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

Options

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

A

Explanation

(a) According to Krichoff's law, good absorbers are
good emitters as well.
At high temperature (in the furnace) since it absorbs
more energy, it emits more radiations as well and hence
is the brightest.