A black body of temperature T is inside the chamber of  $T_0$  temperature initially. Sun rays are allowed to fall from a hole in the top of the chamber. If the temperatures of black body (T) and chamber  $\left(T_0\right)$   remain constant, then

Since the sun rays fall on the black body, it will absorb radiations and since its temperature is constant, it will emit radiations. So, Black body is absorbing more energy due to radiation coming from the sun.
The temperature will remain same only when energy emitted is equal to energy absorbed. So, the black body is rediating more energy now.