Question

Describe an experiment to show that a blackened surface is a better emitter of heat than a polished surface.

Answer 1

Take two sheets of tin plates, one blackened and the other is polished brightly. Fix some drawing pins on the outer side of both sheets using wax. Fix these plates vertically at a very short distance apart. Place a Bunsen burner midway between them. When you light the burner you will observe that the pins from the black painted sheet start dropping while the pins on the polished surface remain in the same position for a much longer time.
Thus, we can conclude that the black surface is a better absorber of heat than the polished one.