question_answer

Explain why cooking utensils are often blackened at the bottom and polished at the top.

Answer:

                Black surfaces are good absorbers of heat radiations. The bottom of the cooking utensils is blackened so that it absorbs maximum heat radiations. Polished white surfaces are bad absorbers and hence bad emitters of heat radiations. By polishing the upper parts of the cooking utensils, the loss of heat by radiation is minimised.