Question

Two students made box-type solar cookers separately. They both painted the insulated box with black colour from inside, the cooking pots were painted black from outside, and a plane mirror reflector was also attached. One of the students covered the solar cooker box with a transparent glass sheet but the other student covered the solar cooker box with a transparent plastic sheet. Which of the two solar cookers will be more efficient and why?

Answer 1

The solar cooker with a transparent glass sheet will be more efficient because light rays after passing through glass sheet will get absorbed by the black walls of the box. The light will trap inside the box and the temperature will rise. The glass sheet will also prevent the radiation of the heat outside, so the temperature inside the box would be sufficient to cook the food. Whereas, in a solar cooker with a transparent plastic sheet, the heat will radiate outside and the temperature inside the box will never maintain to cook the food properly.