Question

Give the construction of the solar cooker.

Answer 1

Hint: Solar cooker works on the principle of harvesting the sunlight. Solar energy which is obtained from the sun rays is used to cook the food. The construction of a solar cooker is theoretically simple. It is designed in such a way the heat produced from the sun rays is effectively utilized.

Complete step by step answer:
In order to describe the construction of solar cooker let us refer the diagram below

The solar cooker basically works on the principles of reflection, absorption, retention and greenhouse effect.
The sunlight which falls on the reflector i.e mirror gets reflected into the inner metal box. The inner metal box is coated in black color. This is done because black is a good absorber and it absorbs more heat. In between the inner metal box and outer wooden box, there is an insulator because heat should not escape outside. The reflected rays pass through the glass lid and enter the inner metal box. Since the metal box is coated black, it absorbs the heat from the reflected rays and temperature will raise nearly to 100 degree centigrade. We place the cooking box in the inner metallic box and that cooking box is coated black because it absorbs more heat. The heat can't escape out because the glass lid won’t allow and it radiates the heat back to the box. In this way first reflection happens from the reflector and then absorption happens in the metallic box and heat is retained due to black coating and due to radiation from glass lid greenhouse effect happens.

Hence this is the construction and working of the solar cooker.

Note:
The mirrors used as the reflectors are plain mirrors and we use concave mirrors too. The rays are assumed to be coming from the infinite distance and they will converge at the focus exactly. The cooking pot is kept at the focus so that the food will get cooked. In this way the entire intensity is concentrated at one point to get maximum heating effect.