Question

Why are solar cooker painted black from inside

Answer 1

because black absorbs more heat

Answer 2

As solar cooker works on the principle of heating of the cooking vessel with the help of solar energy, i.e. , sunlight. So, for heating of vessel the energy absorption rate should be maximum and it can happen only if the color of the vessel will be black. Because, black is the only color that absorb all the visible spectrum wavelenth light. So, black color is highly preferable for solar cooker.