Energy can neither be generated nor destroyed. It can only be converted from one form to another.
mirrors are used to reflect sunlight on the the cooker thus more heat.
According to the law of conservation of energy, energy can neither be generated nor can it be destroyed. It can only be converted from one form to another. For example, when a ball hits the ground, some part of the potential energy of the ball is converted to its kinetic energy whereas the rest is dissipated as heat and sound to the environment.