Power = (energy) divided by (time)
The circuit has to be closed so current flows.
Some of the forms of energy are: heat energy, mechanical energy, gravitational energy, electrical energy, sound energy, chemical energy, nuclear or atomic energy <span>and so on. Some examples of this are:
</span>Heat energy: the sun in our solar system. Mechanical energy: a moving car. Gravitational energy: a pen being held above a table. Electrical energy: lightning. Sound energy: musical Instruments. Chemical energy: batteries. Nuclear or atomic energy: the fusion reaction in the sun.
