During transformation of energy from one form to another it remains constant. This is known as Law of Conservation of Energy.
- Potential Energy of water stored in a dam changes into kinetic energy as water falls from a height.
- The kinetic energy of flowing water changes into kinetic energy of rotation of a turbine. The coil attached with the shaft of the turbine rotates in a magnetic field to convert kinetic energy of rotation of turbine into electrical energy.
- In our homes, electric bulbs or tube-lights convert electric energy into light energy.
- Electric pump (or motor) converts electrical energy into mechanical energy.
- Work done against friction is converted into heat.
- The sun transforms nuclear energy into heat and light energy (and also ultraviolet, infrared, and gamma energy).
- Solar cells convert light energy into electrical energy.
- An electric cell converts chemical energy into electrical energy.
- Nuclear energy generates a tremendous amount of thermal energy which can be converted into electrical energy at nuclear power plants.