With the help of a diagram, explain the principle of a device which changes a low voltage into a high voltage but does not violate the law of conservation of energy. Give any one reason why the device may not be 100% efficient.

The transformer is a device used to convert low voltage to high voltage and vice versa without loss in energy.

A transformer is a static device which transforms electric energy from one circuit to another without any direct electrical connection and with the help of mutual induction between two coils.

Working principle: it works on the principle of mutual induction of two coils or Faraday Law’s Of Electromagnetic induction. When the current in the primary coil is changed the flux linked to the secondary coil also changes. Hence an EMF is induced in the secondary coil due to Faraday law’s of electromagnetic induction.

A transformer is not 100% efficient as all the electrical energy in the primary coil is not transferred to the secondary coil. Some of it is lost due to resistance in the winding and also due to magnetic effects such as core loss or iron loss.