CBSE Class 10 Answered

Why: The electrical energy gets converted to heat energy as a consequence of the Joul heating - process by which the passage of an electric current through a conductor releases heat.

 

It is now known that Joule heating is caused by interactions between the moving particles that form the current (usually, but not always, electrons) and the atomic ions that make up the body of the conductor. Charged particles in an electric circuit are accelerated by an electric field but give up some of their kinetic energy each time they collide with an ion. The increase in the kinetic or vibrational energy of the ions manifests itself as heat and a rise in the temperature of the conductor. Hence energy is transferred from the electrical power supply to the conductor and any materials with which it is in thermal contact.

 

The amount of heat generated is Q, 

 

because of the above relation. High resistance results in greater heat being produced, as Q is directly proportional to R.