Derive the expression for the heat produced due to a current 'I' flowing for a time interval 't' through a resistor 'R' having a potential difference 'V' across its ends. With which name is this relation known?

All materials offer resistance to the flow of current through them. So some external energy is required to make the current flow. This energy is provided by the battery. Some of this energy gets dissipated as heat energy, so the resistor becomes hot.

Work done in carrying a charge Q through a potential difference V is given as


Also, Q = I t


Using Ohm's law, V = I R


W = I2 Rt


This work done in carrying the charge through the wire appears as the heat produced.


i.e. H = V I t = I2 Rt.


this energy is dissipated as heat energy.


This law is called Joule law of heating effect.


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