Question

obtain mathematical expeession for the heat generated in a metallic conductor bt electric current(joules law)​

Answer 1

P  = VI  

                  H = P × t = Vlt

But             V = IR (ohm's law)  

∴                H = I²Rt

Answer 2

Joules law -

Electric energy = Heat energy

E = H = VIt

As we know - V= IR

E = H = (IR)It

I2Rt

Thus Heat = I2Rt

hope it helps