Suppose a Current I flows through a circuit as shown in the figure. The voltage across the resistance is V . The P.D. is the work done to move a charge Q from one point to another point, between which the p.d. is applied.
W = QV
But, Q= I.t
∴ W = VIt
Another energy equation By Ohm’s Law:
V= I. R
Now, W = VIt
W = IR. It
∴ W = I2Rt
We can also write the energy equation in terms of voltage , resistance and time.
W = (V / R )2. Rt
∴ W = (V2t) / R
∴ W = Qv = VIt = I2Rt= (V2t) / R
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