# Define electric power. An electrical device of resistance R is connected across a source of voltage V and draws a current I. Derive an expression for power in terms of current and resistance. - Science

Define electric power. An electrical device of resistance R is connected across a source of voltage V and draws a current I. Derive an expression for power in terms of current and resistance.

#### Solution

Electric power is defined as the rate of consumption of energy or simply the rate of doing work.
i.e., power, P =(" work done"("W"))/("Time"("t")) ..............(i)

The work done by current (I) when it flows in a potential (V) for time (t) can be given by

W = VIt …………………. (ii)

⇒ Power, P = "VIt"/"t"="VI"

∴Electric power, P = VI

From Ohm's law, V=VI

Thus, electric power is given by, P = (IR)I = I2R

Is there an error in this question or solution?