Which of the following is NOT a correct expression for electric power (P)?

Explanation:

Electric power can be written using these correct formulas:

• $P = V \times I$

• $P = I^2 R$

• $P = \dfrac{V^2}{R}$

These are derived using Ohm’s Law ($V = IR$).

Now check the given incorrect expression:

• $P = I \times R^2$

Using units:

• $I$ has unit ampere (A)

• $R$ has unit ohm (Ω)

So $I \times R^2$ gives units $A \cdot \Omega^2$, which is not equal to watt (W). Hence, it is incorrect.

Note:
The expression $P = \dfrac{R}{V^2}$ is also incorrect. The correct form is $P = \dfrac{V^2}{R}$.