Question

Unit of electric power may also be expressed as

• A. Volt ampere
• B. Kilowatt hour
• C. Watt second
• D. Joule second

Answer 1

The correct option is A

Volt ampere

Explanation for correct option:

Formula for the power is as follows.

$P=VI$

Where, Power is $P$, current is $I$ and the voltage difference is $V$.

Since unit of the current is Ampere, and the unit of the voltage is Volt, therefore

$P=\text{Volt×Ampere}$

Therefore the unit of the power is $\text{Volt Ampere}$.

Explanation for incorrect option:

1. Kilowatt hour is the unit of energy. It means the $1\text{kW}$ of power is available for $1\text{hr}$.
2. Watt second is the unit of the energy. It means the $1\text{W}$ of power is available for $1\text{second}$.
3. Joule second is neither the unit of energy nor the power.

Hence, option (A) is correct.