Question

Which of the following is not equal to watt?
1. Joule/sec
2. Ampere × volt
3. Ampere² × ohm
4. Ampere/volt

Answer 1

Correct Answer - Option 4 : Ampere/volt

CONCEPT:

• Power: It is defined as the rate of doing work.
  • The unit of power is a watt.

\(⇒ P=\frac{W}{t}\)

Where W = work, and t = time

EXPLANATION:

We know that the power is given as,

\(⇒ P=\frac{W}{t}\)     -----(1)

Where W (Joule) = work, and t (sec) = time

By equation 1 the unit of power is given as Joule/sec.

The electrical power is given as,

⇒ P = IV = I²R     -----(2)

Where I (Ampere) = current, V (volt) = Potential difference and R (ohm) = Resistance

By P = IV, the unit of power is Ampere × volt.

By P = I²R, the unit of power is Ampere² × ohm.

• By the above explanation, it is clear that the Ampere/volt cannot be the unit of power.
• Hence, option 4 is correct.