The SI unit of power is the watt. Which of the following units are equivalent to the watt?

A) V∙AB) J/CC) C/sD) V/sE) A/s

The right option is (A) V. A

Explanation:

Power: This is the rate at which work is done. Or it is the produce of force and velocity. The S. I unit of power is Watt (W). Other units include Horse power (hp), foot-pound per minutes, etc.

Generally, power can be represented as,

Power = Energy/time

P = W/t ... Equation 1

Where p = power, w = Work or energy, t = time in seconds.

Electrical energy: This is the product of potential difference and the quantity of charge.

∴ W = VQ ... Equation 2

Where V = potential difference, Q = quantity of charge and W = Energy or Work done.

Also Q = It ... Equation 3.

where I = current in ampere, t = time in seconds

Substituting equation 3 into equation 3

W = VIt ... Equation 4.

Also substituting Equation 4 into Equation 1

P = VIt/t = VI = voltage (V) * Current (A)

Therefore the equivalent unit of power is

P = V. A.

The right option is (A) V. A