The SI unit of power is:

Solution

Physics sir · 3 steps

Power is how fast work gets done, so its unit is joules per second, which we call the watt.

1. What power means. Power is the rate of doing work, that is, work done divided by the time taken.

   P = W/t ⇒ 1 W = 1 J s⁻¹

2. Check the others. The joule is the unit of work or energy, the newton is the unit of force, and the pascal is the unit of pressure (1 Pa = 1 N m⁻²). None of them carries the per-second that power needs.
3. So. The SI unit of power is the watt, option (b).

The idea to keep. Power always has energy divided by time inside it. If a unit has no per second hidden in it, it cannot be a unit of power.

Answer from the NTA final answer key. Solution by PrepWiser.