Power Energy Time Calculator

Power Energy Time Calculator


Power
Energy
Time

Definition

Power is the amount of energy consumed per unit time. In other words, power is the rate of doing work. Power is a scalar quantity which has no direction. Electric power is usually produced by electric generators, but can also be supplied by sources such as electric batteries.

Appliances used for heating have a much higher rating than those used to produce light or sound.

The amount of energy transferred from the mains appliance depends on the power rating of the appliance and the time for which it is switched on.

Formula

Formula used for Electric Power calculation is:

Power(Watt)[P] = Energy(J)[E]    /   Time taken(sec)[T]

Energy[E] = Power[P] * Time taken[T]

Example:

1. Find the electric power of an electrical circuit that consumes 10 joules for 2 seconds.

Sol. :

P = E / T

P = 10(J) / 2(sec)

P = 5 W

Power is 5 watts

2. When doing a chin-up, a Mary lifts her 42 kg body a distance of 0.25 m in 2 sec. What is the power delivered by the Mary’s biceps?

Sol. :

Force = mass * acc. due to gravity

F = 42(kg) * 9.8(m/s²)

F = 411.6 Nm/s²

Work = Force * distance

W = F * d

W = 411.6(N) * 0.250(m)

W = 102.9 J

Power = Work Done / Time taken

P = 102.9(J) / 2 (sec)

P = 51.45 W

Power is 51.45 watts

Units

The standard unit of measurement for Electric Power is Watt i.e. (W)

Below is the conversion chart of various other units of Power