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# Power Formula

We all know that Energy is the capacity to do work. The Energy consumed to do work in unit time is called Power. It is denoted by P.
Power Formula is given by,
or

Where,
E = Energy Consumed to do work
W = Work done and
t = Time taken.

In any electrical circuit, the power is calculated using the 3 formulas

In terms of Voltage and current it is given as

In terms of current and resistance it is given as

In terms of voltage and resistance it is given as

Where,
V = voltage applied across the two ends,
I = Current flowing in the circuit and
R = Resistance.

Power formula is used to calculate the Power, Voltage, current or resistance in any electrical circuit. It is expressed in watts.

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## Power Problems

Below are some solved problems on Power which help understand these formulas.

### Solved Examples

Question 1: An electric machine uses 300 J of energy to do work in 10s. How much power does it uses?
Solution:

Given: Work done = W = 300 J,
Time taken t = 10 s.
Power used by it is given by P = $\frac{W}{t}$
= $\frac{300 J}{10 s}$
= 30 Watts.

Question 2: John is having mass 60 kg runs up to 12m high in 40 seconds. Calculate his power.
Solution:

Given: mass m = 60 kg,
Height h = 12 m,
time taken t = 40 seconds.
Power is given by P = $\frac{Work\ done}{time\ taken}$
= $\frac{mgh}{t}$
= $\frac{60 \times 9.8 \times 12}{40}$
= 588 Watts.

 More topics in Power Formula Horsepower Formula
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