Question

Name the physical quantity that gives the rate at which energy is transferred,

Give the mathematical expression for the same.

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Answer 1

Power is the physical quantity that gives the rate at which energy is transferred.

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Initially we can define power as :-

Power of machine can is the rate of work done by the machine.

∴ Power = Work/Time

But since, we know that work and energy are interconvertible, thus :-

∴ Power = Energy/Time

Thus, we can also define power as 'the rate of energy tranferred'.

Some basic knowledge about 'Power' :-

❒ It is a scalar quantity.

❒ S.I. unit of power is Watt (W)

 => 1 kW = 1000 W

 => 1 MW = 10⁶ W

❒ Another unit of power is

Horse Power (HP)

 => 1 HP = 746 W

❒  P = W/t

Also, we know that , W = F × s

Thus :-

=> P = F × s/t

=> P = F × v

This is power in terms of force and velocity.