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Practice each question, then open the answer or worked solution.
What is power?
Power is defined as the rate of doing work or the rate of transfer of energy. If an agent does a work W in time t, then power is given by:
P = W/T
It is expressed in watt (W).
Define 1 watt of power.
A body is claimed to possess power of one watt if it works at the speed of 1 joule in 1 s.
That is,
One W = 1 J/1 S
A lamp consumes 1000 J of electrical energy in 10 s. What is its power?
Power = Work/Time
P = W/T
Time = 10 s
Work done = Energy consumed by the lamp = 1000 J
Power = 1000/10 = 100 Js-1 =100 W
Hence, the power of the lamp is 100 W
Define average power.
Average power is defined as the ratio of total work done by the body to the total time taken by the body.
