Question

A lamp consumes 1500 J of electrical energy in 30 sec, what is its power?

Answer 1

Answer:

Power = Work/Time

Work done= Energy consumed by the lamp = 1000 J

Time = 10 s

Power= 1000/10= 100 Js-1=100 W

Answer 2

Given:

A lamp consumes 1500 J of electrical energy in 30 sec.

To find:

Power delivered by the lamp ?

Calculation:

Power is defined as the instantaneous rate of doing work.

In other words, power can be calculated from the ratio of work done and time taken to do the work.

$\rm\therefore \: power = \dfrac{work}{time}$

$\rm\implies \: power = \dfrac{1500}{30}$

$\rm\implies \: power = 50 \: watt$

So, power delivered by the lamp is 50 watt.