Question

A lamp consumes 1000 J of electrical energy in 10 s. What is its power?

NCERT Class IX
Sciences - Main Course Book

Chapter 11. Work and Energy

Answer 1

given that , 
   work done = 1000 J
   time taken = 10 sec.
   Power = ?
              = w/t 
              = 1000/10
               = 100w

Answer 2

Given that,

Energy consumed by the lamp, E = 1000 J

Time, t = 10 s

To find,

The power of the lamp.

Solution,

Power is defined as the work done divided by time. It can be given by the formula as follows :

$P=\dfrac{W}{t}\\\\P=\dfrac{1000\ J}{10\ s}\\\\P=100\ W$

So, the power of the lamp is 100 watts.