Q20 of 33 Page 158

Find the energy in kWh consumed in 10 hours by four devices of power 500 W each.

Given,

Power of one device = 500 W


Power of four devices = 500 × 4


= 2000 W


= kW


= 2 kW


Time = 10 h


We know that,


Power =


2 kW =


Energy consumed = 2 × 10


= 20 kWh


More from this chapter

All 33 →
17

Calculate the work required to be done to stop a car of 1500 kg moving at a velocity of 60 km/h?

 18

In each of the following a Force F is acting on an object of mass m.



The direction of displacement is from west to east shown by the longer arrow. Observe the diagrams carefully and state whether the work done by the force is negative, positive or zero.

 19

Soni says that the acceleration in an object could be zero even when several forces are acting on it. Do you agree with her? Why?

 21

A freely falling object eventually stops on reaching the ground. What happens to its kinetic energy?