Q27 of 330 Page 58

What is the maximum power in kilowatts of the appliance that can be connected safely to a 13 A; 230 V mains socket?

Here I = 13amp, V = 230V

As we know that

Power = VI

= 230 x 13

= 2990W

P = 2.99kW

An electric kettle connected to the 230 V mains supply draws a current of 10 A. Calculate:

(a) the power of the kettle.

(b) the energy transferred in 1 minute.

A 2 kW heater, a 200 W TV and three 100 W lamps are all switched on from 6 p.m. to 10 p.m. What is the total cost at Rs. 5.50 per kWh?

An electric fan runs from the 230 V mains. The current flowing through it is 0.4 A. At what rate is electrical energy transferred by the fan?

What is meant by “electric power”? Write the formula for electric power in terms of potential difference and current.