Q25 of 330 Page 58

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) Here, V = 230V, I = 10amp

We know that, P = VI

P = 230X10

P = 2300watt = 2300 J/s

(b) The energy transferred in 1 minute. = P x t = 2300 J/s x 60s = 138000 J

Calculate the power used in the 2 Ω resistor in each of the following circuits:

(i) a 6V battery in series with 1 Ω and 2 Ω resistors.

(ii) a 4 V battery in parallel with 12 Ω and 2Ω resistors.

Two lamps, one rated 40 W at 220 V and the other 60 W and 220 V, are connected in parallel to the electric supply at 220 V.

(a) Draw a circuit diagram to show the connections.

(b) Calculate the total energy consumed by the two lamps together when they operate for one hour.

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?

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

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.