(a) What is meant by "electric power"? Write the formula for electric power in terms of potential difference and current.
(b) The diagram below shows a circuit containing a lamp L, a voltmeter and an ammeter. The voltmeter reading is 3V and the ammeter reading is 0.5A.

(i) What is the resistance of the lamp?
(ii) What is the power of the lamp?
(c) Define kilowatt-hour. How many joules are there in one kilowatt-hour?
(d) Calculate the cost of operating a heater of 500 W for 20 hours at the rate of Rs 3.90 per unit.

Answer

(b) (i) `6Omega` (ii) 1.5 W (d) Rs 39.00