An electric kettle for use on a 230 V supply is rated at 3000 W. For safe working, the cable connected to it should be able to carry at least:
A. 2 A

B. 5 A

C. 10 A

D. 15 A

Power of a lamp is 60 W. Find the energy in joules consumed by it in 1s.

Show how would you join three resistors, each of resistance 9Ω so that the equivalent resistance of the combination is (i) 13.5 Ω, (ii) 6 Ω?

OR

(a) Write Joule’s law of heating.

(b) Two lamps, one rated 100 W; 220 V, and the other 60 W; 220 V, are connected in parallel to electric mains supply. Find the current drawn by two bulbs from the line, if the supply voltage is 220 V.

Three 2Ω resistors, A,B and C, are connected as shown in the figure. Each of them dissipates energy and can withstand a maximum power of 18 W without melting. Find the maximum current that can flow through the three resistors.

The electric power consumed by a device may be calculated by the using either of the two expressions P = I²R or P = V²/R. The first expression indicates that it is directly proportional to R whereas the second expression indicates inverse proportionality. How can the seemingly different dependence of P on R in these expressions be explained.

An electric lamp is marked 26 W, 220V. It is used for 10 hours daily. Calculate

energy consumed in kWh per day.