Question

Look at the circuit. (a) What does the zigzag component R represent? (b) What will you observe if you touch R (carefully) a few minutes after the switch is closed? (c) Name one appliance that uses such a component.

An electric room heater of 2000 W is used for 3 hours every day for 30 days. Electrical energy in units = (power in watts × time in hours) ÷ 1000. If one unit costs ₹6, how much does it cost (in ₹) to run the heater for these 30 days?

A school had 20 incandescent bulbs of 60 W each in its classrooms. The principal replaced all of them with 20 LED lamps of 9 W each, which give about the same light. The lights are used for 6 hours a day. Energy in units = (power in watts × time in hours) ÷ 1000.