Question

An electric lamp is marked 100W, 220 V. It is used for 4 hrs daily. Calculate: (i) current passing through it (ii) Bill generated for a week if each unit is rated at Rs.4 (show the steps too)

Answer 1

Answer:

Electric Lamp,

Power = 100W

Potential Difference = 220V

∴ Power = Potential Difference*Current

= 100 = 220*Current

= 0.45 A = Current

Unit consumed for a day = (wattage*hours)/1000

= (100*4)/1000 kWh

= 0.4 kWh

Unit consumed for a week = (0.4*7) kWh

= 2.8 kWh

If 1 kWh is rated Rs. 4, 2.8 kWh will be rated as = Rs. (2.8*4)

= Rs. 11.2

Hope this helps.