Question

An electric bulb of resistance 200Ω draws a current of 1 Ampere. Calculate the power of the bulb the potential difference at its ends and the energy in kWh consumed burning it for 5h.

Answer 1

Power of the bulb,

P = l²R = (1)² x 200

⇒ P = 200 W

Energy consumed by bulb in 5h in burning 

= Power x Time 

= 200 x 5 

= 1000 Wh = 1 kWh