Question

An ekectric lamp is marked 100W,200V. It is used for 5 hours daily. Calculate 1. its resistance while glowing. 2. energy consumed in kWh per day

Answer 1

(1) _ 200×200÷100
=400 ohms (sinceR=square of voltage ÷power)
(2) energy consumed is=100w×5hour=500wh
500wh÷1000
=0.5kwh