Question

an electric lamp is marked 100w, 220 V it is used for 5 hours daily calculate (1)resistance, while glowing (2)energy consume in kwh per day

Answer 1

we know that
${v}^{2} \div r = p$
v= voltage r= resistance p = power
Put values in Formula and you will get R= 484 ohm.
Now energy consumption = Power * time i. e. 5*100= 0.5kwh.