Question

In which of the following cases more electrical energy is consumed per hour ?

(i) A current of 1 ampere passed through a resistance of 300 ohms.

(ii) A current of 2 amperes passed through a resistance of 100 ohms.

Answer 1

(A) I = 1 A ; R = 300 OHM

SO, P =R X I${}^2$

P= 300 X 1= 300 W = 300/1000 = 0.3 kW

SO, ELECRICAL ENERGY= PX t = 0.3 X 1= 0.3 kWH

(B) I= 2A ; R= 100 OHM

SO, P= R X I${}^2$

P= 100 X 4 = 400 W = 400/1000 = 0.4 kW

SO, ELECTRICAL ENERGY = 0.4 kW X 1 = 0.4 kWH