How much energy is consumed when a current of 5 amperes flows through the filament (or element) of a heater having resistance of 100 ohms for two hours? Express it in joules.

Here, current (I) = 5amp, Resistance(R) = 100 ohms and time = 2h

As we know that

Electric energy consumed = P x t = I²Rt

= 5² x 100 x 2

= 5000 Wh

= 5 kwh

We know that

1kwh = 3.6 x 10⁶ J

Therefore, 5kwh = 5 x 3.6 x 10⁶ J = 18 x 10⁶ J