Question

An electric iron of resistance 20 Ω takes a current of 5 A. Calculate the heat developed in 30 s.

Answer 1

The amount of heat (H) produced is given by the joule’s law of heating as

Where,

Current, I = 5 A

Time, t = 30 s

Voltage, V = Current × Resistance = 5 × 20 = 100 V

Therefore, the amount of heat developed in the electric iron is.