Question

An electric iron is connected to the mains power supply of 220 V. When the electric iron is

adjusted at 'minimum heating' it consumes a power of 360 W but at 'maximum heating' it takes a

power of 840 W. Calculate the current and resistance in each case.​

Answer 1

Answer:

Given: V = 220V, Pmin = 360W, Pmax = 840W

For minimum heating case:

We know that

Pmin = VI

360 = 220 X I

I = 1.63 amp

R = V/I

R = 220/1.63

R = 134.96ohms

For maximum heating case:

We know that

Pmax = VI

840 = 220 X I

I = 3.81 amp

R = V/I

R = 220/3.81

R = 57.74 ohms