An electric iron consumes energy at a rate of 840 W when heating it at the maximum rate and 360 W when the heating it at the minimum. The applied voltage is 220 V. What is the value of current and the resistance in each case?

Explanation

We know that the power input is P=VI
Thus the current, `I = (P)/(V)`
When heating is at the maximum rate,
`I= (840W)/(220V)= 3.82A`
and the resistance of the electric iron is
`R= (V)/(I)= (220V)/(3.82A)= 57.59Omega`
When heating is at the minimum rate,
`I= (360W)/(220V)= 1.64A`
and the resistance of the electric iron is
`R= (V)/(I)= (220V)/(1.64A)= 134.15Omega`