electric iron consumes energy at a rate of 840 W when heating iaAnat t

1.	electric iron consumes energy at a rate of 840 W when heating iaAnat the maximum rate and 360 W when the heating is at the minimumThe voltage is 220 V. What are the current and the resistance in eachase
Answer» At maximum heating, power is P = 840 W We know, P = V^2/R => R = V^2/P Working voltage is 220 V So, resistance at maximum heating is = 220^2/840 = 57.6 Ω The current is found as, I = P/V (since, P = VI) So, current at maximum heating is = 840/220 = 3.8 A At minimum heating, power is = 360 W The resistance at minimum heating will be = 220^2/360 = 134.4 Ω The current at minimum heating will be = 360/220 = 1.6 A

electric iron consumes energy at a rate of 840 W when heating iaAnat the maximum rate and 360 W when the heating is at the minimumThe voltage is 220 V. What are the current and the resistance in eachase

Answer»

At maximum heating, power is P = 840 W

We know, P = V^2/R

=> R = V^2/P

Working voltage is 220 V

So, resistance at maximum heating is = 220^2/840 = 57.6 Ω

The current is found as, I = P/V (since, P = VI)

So, current at maximum heating is = 840/220 = 3.8 A

At minimum heating, power is = 360 W

The resistance at minimum heating will be = 220^2/360 = 134.4 Ω

The current at minimum heating will be = 360/220 = 1.6 A