Two heating coils, one rated 100 W, 220 V and the other rated 300 W, 220 V, are connected in series across a 220 V supply. What is the total power consumed by the series combination?

Step-by-step solution

The resistance of a heating coil is given by R = V^2 P . For the first coil: R₁ = 220^2 100 , For the second coil: R₂ = 220^2 300 , When connected in series, the equivalent resistance is R_ eq = R₁ + R₂ . R_ eq = 220^2 100 + 220^2 300 = 220^2 ( 1 100 + 1 300 ) = 220^2 ( 3 + 1 300 ) = 220^2 ( 4 300 ) , The total power consumed by the series combination across the 220 V supply is: P_ total = V^2 R_ eq = 220^2 220^2 ( 4 300 ) = 300 4 = 75 W. Alternatively, for two appliances in series across their rated voltage, the e