Problem 4.142

A coil and an inductance-free resistance $R=25 \Omega$ are connected in parallel to the ac mains. Find the heat power generated in the coil provided a current $I=0.90 \mathrm{~A}$ is drawn from the mains. The coil and the resistance $R$ carry currents $I_{1}=0.50 \mathrm{~A}$ and $I_{2}=$ $=0.60$ A respectively.