All Problems

Electric Oscillations

Problem 4.139

A circuit consisting of a capacitor and a coil in series is connected to the mains. Varying the capacitance of the capacitor, the heat power generated in the coil was increased n=1.7n=1.7 times. How much (in per cent) was the value of cos φ\varphi changed in the process?

Reveal Answer
 Increased by n130% . \text { Increased by } \sqrt{n}-1 \approx 30 \% \text { . }