An ac source of 50 V (r.m.s value) is connected across a series R - C circuit. If the r.m.s voltage across the resistor is 40 V, then the r.m.s voltage across the capacitor is

Options

A. 10 V
B. 20 V
C. 30 V
D. 40 V

Answer

C

Explanation

`V = sqrt(V_(R)^(2) + V_(C)^(2)) rArr V_(C) = sqrt(V^(2) - V_(R)^(2)) = sqrt((50)^(2) - (40)^(2))`
= 30 Volt