Physics Circle home Student Login

Home›Chapters›Alternating Current PYQs›Series LCR Circuit›Question 58

JEE Main 2014 (9 Apr, Shift 1) · Series LCR Circuit

Series LCR Circuit question from JEE Main 2014 (9 Apr, Shift 1)

Q58JEE Main 2014 · 9 APR · SHIFT 1Medium

Series LCR Circuit

When the rms voltages VL, VC and VR are measured respectively across the inductor L, the capacitor C and the resistor R in a series LCR circuit connected to an AC source, it is found that the ratio VL: VC: VR = 1: 2: 3. If the rms voltage of the AC source is 100 V, then VR is close to:

Show answer and solution

Answer: (c)

  1. Let VL=xV_L = x, VC=2xV_C = 2x, VR=3xV_R = 3x.
  2. 1002=(3x)2+(x−2x)2=10x2⇒x=1010≈31.6100^2 = (3x)^2 + (x - 2x)^2 = 10x^2 \Rightarrow x = 10\sqrt{10} \approx 31.6 V
  3. VR=3x≈95V_R = 3x \approx 95 V, closest to 90 V.
  4. So the answer is (c) 90 V.
Report a mistake

More questions on Series LCR Circuit