Medium MCQ +4 / -1 PYQ · JEE Mains 2020

A LCR circuit behaves like a damped harmonic oscillator. Comparing it with a physical spring-mass damped oscillator having damping constant 'b', the correct equivalence would be:

  1. A L $\leftrightarrow$ k, C $\leftrightarrow$ b, R $\leftrightarrow$ m
  2. B L $\leftrightarrow$ m, C $\leftrightarrow$ k, R $\leftrightarrow$ b
  3. C L $\leftrightarrow$ m, C $\leftrightarrow$ ${1 \over k}$, R $\leftrightarrow$ b Correct answer
  4. D L $\leftrightarrow$ ${1 \over b}$, C $\leftrightarrow$ ${1 \over m}$, R $\leftrightarrow$ ${1 \over k}$

Solution

For spring mass damped oscillator <br><br>ma = - kx - bv <br><br>$\Rightarrow$ ma + kx + bv = 0 <br><br>$\Rightarrow$ $m{{{d^2}x} \over {d{t^2}}}$ + b${{dx} \over {dt}}$ + kx = 0 ....(1) <br><br>For LCR circuit <br><br>L${{di} \over {dt}}$ + iR + ${q \over C}$ = 0 <br><br>$\Rightarrow$ L${{{d^2}q} \over {d{t^2}}}$ + R${{dq} \over {dt}}$ + ${q \over C}$ = 0 .....(2) <br><br>Comparing (1) and (2), we get <br><br>L $\leftrightarrow$ m, C $\leftrightarrow$ ${1 \over k}$, R $\leftrightarrow$ b

About this question

Subject: Physics · Chapter: Alternating Current · Topic: AC Circuits: R, L, C

This question is part of PrepWiser's free JEE Main question bank. 115 more solved questions on Alternating Current are available — start with the harder ones if your accuracy is >70%.

Drill 25 more like these. Every day. Free.

PrepWiser turns these solved questions into a daily practice loop. Chapter-wise drills, full mocks, AI doubt chat. No auto-renew.

Start free →