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JEE Main 201212 MayOnline
Exam
JEE Main
Year
2012
Date
12 May
Mode
Online
Subject
Physics
Chapter
Alternating Current

JEE Main 2012 · 12 May · Online · Physics · Alternating Current

A resistance R and a capacitance C are connected in series to a...

A resistance RR and a capacitance CC are connected in series to a battery of negligible internal resistance through a key. The key is closed at t=t= 0 . If after tt sec the voltage across the capacitance was seven times the voltage across R\mathrm{R}, the value of t\mathrm{t} is

Options

  1. A3RCℓn23 R C \ell n 2
  2. B2RCℓn22 R C \ell n 2
  3. C2RCln⁡72 R C \ln 7
  4. D3RCℓn73 R C \ell n 7

Correct answer

A. 3RCℓn23 R C \ell n 2

Step-by-step solution

t=3RCln⁡2t=3 R C \ln 2
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