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Question: Answered & Verified by Expert
The magnetic flux in a closed circuit of resistance $10 \Omega$ varies with time as $\phi=\left(2 \mathrm{t}-4 \mathrm{t}^{2}+1\right)$. The current in the loop will change its direction after a time of
PhysicsElectromagnetic InductionVITEEEVITEEE 2016
Options:
  • A $0.25 \mathrm{sec}$
  • B $0.5 \mathrm{sec}$
  • C $1 \mathrm{sec}$
  • D none
Solution:
1917 Upvotes Verified Answer
The correct answer is: $0.25 \mathrm{sec}$
$\begin{aligned} \mathrm{e} &=-\frac{\mathrm{d} \phi}{\mathrm{dt}}=[-2+8 \mathrm{t}+0] \\ & \Rightarrow 8 \mathrm{t}=2 \Rightarrow \mathrm{t}=\frac{1}{4} \mathrm{sec}=0.25 \mathrm{sec} \end{aligned}$

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