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Question: Answered & Verified by Expert
At a certain place a magnet makes 30 oscillations per minute. At another place where the magnetic field is double, its time period will be
PhysicsMagnetic Properties of MatterTS EAMCETTS EAMCET 2012
Options:
  • A $4 \mathrm{~s}$
  • B $2 \mathrm{~s}$
  • C $\frac{1}{2} \mathrm{~s}$
  • D $\sqrt{2} \mathrm{~s}$
Solution:
1600 Upvotes Verified Answer
The correct answer is: $\sqrt{2} \mathrm{~s}$
$\begin{aligned} T=2 \pi & \sqrt{\frac{I}{M B_H}} \\ \therefore \quad \frac{T_1}{T_2} & =\sqrt{\frac{\left(B_H\right)_2}{\left(B_H\right)_1}} \\ T_2 & =T_1 \sqrt{\frac{\left(B_H\right)_1}{\left(B_H\right)_2}} \\ n_1 & =30 \text { oscillation } / \mathrm{min} \\ n_1 & =\frac{1}{2} \text { oscillation } / \mathrm{s} \\ T_1 & =2 \mathrm{~s} \\ T_2 & =2 \sqrt{\frac{B_H}{2 B_H}} \\ = & 2 \times \frac{1}{\sqrt{2}}=\sqrt{2} \mathrm{~s}\end{aligned}$

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