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MHT CET · Physics · Magnetic Effects of Current

A magnetic needle of magnetic moment \(6 \times 10^{-2} \mathrm{Am}^2\) and moment of inertia \(9.6 \times 10^{-5} \mathrm{~kg} \mathrm{~m}^2\) performs simple harmonic motion in a magnetic field of 0.01 T . Time taken to complete 10 oscillations is [Take \(\pi=3 \cdot 14\) ]

  1. A 0.2512 s
  2. B 2.512 s
  3. C 25.12 s
  4. D \(251 \cdot 2 \mathrm{~s}\)
Verified Solution

Answer & Solution

Correct Answer

(C) 25.12 s

Step-by-step Solution

Detailed explanation

Period of oscillation \(T=2 \pi \sqrt{\frac{\mathrm{I}}{\mathrm{MB}}}\)
\(\begin{aligned}
& =2 \pi \sqrt{\frac{9.6 \times 10^{-5}}{6 \times 10^{-2} \times 0.01}} \\
& =2.512 \mathrm{~s}
\end{aligned}\)
\(\therefore \quad\) Time taken for 10 oscillations \(=2.512 \times 10\)
\(=25.12 \mathrm{~s}\)