Question:
A magnetic needle of magnetic moment $6.7 \times 10^{-2} \mathrm{Am}^{2}$ and moment of inertia $7.5 \times 10^{-6} \mathrm{~kg} \mathrm{~m}^{2}$ is performing simple harmonic oscillations in a magnetic field of $0.01 \mathrm{~T}$. Time taken for 10 complete oscillations is :
Correct Option: , 3
Solution:
