Question

The moment of inertia as well as the time periods of two magnets are in the ratio $1:2$. The ratio of their magnetic moments is

• A. $2:1$
• B. $1:2$
• C. $4:3$
• D. $3:4$

Answer 1

The correct option is A $2:1$

$\frac{I_1}{I_2}=\frac{1}{2}$ and,

$\frac{T_1}{T_2}=\frac{1}{2}$

or, $\frac{2\pi \sqrt{\frac{I_1}{M_{1}B}}}{2\pi \sqrt{\frac{I_2}{M_{2}B}}}=\frac{1}{2}$

$\frac{I_1}{I_2}\times \frac{M_2}{M_1}=\frac{1}{4}$

$\therefore \frac{M_1}{M_2}=\frac{2}{1}$