Question 39: Magnetism and Matter

Question

Two bar magnets oscillate in a horizontal plane in earth's magnetic field with time periods of $$3 \mathrm{~s}$$ and $$4 \mathrm{~s}$$ respectively. If their moments of inertia are in the ratio of $$3: 2$$, then the ratio of their magnetic moments will be:

Accepted Answer

$$T = 2\pi \sqrt {{I \over {M{B_H}}}} $$
$$ \Rightarrow {{{T_1}} \over {{T_2}}} = \sqrt {{{{I_1}} \over {{I_2}}}} \sqrt {{{{M_2}} \over {{M_1}}}} $$
$$ \Rightarrow {3 \over 4} = \sqrt {{3 \over 2}} \sqrt {{{{M_2}} \over {{M_1}}}} $$
$$ \Rightarrow {{{M_1}} \over {{M_2}}} = {3 \over 2} 	imes {{16} \over 9} = {8 \over 3}$$

Answer

2 : 1

Answer

8 : 3

Answer

1 : 3

Answer

27 : 16

Magnetism and Matter

Two bar magnets oscillate in a horizontal plane in earth's magnetic field with time periods of $3 \mathrm{~s} and 4 \mathrm{~s} respectively. If their moments of inertia are in the ratio of 3: 2$, then the ratio of their magnetic moments will be:

Choose the correct answer: