TS EAMCET 9-Sep-2020 Shift 1 Solved Paper

Let magnetic dipole moment of given magnet is M. Then, its oscillation time period is
T=2π√‌

I

MB

=2s( given )
where, I= moment of inertia =‌

ωl2

12

and M= magnetic dipole moment of magnet. When magnet is cut into 3 parts, each part length is l/3 and mass of each part will be ω/3 So, moment of inertia of each part will be
I′=‌

ω′l2

12

=‌

‌ ω 3 × l2 9

12

=‌

1

27

×I
Also, magnetic dipole moment of each part will be
M′=‌

M

3

Now, when these parts are placed one over other with like poles together,
Moment of inertia of combination
=I1=3×‌

1

27

I=‌

1

9

I
Also, dipole moment of combination is
M1=3×‌

M

3

=M
Hence, time period of oscillation of combination is