Question

A bar magnet oscillates in a magnetic field witj time 4s. If magnet is cut into 2 equal halves perpwndicular to l. Cal tome

Answer 1

Answer:

Let moment of inertia I1=I

Time period T1=T

Magnetic field =B

mass of the magnet =x

When it is cut into two equal pieces, then mass of each piece is x2

Initial moment of inertia

I=112×mass×(length)2

I=112×x×l2

Moment of inertia after it is cut is

I1=112×x2(l2)2

=12×xl28

The magnetic moment of the half price m1=m2

We know T=2πImB−−−−√

TT11=Im1BI1mB−−−−√

=II1×m1m−−−−−−−−√

(ie) TT′=xl2×12×4×212×xl2−−−−−−−−√

=m2m2×2−−−−√

T1=T2

The new time period is T2

Answer : T2