A bar magnet of moment of inertia 9 × 10-5 kg m2 placed in a vibration magnetometer and oscillating in a uniform magnetic field 16 π2 × 10-5 T makes 20 oscillations in 15 s. The magnetic moment of the bar magnet is

Question

A bar magnet of moment of inertia 9 × 10-5 kg m2 placed in a vibration magnetometer and oscillating in a uniform magnetic field 16 π2 × 10-5 T makes 20 oscillations in 15 s. The magnetic moment of the bar magnet is (A) 3 A-m2 (B) 2 A-m2 (C)  5 A-m2 (D) 6 A-m2

Tardigrade Admin · Accepted Answer

Given, I=9 × 10-5 kg - m 2 B=16 π2 × 10-5 T T=(15/20)=0.75 The time period T =2 π √(I/M B) T2 =4 π2 × (I/M B) M =4 π2 × (I/T2 B) =4 π2 × (9 × 10-5/16 π2 × 10-5 ×(0.75)2) =(9/4 × 0.5625) =(9.00/2.25)=4 A - m 2

Q. A bar magnet of moment of inertia $9 \times 1 0^{- 5} k g m^{2}$ placed in a vibration magnetometer and oscillating in a uniform magnetic field $16 π^{2} \times 1 0^{- 5} T$ makes $20$ oscillations in $15 s$ . The magnetic moment of the bar magnet is

$3 A - m^{2}$

$2 A - m^{2}$

$5 A - m^{2}$

$6 A - m^{2}$

$4 A - m^{2}$

Q. A bar magnet of moment of inertia 9×10−5kgm2 placed in a vibration magnetometer and oscillating in a uniform magnetic field 16π2×10−5T makes 20 oscillations in 15s. The magnetic moment of the bar magnet is

3A−m2

2A−m2

5A−m2

6A−m2

4A−m2