Question

A bar magnet of magnetic moment 200 A-m² is suspended in a magnetic field of intensity 0.25 N/A-m. The couple required to deflect it through 30^o is

• A. 50 N-m
• B. 25 N-m
• C. 20 N-m
• D. 15 N-m

Answer 1

Answer: (B)

25 N-m

Answer 2

$\tau = M B \sin \theta$

$\tau = 200 \times 0.25 \times \sin 30 ^ { \circ } = 25 \mathrm {~N} \times \mathrm { m }$