Question

A short bar magnet has a magnetic moment of 0.48 J T-1. The magnitude and direction of magnetic field produced by the magnet at a distance of 10 cm from the centre of the magnet on its axis is

• A. 0.48 × 10-4 along N-S direction
• B. 0.28 × 10-4 T along S-N direction
• C. 0.28 × 10-4 T along N-S direction
• D. 0.96 × 10-4 T along S-N direction

Answer 1

Answer: (D)

0.96 × 10-4 T along S-N direction

Answer 2

: On the axis of the magnet,

Here, $\frac { \mu _ { 0 } } { 4 \pi } = 10 ^ { - 7 } \mathrm { Am } ^ { - 2 }$

m

Then, $\mathrm { B } = \frac { 10 ^ { - 7 } \times 2 \times 0.48 } { ( 0.1 ) ^ { 3 } }$

along S –N direction.