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

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 T 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

Tardigrade Admin · Accepted Answer

On the axis of the magnet B = (μ0/4π) ⋅ (2m/d3) Here, (μ 0/4π ) = 10-7 A m-2 m = 0.48 J T-1, d = 10 cm = 0.1 m Then, B = (10-7× 2 × 0.48 /(0.1)3) = 0.96 × 10-4 T, along S-N direction.

Q. 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 $10 c m$ from the centre of the magnet on its axis is

$0.48 \times 1 0^{- 4} T$ along $N - S$ direction

$0.28 \times 1 0^{- 4} T$ along $S - N$ direction

$0.28 \times 1 0^{- 4} T$ along $N - S$ direction

$0.96 \times 1 0^{- 4} T$ along $S - N$ direction

On the axis of the magnet
$B = \frac{μ _{0}}{4 π} \cdot \frac{2 m}{d ^{3}}$
Here, $\frac{μ _{0}}{4 π} = 1 0^{- 7} A m^{- 2}$
$m = 0.48 J T^{- 1}, d = 10 c m = 0.1 m$
Then, $B = \frac{1 0 ^{- 7} \times 2 \times 0.48}{( 0.1 ) ^{3}}$
$= 0.96 \times 1 0^{- 4} T$ , along $S - N$ direction.

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

0.48×10−4T along N−S direction

0.28×10−4T along S−N direction

0.28×10−4T along N−S direction

0.96×10−4T along S−N direction