The dipole moment of a short bar magnet is 1.25 A m 2. The magnetic field on its axis at a distance of 0.5 metre from the centre of the magnet is

Question

The dipole moment of a short bar magnet is 1.25 A m 2. The magnetic field on its axis at a distance of 0.5 metre from the centre of the magnet is (A) 1.0 × 10-4 N / Am (B) 4 × 10-2 N / Am (C) 2 × 10-6 N / Am (D) 6.64 × 10-8 N / Am

Tardigrade Admin · Accepted Answer

B=(μ0/4 π) (2 M/d3)=10-7 × (2 × 1.25/(0.5)3) =2 × 10-6 N / A - m

Q. The dipole moment of a short bar magnet is $1.25 A m^{2}$ . The magnetic field on its axis at a distance of $0.5$ metre from the centre of the magnet is

$1.0 \times 1 0^{- 4} N / A m$

$4 \times 1 0^{- 2} N / A m$

$2 \times 1 0^{- 6} N / A m$

$6.64 \times 1 0^{- 8} N / A m$

$B = \frac{μ _{0}}{4 π} \frac{2 M}{d ^{3}} = 1 0^{- 7} \times \frac{2 \times 1.25}{( 0.5 ) ^{3}}$
$= 2 \times 1 0^{- 6} N / A - m$

Q. The dipole moment of a short bar magnet is 1.25Am2. The magnetic field on its axis at a distance of 0.5 metre from the centre of the magnet is

1.0×10−4N/Am

4×10−2N/Am

2×10−6N/Am

6.64×10−8N/Am