Question

The poles of a horse-shoe magnet each
of pole strength 2A-m are at 4cm apart.
The magnetic induction at the midpoint
between the poles is
(A) 0.25*10-31
5
(B) 0.5*10-31
(C) 0.125*10-31
(d) 10–3​

Answer 1

Given :

Pole strength of each magnet of horse shoe = 2 Am

Distancr betweem two magnets = 4 cm

To find :

The magnetic induction at the midpoint between the poles

Solution :

B = 2×(uo / 4pi)×(m/r^2)

= 2 × 10^-7 × 2 / (4×10^-2)^2

= 4 × 10^-7 / 16 × 10^-4

= 25 × 10^-5

= 0.25 × 10^-3