Question

Two identical short bar magnets, each having magnetic moment M are placed a distance of 2d apart with axes perpendicular to each other in a horizontal plane. The magnetic induction at a point midway between them is.

(a) √2(μ0/4π) (M/d3)

(b) √3(μ0/4π) (M/d3)

(c) √4(μ0/4π) (M/d3)

(d) √5(μ0/4π) (M/d3)

Answer 1

The correct option (d) √5(μ0/4π) (M/d3)

Explanation:

Let point P is midway between them due for magnet 1, induction at P is

B1 = (μ0/4π)(2M/d3) …………… (axis point)

due to magnet 2, induction at P is

B2 = (μ0/4π)(M/d3)…….. [Perpendicular point]

Bnet = √[(B12) + (B22)]

= √[{(μ0/4π)(2M/d3)}2 + {(μ0/4π)(M/d3)2}]

= (μ0/4π)(M/d3)√(4 + 1) = [{√(5)Mμ0}/(4πd3)]