The magnetometer of the previous problem is used with the same magnet in Tan-B position. Where should the magnet be placed to produces a 37° deflection of the needle?

Question

Philoid · Accepted Answer

Given,

separation between the magnet and the needle d = 10cm =0.1 m

deflection in the magnetometer in the given position when placed in the magnetic field of a short magnet, θ = 37°

let M be the magnetic moment of the magnet and B_H be earth's horizontal magnetic field.

according to magnetometer theory

for short magnet → d ≫≫≫ l

deflection in the magnetometer θ =37°

From the magnetometer theory in Tan-B position, we have

-----------------------(1)

l≪≪≪d

d = 0.079370m =7.9370cm