A short magnet produces a dfection of `30^(@)` when placed at certain distance in tanA position of magnetometer. If another short magnet of double the length and thrice the pole strength is placed at the same distance in tabB position of the magnetometer, the deflection produced will be

Options

A. `60^(@)`
B. `30^(@)`
C. `45^(@)`
D. None of these

Answer

1

Explanation

In tan A position
`(nu_(0))/(4pi)(2M)/(d^(3))=Br+tan 30^(@) =(B_(H))/(sqrt(3))…1`
Magnetic momment of second magnet,
`M'=(3m)(2xx2l)=6M`
In tan B position,
`(mu_(0))/(4pi)(6M)/(d^(3))=B_(h) tan theta`
dividing eq (2) by (1) we get
`6/2 = (tan theta)/(1//sqrt(3))`
`or tan theta = sqrt(3)`
`or theta = 60^(@)`