The magnetometer of the previous problem is used with the same magent in `Tan-B` position. Where should the magnet be placed to produce a `37^@` deflection of the needle?

Explanation

`(M)/(B_(H))` (As found in the previous problem)
`= 3.75 xx 10^(8)A - m^(2)//T`
`theta = 37^(@)`
`Since `(M)/(B_(H)) = (4 pi)/(mu_(0)) (d^(2) + l^(2))^(8//9)`
Since `1 ltlt d neglecting 1 w.r.t.d.`
` rArr (M)/(B_(H)) = (4 pi)/(mu_(0)) d^(2) tan theta` lt.brgt`rArr 3.75 xx 10^(2) = 7 xx (1)/(10^(-7)) xx d^(2) xx 0.75`
` d^(2) = (3.75 xx 10^(2) xx 10^(-7))/(0.75) `
`= 5 xx 10^(-4)`
` d = ssqrt(5 xx 10^(-4))`
` = 0.079 m = 7.9 cm`