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A compass needle of magnetic moment 60...

A compass needle of magnetic moment 60 `Am^(2)` pointing geopgraphical north at a place where the horizontal component of earth fiedl is 40 `mu Wbm^(-2)` experiences a torque of `1.2 xx10^(-3)` Nm the declination of the place is

A

`15^(@)`

B

`30^(@)`

C

`45^(@)`

D

`60^(@)`

Text Solution

Verified by Experts

The correct Answer is:
B
`tau =MH sin theta`
`therefore sin theta =(tau)/(MH)=1/2 therefore theta =30^(@)`
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