A dip circle is adjusted so that its needle moves freely in the magnetic meridian. In this position, the angle of dip ia `40^(@)`. Now the dip circle is rotated so that the plane in which the needle moves makes an angle of `30^(@)` with the magnetic meridian. In this position the needle will dip by an angle

Options

A. `40^(@)`
B. `30^(@)`
C. More than `40^(@)`
D. Less than `40^(@)`

Answer

C

Explanation

`tan theta=B_(V)/B_(H)`
If apparent dip is `theta^(')` then
`tan theta^(')=B_(V)^(')/B_(H)^(')=B_(V)/(B_(H) cos 30^(@))=B_(V)/(B_(H)xxsqrt(3)/2)`
`implies tantheta^(')=(2/sqrt(3))tanthetaimpliestantheta^(') gt tanthetaimpliestheta^(')gttheta`