A dip needle lies initially in the magnetic merdian when it shows an angle of dip `theta` at a place. The dip circle is rotated through an angle x in the horizontal plane and then it shows an angle of dip `theta^(')`. Then `tantheta^(')/tantheta` is

Options

A. `1/(cos x)`
B. `1/(sin x)`
C. `1/(tan x)`
D. `cos x`

Answer

A

Explanation

In the first case
`tan theta=B_(V)/B_(H) …(i)`
Second case
`tan theta^(')=B_(V)/(B_(H) cos x) …(ii)`
From equations (i) and (ii), `(tan theta^('))/tan theta=1/(cosx)`