The plane of dip circle is set in the geographic meridian and the apparent dip is `theta_(1)`. It is then set in a vertical plane perpendicular to the geographic meridian. Now, the apparent dip is `theta_(2)`. The angle of declination `theta` at that place is

Options

A. `tan alpha=sqrt(tantheta_(1) tantheta_(2))`
B. `tan alpha=sqrt((tantheta_(1))( tantheta_(2)))`
C. `tan alpha=(tantheta_(1))/(tantheta_(2))`
D. `tan alpha=(tantheta_(2))/(tantheta_(1))`

Answer

C

Explanation

`tantheta_(1)=(tandelta)/(cos alpha)` or `cos alpha=(tan delta)/(tantheta_(1)) …(i)`
Again, `tantheta_(2) =(tandelta)/(sin alpha)`
or `sin alpha=(tandelta)/(tantheta_(2)) …(ii)`
`((2))/((1))` gives `tan alpha =(tantheta_(1))/(tantheta_(2))`