The true value of dip at a place is `45^@`. If the vertical plane carrying the needle is turned through `60^@` from the magnetic meridian, find the inclination of the needle (i.e. what will be the apparent value of dip)?

Answer

`63^@ 26^'`

Explanation

`delta=45^@`, `theta=60^@`, `delta^'=?`
`tan delta^'=(tan delta)/(cos theta)=(tan 45^@)/(cos 60^@)=2`
`delta^'=tan^-1(2)=63^@26^'`