The true value of dip at a place is `30^(@)` . The vertical plane carrying needle is turned through `30^(@)` from magnetic meridian . Calculate apparent value of angle of dip .

Explanation

`tan delta_(A) = (tan delta)/(cos alpha) = (tan 30^(@))/( cos 45^(@))`
`= (1)/(sqrt3) xx sqrt2 = sqrt((2)/(3))`
`delta_(A) = tan^(-1) (sqrt((2)/(3)))`