The angle of dip at the poles and the equator respectively are

Options

A. `30^(@),60^(@)`
B. `0^(@),90^(@)`
C. `45^(@),90^(@)`
D. `90^(@),0^(@)`

Answer

D

Explanation

Since angle of dip of at place is defined as the angle, `delta`, which is the direction of total intensity of earth's magnetic field R makes with a horizontal line in magnetic meridian.
At poles, `B=B_(v) and B_(v)=B sin delta`
`therefore sin delta=1 Rightarrow delta=90^(@)`
`"At equator" B=B_(H)and B_(H)=B cos delta`
`therefore cos delta=1 Rightarrow delta=90^(@)`