A neutral point is obtained at the centre of a vertical circular coil carrying current. The angle between the plane of the coil and the magnetic meridian is

Options

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

Answer

D

Explanation

Magnetic meridian is a vertical `N-S` palne, the earth's magnetic field (`B_(H)`) lies in it. (For more details see magnetism).
To obtain neutral point at the centre of coil, magnetic field due to current (`B`) and `B_(H)` must cancle each other. Hence plane of the coil and magnetic meridian must be perpendicular to each other as shown