Question

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

• A. $0^{\circ }$
• B. ${45}^{\circ }$
• C. ${60}^{\circ }$
• D. ${90}^{\circ }$

Answer 1

The correct option is D ${90}^{\circ }$

The magnetic meridian is along $N-S$ plane, and the earth's magnetic field ${\overrightarrow{B}}_H$ lies along it.

To obtain neutral point at the centre of coil, magnetic field due to current in the coil $\overrightarrow{B}$ and ${\overrightarrow{B}}_H$ must cancel each other.

Hence, plane of the coil and magnetic meridian must be perpendicular to each other as shown below.


Hence option $\left(D\right)$ is the correct answer.