Question

Why is it necessary to set the plane of the coil in magnetic meridian?

Answer 1

Answer:

Tangent galvanometer is based on the principle of tangent law . For tangent law to be applicable, the magnetic field of the coil should be perpendicular to needle of magnetometer of tangent galvanometer which is aligning in NS direction in a horizontal plane .Thus the field of coil must be along EW line. Moreover the needle of magnetometer is free to rotate in horizontal plane. To meet all these requisites, the coil should be in a vertical plane containing NS line, which is magnetic meridian.

Answer 2

Answer:

A line that passes across the north and south magnetic poles and resembles a huge circle on the surface of the globe it necessary to set the plane of the coil in magnetic meridian.

Explanation:

The magnetic field created by the current in the coil of a tangent galvanometer is perpendicular to the plane of the coil in an East-West direction when the coil's plane is situated in the magnetic meridian and current is passed through the coil. The earth's horizontal component runs from south to north. The tangent galvanometer's operating principle assures that the horizontal component of the earth's magnetic field will not interfere with the field of the coil.

• The magnetic meridian should be parallel to the plane of the coil of the tangent galvanometer. Reason (R): Tangent law can be applied because the coil's magnetic field is made to be perpendicular to the horizontal component of the earth's magnetic field.
• The magnetic field created by the current in the coil of a tangent galvanometer is perpendicular to the plane of the coil in an East-West direction when the coil's plane is situated in the magnetic meridian and current is passed through the coil.
• The earth's horizontal component runs from south to north. The current (I) can then be measured by noting the deflection because the magnetic needle of the tangent galvanometer will then obey the tangent law.