What is Tangent Galvanometer? Explain briefly.

 

What are the possible conceptual questions from the chapter Magnetism & Matter?

Tangent galvanometer is an instrument for measuring small electric currents. With it one can measure the horizontal component of Earth's magnetic field also. It consists of a coil of insulated copper wire wound on a circular non-magnetic frame. Its working is based on the principle of the tangent law of magnetism B = B_h tanθ.

When a current is passed through the circular coil, a magnetic field (B) is produced at the centre of the coil in a direction perpendicular to the plane of the coil. The TG is arranged in such a way that the horizontal component of Earth’s magnetic field (B_h) is in the direction of the plane of the coil.

The magnetic needle is then under the action of two mutually perpendicular fields. If θ is the deflection of the needle, then according to tangent law, we get

 

This is how, one can measure the horizontal component of Earth's magnetic field.

 

NOTE: Kindly post the other question as a separate query.