Question

In a dead beat galvanometer, the coil is wound on a frame made of:

Answer 1

Hint:The eddy currents that are produced in the galvanometer will oppose the oscillation of the coil. Electromagnetic dumping is used in designing the deadbeat galvanometer. Eddy currents are also known as Foucault currents. Eddy currents oppose the motion of the conductor in the field.

Complete step-by-step solution:
An instrument that is used for measuring small currents is known as a galvanometer. When a current is detected by a galvanometer then it shows some deflection in the pointer of the galvanometer.
If a piece of metal is kept in a changing magnetic field then the free electrons in the conductor experience magnetic force by the changing field and they begin to move. The moving of the electrons in the metal piece gives rise to the electric currents and hence it is known as eddy currents and these eddy currents flow in such a direction that they oppose the motion of the conductor in the field.
A simple galvanometer is known as a deadbeat galvanometer because due to the rotation of the coil, eddy currents are produced in the metallic frame which oppose the further movement of the coil and hence the oscillations are dead, therefore it is named so.
When the current flows in the coil then the coil gets deflected and when the current stops then the coil still oscillates about its equilibrium position and the eddy currents that are generated in the metallic frame opposes the oscillatory motion of the coil.
The coil of the deadbeat galvanometer is wound on the frame made up of metal because the eddy currents that will be produced in the metallic frame will quickly bring the oscillation of the coil to rest. A dead beat galvanometer is mostly used to determine the current which is used in various experiments.

Note:Eddy currents produce a dumping effect which is used in galvanometer to make it a dead beat galvanometer and electromagnetic dumping occurs when the coil suffers some oscillations with the help of eddy currents. When the eddy currents oppose the motion of the coil then it is said that the oscillations are damped.