Question

A small AC dynamo is connected to a galvanometer and gently rotated, then the needle of the galvanometer.
(A) move towards the left.
(B) move towards the right.
(C) remains in the same position.
(D) moves towards both right and left.

Answer 1

A dynamo is an electrical generator that generates direct current with the help of a commutator. Dynamo was the first electrical generator that was efficient enough to provide the necessary power for industry, and they are the foundation for many other electric-power transformation devices.

Complete step-by-step solution:
An AC generator works on the principle of electromagnetic induction in which electric current is produced in the coil which is kept in a magnetic field. Inside the galvanometer there is a permanent magnet and an electromagnet and when the magnetic field is produced inside the coil is in opposite nature to the nature of magnetic field of permanent magnet the needle deflects and when the nature of magnetic field become same of each other’s then also needle deflects. In both cases the needle gets deflected.
A small AC dynamo is connected to a galvanometer which when rotated gently, the needle of the galvanometer displaces towards both right and left direction. The displacement of the needle of a galvanometer denotes a current flowing through the small stator winding which is present interior to the device. The more the amount of current flowing through the coil the larger the magnetic disruption occurs.
Therefore, A small AC dynamo is connected to a galvanometer and gently rotated, then the needle of the galvanometer. Move towards both right and left.
Hence the option (D) moves towards both right and left is the correct answer.

Note:- An electric generator contains two fixed permanent magnets with their opposing poles facing each other. A rectangular conducting coil is kept in between the magnets. The coil is linked to a rotating shaft and the exterior load circuit through brushes. The rotation of the coil leads the way to the generation of electric current in the coil in line with Faraday's law of electromagnetic induction.