Question

calculate the magnitude of the charge that will flow through a 200ohms galvanometer connected to a 400ohms circular coil of 1000 turns wound on a wooden stick 2cm in diameter, if a magnetic field B=0.0113T parallel to the axis of the stick is decreased suddenly to zero

Answer 1

At first we need to calculate the magnitude of the induced emf on the second coil

Emf induced is defined as,

denotes change in flux in time and N denotes the number of turns in the coil.

Flux of a magnetic field of strength B through an area A is given by,

being the angle between magnetic field and the normal to the surface area.

Given that magnetic field is parallel to the surface and is decreased from 0.0113 T to zero suddenly.

Then, change in flux is,

The coil has 1000 turns and let us assume that the field is changed to zero in time t sec

Hence, magnitude of induced emf in a duration of 1 s is

The galvanometer and the coil are connected in series.

Hence, equivalent resistance is,

So, the current through the galvanometer is,

Hence, the flow of charge in the time t s is

This is the magnitude of charge that will flow through the galvanometer.