Question

Assertion (A) : The torque acting on a current carrying coil is maximum when it is suspended in a radial magnetic field. Reason (R) : The torque tends to rotate the coil on its own axis.

A galvanometer is converted into a voltmeter of range (0 – V) volt using a resistor of 9900 Ω. If a resistor of 4900 Ω is used, the range becomes half, i.e. (0 – V/2) volt. Calculate : (a) resistance of the galvanometer (b) resistance required to convert it into a voltmeter of range (0 – 2V) volt.

Briefly explain why and how a galvanometer is converted into an ammeter.

Write the principle and explain the working of a moving coil galvanometer. A galvanometer as such cannot be used to measure the current in a circuit. Why ?