Question

A moving coil sensitive galvanometer gives at once much more deflection. To control its speed of deflection
A) A high resistance is to be connected across its terminals
B) A magnet should be placed near the coil
C) A small copper wire should be connected across its terminals
D) The body of galvanometer should be earthed

Answer 1

Hint:To solve this problem, use the concept of resistance and its relation to current, and the principle of a moving coil galvanometer. Analyze the effect of each given option on the speed of deflection of the moving coil galvanometer.

Complete answer:
Understand the concept of resistance and its relation to current. Resistance is a property of a circuit that opposes the flow of current through it. A high resistance in a circuit reduces the flow of current, thus reducing the deflection in a moving coil galvanometer.

Analyze the effect of each given option on the speed of deflection of the moving coil galvanometer. A high resistance is to be connected across its terminals (Option A) to control the speed of deflection as it reduces the current flowing through the coil and thus reduces the deflection.

A magnet should not be placed near the coil (Option B) as it increases the deflection. A small copper wire should not be connected across its terminals (Option C) as it does not have any effect on the deflection. The body of the galvanometer should not be earthed (Option D) as it does not affect the deflection.

The correct option is A) A high resistance is to be connected across its terminals.

Note: A moving coil galvanometer is a type of instrument used for measuring small electric currents. The speed of deflection of the moving coil galvanometer can be controlled by reducing the current flowing through it by increasing the resistance in the circuit. This is achieved by connecting a high resistance across the terminals of the moving coil galvanometer.