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A certain current on passing through a galvanometer produces a deflection of 100 divisions. When a shunt of one ohm is connected, the deflection reduces to 1 division. The galvanometer resistance is

A certain current on passing through a galvanometer produces a deflection of 100 divisions. When a shunt of one ohm is connected, the deflection reduces to 1 division. The galvanometer resistance is Correct Answer 99 Ω

CONCEPT:

  • Galvanometer: It is an electromechanical instrument used for detecting and indicating the electric current and is called a Galvanometer.
  • The electric Current through galvanometer is given by:

Ig = kθ

Where k = galvanometer constant, θ is angular displacement (number of divisions), Ig = Current through a galvanometer

  • Shunt: A resistor connected in parallel with a galvanometer to increase its range under certain conditions is called a shunt.
    • It allows only a known fraction of the current to pass through the galvanometer.

EXPLANATION:

Given that,S = 1 Ω, I = 100k and Ig = 1k.

IS = I - Ig

100 – 1 = 99k

G = IS × S/Ig = 99k × 1/1 = 99 Ω

The Correct option is 2.

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