JEE Main201910 Apr 2019Morning ShiftPhysicsCurrent ElectricityActual
A moving coil galvanometer allows a full scale current of 10 - 4 A . A series resistance of 2 × 10 4 Ω is required to convert the galvanometer into a voltmeter of range 0 - 5 V . Therefore, the value of shunt resistance required to convert the above galvanometer into an ammeter of range 0 - 10 m A is:
Options
- A100 Ω
- B200 Ω
- C300 Ω
- D10 Ω
Correct answer
C. 300 Ω
Step-by-step solution
i g = 10 - 4   A i = 10 × 10 - 3   A R V = 20   k Ω i g G + i g   R V = 5 i g G = i - i g R A R A = i g G i - i g = i g 5 - i g R V i - i g i g R A = 5 - i g R V i - i g ≈ 300   Ω