NTA Abhyas JEE Main2020PhysicsCurrent ElectricityPractice
A galvanometer has a current range of 15 mA and a voltage range of 750 mV . To convert this galvanometer into an ammeter of range 25 A , the required shunt is
Options
- A0.8 Ω
- B0.93 Ω
- C0.03 Ω
- D2.0 Ω
Correct answer
C. 0.03 Ω
Step-by-step solution
V = 750 × 10 - 3   V I g = 15 × 10 - 3 A and I = 25   A Using the relation, R = V I g , resistance of galvanometer is = 750 × 10 - 3 15 × 10 - 3 = 50   Ω I g = S S + R × I 15 × 10 - 3 = S S + 50 × 25 S = 0.03   Ω