JEE Main202429 Jan 2024Morning ShiftPhysicsCurrent ElectricityActual
A galvanometer having coil resistance 10 Ω shows a full scale deflection for a current of 3 mA . For it to measure a current of 8 A , the value of the shunt should be:
Options
- A3 × 10 - 3 Ω
- B4 . 85 × 10 - 3 Ω
- C3 . 75 × 10 - 3 Ω
- D2 . 75 × 10 - 3 Ω
Correct answer
C. 3 . 75 × 10 - 3 Ω
Step-by-step solution
Given G = 10 Ω , I g = 3 mA and I = 8 A . Let's consider the following figure: From the figure, we have I g G = I - I g S ⇒ S = I g G I - I g ⇒ S = 3 × 10 - 3 10 8 - 0 . 003 = 3 . 75 × 10 - 3 Ω