MHT CET Medical202621 April 2026Evening ShiftPhysicsCurrent ElectricityActual
An ammeter of resistance R give a full scale deflection when a current of 3 A passes through it. If it is to measure maximum current of 10 A , the shunt required is
Options
- A3R/5
- B2R/5
- C3R/7
- D4R/7
Correct answer
C. 3R/7
Step-by-step solution
Given, resistance of the ammeter is R . Full scale deflection current, I_g = 3 A . Maximum current to be measured, I = 10 A . Let the required shunt resistance be S . Since the shunt is connected in parallel with the ammeter, the potential difference across both will be the same. I_g R = (I - I_g) S 3 R = (10 - 3) S 3R = 7S S = 3R 7 Answer: 3R/7