MHT CET Medical202622 April 2026Morning ShiftPhysicsCurrent ElectricityActual
When a galvanometer is shunted by a resistance S, its current capacity increases n times. If the same galvanometer is shunted by another resistance S', its current capacity will increase to n' . The value of n' in terms of n, S, and S' is
Options
- AS(n-1)-S' S'
- B(n+1)S S'
- CS(n-1)+S' S'
- Dn+S S'
Correct answer
C. S(n-1)+S' S'
Step-by-step solution
Let the resistance of the galvanometer be G and its initial current capacity be I_g . When shunted by a resistance S , the new current capacity becomes I = n I_g . Using the principle of parallel combination, the potential difference across the galvanometer and the shunt are equal: I_g G = (I - I_g) S I_g G = (n I_g - I_g) S G = (n - 1) S When the galvanometer is shunted by another resistance S' , the new current capacity becomes I' = n' I_g . Similarly, we can write: I_g G = (I' - I_g) S' I_g G = (n' I_g - I_g) S'