COMEDK202510 May 2025Evening ShiftPhysicsCurrent ElectricityActual
A galvanometer of 50 resistance is converted into an ammeter using a shunt resistance of 10 . If the same resistance is used to convert the same galvanometer in to a voltmeter, what would be the ratio of the resistance of the ammeter to the resistance of the voltmeter?
Options
- A5: 36
- B5: 6
- C1: 5
- D5: 1
Correct answer
A. 5: 36
Step-by-step solution
Let G = 50 be the resistance of the galvanometer and S = 10 be the shunt resistance. The resistance of an ammeter R_ A is given by the parallel combination of the galvanometer and the shunt resistance: R_ A = G S G + S = 50 10 50 + 10 = 500 60 = 50 6 = 25 3 . When the same resistance S = 10 is used to convert the galvanometer into a voltmeter, it is connected in series with the galvanometer. The resistance of the voltmeter R_ V is given by: R_ V = G + S = 50 + 10 = 60 . The ratio of the resistance of the ammeter to