A galvanometer, whose resistance is 50 ohm, has 25 division in it. When a current of 4×10−4A passes through it, is its needle (pointer) deflects by one division. To use this galvanometer as a voltmeter of range 2.5 V, it should be connected to a resistance of:
The correct option is C: 6200ohm
Given Data:
Resistance of galvanometer, Rg=50ohm
Current passing through the galvanometerIg= 4×10−4A
Suppose we connect a residstance of Rohm in series
So, 2.5=(R+Rg)× 4×10−4A
2.5=(R+50)× 4×10−4A
R+50=2.54×10−4=6200ohm