Question

a galvanometer of resistance 100 ohm gives full scale deflection at 10 Milli ampere current what should be the value of stunts that it can measure the current of hundred milliampere​

Answer 1

we know, a shunt is connected in parallel combination with a galvanometer.

potential difference across shunt = potential difference across galvanometer.

or, $I_s\times S=I_g\times G$...(1)

given, current through system of galvanometer and shunt, $I_t$ =100mA = 0.1A

current through galvanometer, $I_g$ = 10mA = 0.01A

so, current through shunt, $I_s=I_t-I_g$

= 0.1 - 0.01 = 0.09A

now, from equation (1),

0.09A × S = 0.01A × 100 ohm

or, S = 1/0.09 = 100/9 = 11.11 ohm

hence, resistance of shunt is 11.11ohm