an ammeter of resistance 0.1ohms has a full scale deflection of 50mA .

Determine the resultant full scale deflection of the meter when a shunt of 0.0111 ohms is connected across its terminals?

2 answers

voltage across meter for full scale: I*R=.1*.050=.005 volts
total current under .005 volts with .1 in parallel with .0111
...resistance= 1/R=1/.1 + 1/.0111
R= .00111/(.1111)=.0100ohms
full scale reading with then be at V/R=. .05//01 =5 amps
check my work.
Im = 50 mA = 0.05 A = Current through meter.
Ir = 0.10/0.0111 * 0.05A = 0.450A = Current through resistor.
Im + Ir = 0.05 + 0.450 = 0.500A = Full-scale reading.