Question

Resistance of a galvanometer coil is 600 ohms and a shunt is put in parallel to it. If only 1% of the main current passes through the galvanometer, then multiplying factor K is:

• A. 10
• B. 100
• C. 600
• D. 60

Answer 1

The correct option is B 100

Let current through galvanometer is $Ig=I\times \frac{S}{S+G}$
now according to given conditons , $Ig=\frac{I}{100}=I\times \frac{S}{S+600}$
so $100S=S+600$

by solving we get $S=\frac{600}{99}$
So, multiplying factor K$=\frac{S+G}{S}=\frac{\frac{600}{99}+600}{\frac{600}{99}}=\frac{600+600\times 99}{600}=100$