Question

To convert a 400 m V range galvanometer of resistance `20 Omega` into a ammeter of 100 m A ranges , the required shunt resistance to be connected is
A. `5Omega`
B. `4Omega`
C. `2.5Omega`
D. `1.5Omega`

Answer 1

Correct Answer - A
`I_g=(V_g)/(G)=(400)/(20)=20xx10^-3A =20 m A `
Now , `S=(I_g .G)/(I-I_g)`
`S=(20xx20)/(100-20)=(20xx20)/(80)=5 Omega` .