The deflection in a moving coil galvanometer is reduced to half when it is shunted with a 40`Omega` coil. The resistance of the galvanometer is

Options

A. 80`Omega`
B. 40`Omega`
C. 20`Omega`
D. 15`Omega`

Answer

B

Explanation

In case of a galvameter ,`Iproptheta`
`:.(I_(G))/(I)=(1)/(2)`
`(I-I_(G))S=I_(G)G` where G is the resistance of the galvameter
`(1-(I_(G))/(I))S=((I_(G))/(I))G`
`(1-(1)/(2))xx40=((1)/(2))G" "(":.S=40Omega(Given))`
G=40`Omega`