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 galvanometer,`Iproptheta`
`therefore (I_(G))/(I)=(1)/(2)`
`(I-I_(G))S=I_(G)G`

Where G is the resistance of the galvanometer
`(1-(I_(G))/(I))S=((I_(G))/(I))G`
`(1-(1)/(2))xx40(1)/(2)G(because S=40Omega`(Given))
`G=40Omega`