A galvanometer having a coil resistance of `60 Omega` shows full scale defection when a current of `1.0 A` passes thoguth it. It can vbe convered into an ammeter to read currents up to `5.0 A` by

Options

A. Putting in parallel a resistance of `240 Omega`
B. Putting in series a resistance of `15 Omega`
C. Putting in series a resistance of `240 Omega`
D. Putting in parallel a resistance of `15 Omega`

Answer

D

Explanation

`R_(G) = 60 Omega`

`I_(g) = 1 amp`,
`I_(g)R_(G) = (I-I_(g))S`
`rArr S = (I_(g)R_(G))/(I - I_(g)) = 60/(5-1) = 15 Omega`