A galvanometer coil has a resistance of 15 ohm and gives full scale deflection for a current of 4 mA. To convert it to an ammeter of range 0 to 6 A,

Options

A. `10 m Omega` resistance is to be connected in parallel to the galvanometer
B. `10 m Omega` resistance is to be connected in series with the galvanometer
C. `0.1 Omega` resistance is to be connected in parallel to the galvanometer
D. `0.1 Omega` resistance is to be connected in series with the galvanometer.

Answer

A

Explanation

A galvanometer can be converted into an ammeter by connecting a shunt resistance in parallel to the galvanometer, given by
`S=(I_(g)G)/(I-I_(g))=(4xx10^(-3)xx15)/(6-4xx10^(-3))=10xx10^(-3)Omega = 10 m Omega`.