Question

The current flowing through moving coil galvanometer is 20% of the current to be measured. The resistance of moving coil galvanometer is 48 `Omega`, then shunt required is ____________.

Options

• 48 `Omega`

• 12 `Omega`

• 96 `Omega`

• 24 `Omega`

Answer 1

The current flowing through moving coil galvanometer is 20% of the current to be measured. The resistance of moving coil galvanometer is 48 `Omega`, then shunt required is 12 `Omega`.

Explanation:

G = 48 `Omega`

`"i"_g = 20%  "of i" = 20/100 "i" = 0.2  "i"`

`"i"_"g" "G" = ("i" - "i"_"g")"S"`

`S = ("i"_"g" "G")/("i" - "i"_"g") = (0.2  "i"  "G")/("i" (1 - 0.2))`

`= (0.2 "G")/0.8`

`= 1/4 xx 48`

`= 12  Omega`