Question

A galvanometer of resistance `G` is shunted by a resistance `S ohm`. To keep the main current in the circuit uncharged, the resistnace to be put in series with the galvonmeter
A. `(S^(2))/((S + G))`
B. `(SG)/((S + G))`
C. `(G^(2))/((S + G))`
D. `(G)/((S + G))`

Answer 1

Correct Answer - C
Current will be uncharged if resistance remain the same, so
`G = (GS)/(G + S) + R`
`R = G - (GS)/(G + S) implies R = (G^(2))/(G + S)`