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A galvanometer of resistance, G is shunted by a resistance S ohm. To keep the main current in the circuit unchanged, the resistance to be put in series with the galvanometer is
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S² (S + G) -
SG (S + G) -
G² (S + G) -
G (S + G)
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Correct Option: C
To keep the main current in the circuit unchanged, the resistance of the galvanometer should be equal to the net resistance.
| ∴ G = |  |  | + S' | |
| G + S |
| ⇒ G - | = S' | |
| G + S |
| ∴ S' = | = S' | |
| G + S |
