For a Wheatstone bridge at balance, the bridge is **insensitive** to changes in the galvanometer's internal resistance. This is because:
AThe bridge wire has uniform cross-section
BThe galvanometer is short-circuited
CThe EMF source is removed
DThe galvanometer current $I_g$ is zero at balance, so no voltage drops across it
Answer & Solution
Correct answer: D. The galvanometer current $I_g$ is zero at balance, so no voltage drops across it
At balance $I_g = 0$, so the voltage across the galvanometer is 0 V regardless of its resistance. Therefore the balance condition $P/Q = R/S$ doesn't depend on $G$.
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