In a metre bridge experiment, the balance length AC = x when a galvanometer shows null deflection. If the radius of the bridge wire AB is doubled (keeping everything else the same), the new balance length AC will be:

Question

Accepted Answer

x. In a metre bridge, null deflection occurs when R1/R2 = AC/CB = x/(100-x). If the radius of the wire AB is doubled, the resistance per unit length decreases (R = rho*L/A, A increases by factor 4). But this decrease is the same for both portions AC and CB, so their ratio R_AC/R_CB = AC/CB remains unchanged. The null point position x is unaffected.

In a metre bridge experiment, the balance length AC = x when a galvanometer shows null deflection. If the radius of the bridge wire AB is doubled (keeping everything else the same), the new balance length AC will be:

Solution

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