Current Electricity

JEE Main level, numerical answer, medium

342 of 380

Question 342 of 380

In the given figure of meter bridge experiment, the balancing length ACAC corresponding to null deflection of the galvanometer is 40cm40cm. The balancing length, if the radius of the wire ABAB is doubled, will be _____ cmcm.

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Answer: 40

Even if the radius of wire is doubled, the balancing point would not change asxl−x=R1R2\dfrac{x}{l-x}=\dfrac{{R}_{1}}{{R}_{2}} , which is independent of area in case of uniform wire. Thus, the balancing length remains the same i.e., 40cm40cm.

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