The unknown resistances are connected in two gaps of a metre bridge. The null point is at 20 ~cm from zero end. A resistance of 15 is connected in series with the smaller of the two. The null point shifts to 40 ~cm . The smaller resistance

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The unknown resistances are connected in two gaps of a metre bridge. The null point is at 20 ~cm from zero end. A resistance of 15 is connected in series with the smaller of the two. The null point shifts to 40 ~cm . The smaller resistance is

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Correct answer: A. 9

20 80 = r₁ r₂ = 1 4 4 r₁=r₂ 40 60 = r₁+15 r₂ = 2 3 (r₁+15 ) 3=2 r₂=2 4 r₁=8 r₁3 r ₁+45=8 r ₁5 r ₁=45 r ₁=9

The unknown resistances are connected in two gaps of a metre bridge. The null point is at 20 ~cm from zero end. A resistance of 15 is connected in series with the smaller of the two. The null point shifts to 40 ~cm . The smaller resistance is

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