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In a metre bridge experiment null point is obtained at 40 ~cm from one end of the wire when resistance X is balanced against another resistance Y . If X < Y , then the new position of the null point from the same end, if one decides to balance a resistance of 3 X against Y , will be close to :

Options

  1. A80 ~cm
  2. B75 ~cm
  3. C67 ~cm
  4. D50 ~cm

Correct answer

C. 67 ~cm

Step-by-step solution

From question, x y = 40 100-40 = 2 3 x = 2 3 y Again, 3 x y = Z 100-Z or 3 2 y 3 y = Z 100-Z Solving we get Z =67 ~cm Therefore new position of null point 67 ~cm

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