Current Electricity - Result Question 110

115. In a metre-bridge, the balancing length from the left end when standard resistance of 1Ω is in right gap is found to be 20cm. The value of unknown resistance is

[1999]

(a) 0.25Ω

(b) 0.4Ω

(c) 0.5Ω

(d) 4Ω

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Answer:

Correct Answer: 115. (a)

Solution:

  1. (a) Let unknown resistance be X. Then condition of Wheatstone’s bridge gives XR=20r80r, where r is resistance of wire per cm.

X=2080×R=14×1=0.25Ω



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