Question

In meter bridge experiment, A thin uniform wire AB of length 1 m and unknown resistance x and a resistance of 12Ω are connected. In the above question, after appropriate conditions are made, it is found that no deflection takes places in the galvanometer when the sliding jockey touches the wire at a distance of 60 cm from A. What is the value of the resistance X ? 

(A) 18Ω 

(B) 8Ω 

(C) 16Ω 

(D) 4Ω

Answer 1

The correct option is (B) 8Ω.

Explanation:

No deflection in the galvanometer means wheatstone's bridge is balanced. distance of jockey from point A = R_AE = 60 cm 

Total length is 100 cm hence R_BE = 40 cm 

∴ (x / 12) = (R_BE / R_AE) 

∴ (x / 12) = (40 / 60) 

∴ x = 8Ω