A resistance of 2Ω is connected across one gap of a meter-bridge (the length of the wire is 100 cm ) and an unknown resistance, greater than 2Ω , is connected across the other gap. When these resistan

Question

A resistance of 2Ω is connected across one gap of a meter-bridge (the length of the wire is 100 cm ) and an unknown resistance, greater than 2Ω , is connected across the other gap. When these resistances are interchanged, the balance point shifts by 20 cm . Neglecting any corrections, the unknown resistance is

TestHub · Accepted Answer

∴ Applying ​ R 100 − x Q P ​ ​ > 2Ω > x = S R ​ ​ We have ​ R 2 ​ = 100 − x x ​ 2 R ​ = 80 − x x + 20 ​ ​ Solving Eqs. (i) and (ii), we get R = 3Ω ∴ Answer is (a).

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