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In a meter bridge the null point is found at a distance of 33.7c.M from a of the wire. If now a resistance of 12 ohm is connected in parallel with s the null point occurs at 51.9c.M determine the values of r and s. |
| Answer» UE of r and s are 6.84Ω and 13.47 Ω respectively.Explanation : From the 1st balance point we get,r/s = 33.7/66.3=> r = 33.7s/66.3After 12Ω resistance is added in parallel with s, EQUIVALENT resistance will become,s₁ = s||12=> s₁ = 12S/(12+s)From the 2nd balance point,r/s₁ = 51.9/48.1=> r = s₁ x 51.9/48.1=> r = 12s/(12+s) x 51.9/48.1=> 33.7s/66.3 = 12s/(12+s) x 51.9/48.1=> 12 + s = (12 x 51.9 x 66.3)/(33.7 x 48.1)=> 12 + s = 25.47=> s = 13.47 Ωputting the value of s in the FIRST eqnr = s x 33.7/66.3=> r = 13.47 x 33.7/66.3=> r = 6.84ΩHence the value of r and s are 6.84Ω and 13.47 Ω respectively. | |