Question

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 1

The value 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/66.3

After 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 Ω

putting the value of s in the first eqn

r = s x 33.7/66.3

=> r = 13.47 x 33.7/66.3

=> r = 6.84Ω

Hence the value of r and s are 6.84Ω and 13.47 Ω respectively.

Answer 2

Answer:

Explanation:

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