In a Wheatstone bridge network `P and Q` the ratio area are approximately equal. When `R = 500 Omega`, the bridge is balanced on interchange `P and Q` the value of `R` for balance is `505 Omega`. Find the value of `S` and ratio `P : Q`

Answer

`(1)/(1.005)`

Explanation

As bridge balace so
`(P)/(Q) = (R )/(S) = (500)/(S)` ….(i) On interchanging P and Q the balnced condition in given us
`(Q)/(P) = (R')/(S) = (505)/(S)`
Multiplying (i) and (ii) we get
`(P)/(Q) xx (Q)/(P) = (500)/(S) xx (505)/(S) or I = (500 xx 505)/(S^(2))`
or `S = [500 xx 505]^(1//2) = 502.5 Omega`
Putting this value of `S` in (i) we get
`(P)/(Q) = (505)/(502//5) = (1)/(1.005)`