In Wheatstone's bridge `P = 9 ohm`, `Q = 11 ohm`, `R = 4 ohm` and `S = 6 ohm`. How much resistance must be put in parallel to the resistance `S` to balance the bridge

Options

A. `24 ohm`
B. `(44)/(9) ohm`
C. `26.4 ohm`
D. `18.7 ohm`

Answer

C

Explanation

(c ) `(P)/(Q) = (R )/(S')` (For balancing bridge)
`implies S' = (4 xx 11)/(9) = (44)/(9)`
`implies (1)/(S') = (1)/(r ) + (1)/(6)`
`implies (9)/(44) - (1)/(6) + (1)/(r )`
`implies r = (132)/(5) = 26.4 Omega`