Four resistances of `16 Omega , 12 Omega , 4 Omega and 9 Omega` respectively are connected in cycle order so from a Wheatstone bridge. Calculate the resistance in be connected in parallel with `9 Omega` resistance to balance the bridge.

Options

A. `13.5Omega`
B. `15.5Omega`
C. `27Omega`
D. `12Omega`

Answer

A

Explanation

To balance the bridge equivalent resistance of `R_(4)` and shunt x should be `9 Omega`
`:.R_(P)=(R_(4)xx x)/(R_(4)+ x)`
`9=(27 xx x)/(27 + x) :.x=13.5Omega`.