Question

Four resistances 4Ω, 4Ω, 4Ω and 12Ω form a Wheatstone's network. Find the resistance which when connected across the 12Ω resistance will balance the network.

Answer 1

Given: P = Q = R = 4Ω

Let resistance connected across 12Ω be X.

Equivalent resistance for 12Ω and X in parallel is given by

`X^'=(12xxX)/(12+X)`

`X^' = S=(12X)/(12+X)`

From formula,

`4/4= (4/(12X))/(12+X)`

`1 = (4 (12 + X))/(12X)`

`12X = 48+4X`

`X = 6 Ω`