The equivalent resistance of the circuit shown below between points a and b is :

Step-by-step solution

The resistance in a b is parallel to all other resistances. Since all the resistances other than R b is 4   Ω the potential is zero V x = V y as the upper branch will become a case of balanced wheatstone bridge between V x & V y . So, the simplified circuit looks like the one below. Hence, the equivalent resistance is 1 R e q = 1 8 + 1 8 + 1 16 = 5 16 ⇒ R e q = 16 5   Ω = 3 . 2   Ω