Question

Find equivalent resistance between A and B.

Answer 1

Answer:

This question can be solved by using Parallel Axis method.

Consider the parallel line XY dividing the circuit. We see that this axis acts parallel to AB and divides the circuit symmetrically.

Hence by this, we can say that the Potential at E and F is equal as well as Potential at C and D is also equal.

Hence resistors between E,F and between C,D can be removed. Hence the simplified circuit looks like the second image attached.

Using Parallel Combination, we get:

$\implies \dfrac{1}{R} = \dfrac{1}{5} + \dfrac{1}{1} + \dfrac{1}{5}\\\\\\\implies \dfrac{1}{R} = \dfrac{2}{5} + 1 \\\\\\\implies \dfrac{1}{R} = \dfrac{7}{5}\\\\\\\boxed{\implies R_{eff} = \dfrac{5}{7}}$

Hence the net resistance between A and B is 5/7 ohms.