Question

The equivalent resistance between A and B in the circuit will be

• A. $\frac{5}{4}r$
• B. $\frac{6}{5}r$
• C. $\frac{7}{6}r$
• D. $\frac{8}{7}r$

Answer 1

The correct option is D $\frac{8}{7}r$

In the circuit, by means of symmetry the point C is at zero potential. So the equivalent circuit can be drawn as

$R_{eq}=(\frac{8r}{3}\parallel 2r)=\frac{8}{7}r$