Question

A circuit consists of five identical conductors as shown in figure. The two similar conductors are added as indicated by the dotted lines. The ratio of resistances before and after addition will be

• A. $\frac{7}{5}$
• B. $\frac{3}{5}$
• C. $\frac{5}{3}$
• D. $\frac{6}{5}$

Answer 1

Answer: (C)

$\frac{5}{3}$

Answer 2

Before adding, resistances 5 ohms After, the central one is a Wheatstone?s network $\therefore$ Total resistance is 1+(2 & 2 in parallel) $+1=3\,\Omega$ $\therefore$ The ratio o f resistances $=5/3$