Question

Find the net resistance between a and b, all resistors being r

• A. 4r/3
• B. 3r/4
• C. r/4
• D. 4r

Answer 1

The correct option is A

4r/3

This circuit can be minimized as:

The effective resistance of the three parallel resistors is given by $\frac{1}{R}=\frac{1}{r}+\frac{1}{r}+\frac{1}{r}$
$\therefore R=\frac{r}{3}$
$\therefore$ Overall effective resistance $r+\frac{r}{3}=\frac{4r}{3}$