Question

A conductor of resistance $3 \, \Omega$ is stretched uniformly till its length is doubled. The wire is now bent in the form of an equilateral triangle. The effective resistance between the ends of any side of the triangle in ohms is

• A. $\frac{9}{2}$
• B. $\frac{8}{3}$
• C. $2$
• D. $1$

Answer 1

Answer: (B)

$R=3\Omega$
When stretched $R^{′}=4\times 3=12 \, \Omega$
Therefore each side of the triangle has resistance $4 \, \Omega$

$R_{A B}=\frac{8 \times 4}{8 + 4}=\frac{32}{12}=\frac{8}{3}\Omega$