Q 12-03-244JEE MainJEE Main 2019 (10 Jan, Shift 1)Easy
A uniform metallic wire has a resistance of $18\ \Omega$ and is bent into an equilateral triangle. Then, the resistance between any two vertices of the triangle is:
Answer: (D) $4\ \Omega$
Each side is $6\ \Omega$. Between two vertices one side ($6\ \Omega$) is in parallel with the other two in series ($12\ \Omega$):
$$R = \frac{6\times12}{6+12} = 4\ \Omega$$
Solution by Sreeraj P, M.Sc Physics