A wire of resistance 10 Ω is bent to form a complete circle. The resistance between two diametrically opposite points would be-
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 2.5 Ω
The resistance of a uniform wire is proportional to its length. Two diametrically opposite points (A and C, or B and D) divide the circle into two equal semicircles, each of resistance 5 Ω. Between those points the two semicircles are in parallel.
\( \displaystyle \frac{1}{R} = \frac{1}{5\,\Omega} + \frac{1}{5\,\Omega} = \frac{2}{5\,\Omega} \)
\( \displaystyle R = 2.5\,\Omega \)