A circular coil of single turn has a resistance of 20 Ω. Which one of the following is the correct value for the resistance between the ends of any diameter of the coil?
5 Ω
10 Ω
20 Ω
40 Ω
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC NDA-1 – 2017
Let the total resistance of the circular coil be R. The resistance of each semicircle is R/2. When these two semicircles are connected in parallel, the equivalent resistance (R_eq) is given by the formula for resistors in parallel: 1/R_eq = 1/R₁ + 1/R₂. Here, R₁ = R₂ = R/2.
So, 1/R_eq = 1/(R/2) + 1/(R/2) = 2/R + 2/R = 4/R.
Therefore, R_eq = R/4.