P and Q are two points on a uniform ring of resistance R. O is the centre of the ring. If ∠ POQ = π rad, the equivalent resistance of the ring between the points P and Q will be _.

Question

Accepted Answer

(4) R/4. Given: a uniform ring of total resistance R; ∠ POQ = π, so P and Q are the two ends of a diameter. Idea: the two arcs between P and Q are in parallel, and the resistance of each arc is proportional to its length. Each semicircle has resistance R/2. R_PQ = ((R/2)(R/2))/(R/2 + R/2) = R/4. So the equivalent resistance between P and Q is R/4.

P and Q are two points on a uniform ring of resistance R. O is the centre of the ring. If ∠ POQ = π rad, the equivalent resistance of the ring between the points P and Q will be _______.

Step-by-step solution

Why the other options are wrong