A wire of resistance 10 ohm is bent in the form of a closed circle . What is the effective resistance between the points at the ends of any diameter of a circle ?
it is 2.5 ohms as
the resistance of straight wire = 10 ohm
when it is bent in the form of a closed circle, the wires will be connected in parallel. Also, the length will be half, so resistance will also become half,
so resisteance of each part connected in parallel will be 5 ohms.
Now, resistance in parallel combination, 1/R = 1/R1 + 1/R2
1/R=1/5 + 1/5