Question

a wise of resistance 20 ohm is bent in a closed Square. what is the resistance across a diagonal of the square

Answer 1

Resistance of each side is 5 ohm as resistance is directly proportional to length then along diagonal it is parallel combination of two resistors 10 ohm each. So equivalent resistance is 10 ohm.

Answer 2

To make a square of the wire we bend it so that it has 4 sides. Then each side has resistance 5 ohm (as the total resistance of the wire is 20 ohm).

If we draw one diagonal of the square, then combining the resistance of the two sides the either two sides of the diagonal the resultant resistance is 10 ohm on both sides of the diagonal.

If diagonal was to open up into two parts then calculating resistance in parallel we get 5 ohm.

So the total resistance across the ends of the diagonal is 5 ohm.

Final answer : 5 ohm