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Question
A wire of uniform cross-section and resistance 4 ohms is bent in the shape of square ABCD. Point A is connected to point P on DC by a wire AP of resistance 1 ohm. When a potential difference is applied between A and C, the points B and P are seen to be at the same potential. What is the resistance of the part DP?
Solution
As the points B and P are at the same potential, `1/1 = (((1 + x))/((2 + x)))/((1 - x))` ⇒ x = `(sqrt2 - 1)` ohm
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