Question

A wire of resistance 20 ohm is stretched to 3 times of its length and then cut in 3 equal parts to form an equilateral triangle.Find the equivalent resistance between any 2 corners of this triangle.

Answer 1

i think 60 ohm is the right answer

Answer 2

R = ρL/A

Since volume remains constant.

V = L*A

L' = 3L then A' = A/3

R' = ρL'/A' = 9R = 180 Ω

So, we divide it into 3 resistors of 60 Ω each.

So, we have 2 resistors of 60 Ω in series parallel to 1 resistor of 60 Ω.

On solving, the answer is 40 Ω.