Question

A wire of resistance R ohm is doubled on it. Calculate the new resistance

Answer 1

Answer:

By doubleing the wire you are in effect breaking out into two 2ohm resistances. Then you are placing them in parallel. So the resulting resistance is one ohm.

Note that the English term doubled on itself denotes folding in two and not stretching so many answers here which assume stretching are incorrect. If the terms of the question change this will affect the answer.