

A given length of a wire is doubled on itself and this process is repeated once again. By what factor does the resistance of the wire change?
Let the resistance of the wire be R.
When the wire is doubled on itself and the process is repeated then -
The length of the wire reduces by 1/2, and the area increases by 2 times.
Thus, the resistance of the wire reduced by 1/4 times.
So, resistance = R/4
So, the total resistance of the wire when the resistors are arranged in parallel,
1/Rp = 1/(R/4) + 1/(R/4) + 1/(R/4) + 1/(R/4)
Rp = R/16
Thus, the resistance of the wire reduces by 16 times.
