Question

A wire of length l is drawn such that its diameter is reduced to half its orginal diameter. if the initial resistance of the wire were 10 ohm, its resistance would be

a) 40 ohm
b) 60 ohm
c) 120 ohm
d) 160 ohm​

Answer 1

Basically the idea is that the radius is = the diameter ^2 / 4
If we factor the 1/4 and multiply by 4 on both sides we get 40 ohms

Lmk if it’s wrong