Vikas TU
Last Activity: 4 Years ago
Wire of resistance R is elongated n fold to make a new uniform wire.So its radius is reduced by n times.
Let l and r be the original length and radius of the original wire.So,
Original Resistance of the wire , R = ρl/πr^2
Now radius is reduced by n times ,so new radius is r' = r/n
New resistance,R' = ρl/πr'^2 = ρl/π(r/n)^2
= n^2ρl/πr^2 = n^2R