Question

What length of a certain metal wire of diameter 0.15 mm is needed for the wire to have a resistance of 15 ?? The resistivity of this metal is 1.68

Answer 1

let it be L

Now, we have,

ρL/a = R
So,

15 = [1.68 x 10^-8 x L /(π x 0.075²) ] 10⁶

So, 15 = 0.95068 x L

So, L = 15.77 m = 16m

c.16 m