Question

if the diameter of a wire is trippled then what will be it's resistance and resistivity???​

Answer 1

Answer:

R = p. 1/A

(a) I → 3l

R’ = P. 3 l/A = 3 R

Resistance gets tripled,

(b) d → 3d

R = p. I/A = R = P. 1/ πr2 = P.1/π(d/2)2

R’ = P. I/π (3d/2)2 = (1/9)p. I/π(d/2)2 = R/9

Resistance becomes 1/9 th.

(c) R = P. I/A

P → 3P

R’ = 3p. I/A = 3R

Resistance becomes 3 times.