Question

two wires of same material and same length have radii 1 mm and 2mm respectively compare their i.)resistance ii.) specific resistancex​

Answer 1

Answer:

$R= \rho l/A$

Since materials are same, so $\rho$ is same for both the wires.

So,

$\frac{R_1}{R_2}=\frac{l_1A_2}{l_2A1}=\frac{l_1r_2^2}{l_2r_1^2}$

(i)  Since their lengths are same, only radius matters

$\frac{R_1}{R_2}=\frac{l*1^2}{l*2^2}=\frac{1}{4}$

(ii) specific resistance ($\rho$, also knows as resistivity) depends only upon the materials of the wire. Since they are made of the same material, the specific resistance is same for both the wires.