Question

Which among the following equations give the correct relation between Resistance(R), length of conductor(L), area of cross-section of the conductor(A) and resistivity $\left(\rho \right)$?

• A. $R=\frac{L}{A\times \rho }$
• B. $R=\frac{A\times \rho }{L}$
• C. $R=\frac{A\times L}{\rho }$
• D. $R=\frac{\rho \times L}{A}$

Answer 1

The correct option is D $R=\frac{\rho \times L}{A}$

Resistance of the conductor depends
(i) on its length,
(ii) on its area of cross-section, and
(iii) on the nature of its material.
Measurements have shown that resistance of a uniform metallic conductor is directly proportional to its length (L) and inversely proportional to the area of cross-section (A).
$R\alpha LR\alpha \frac{L}{A}R=\frac{\rho \times L}{A}$