(a) Differentiate between electrical resistance and resistivity of a conductor.(b) Two metallic rods, each of length L, area of cross  and , having resistivities and are connected in parallel across a d.c. battery. Obtain the expression for the effective resistivity of this combination.

a) Electrical resistance (R) of a conductor equals the ratio of the potential difference (V) applied across it, to the resulting current (I) flowing through it.

b) The resistivity of a conductor equals the resistance of a wire of unit length and unit area of cross-section, drawn from the material of that conductor.

For the parallel combination equivalent resistance is given by

$\\\frac{1}{R}=\frac{1}{R_1}+\frac{1}{R_2}\\\\\frac{A_1+A_2}{\rho_{eq}L}=\frac{A_1}{\rho_1L}+\frac{A_2}{\rho_2L}$

$\rho_{eq}=\frac{\rho_1\rho_2(A_1+A_2)}{\rho_2A_1+\rho_1A_2}$

Related Chapters

Preparation Products

Knockout JEE Main April 2021 (One Month)

Personalized AI Tutor and Adaptive Time Table, Self Study Material, Weekend Live Classes, Mentorship from our Experts, Unlimited Mock Tests and Personalized Analysis Reports, 24x7 Doubt Chat Support,.

₹ 14000/- ₹ 4999/-
Knockout NEET Aug 2021 (One Month)

Personalized AI Tutor and Adaptive Time Table, Self Study Material, Weekend Live Classes, Mentorship from our Experts, Unlimited Mock Tests and Personalized Analysis Reports, 24x7 Doubt Chat Support,.

₹ 14000/- ₹ 4999/-
Knockout JEE Main May 2021

Personalized AI Tutor and Adaptive Time Table, Self Study Material, Weekend Live Classes, Mentorship from our Experts, Unlimited Mock Tests and Personalized Analysis Reports, 24x7 Doubt Chat Support,.

₹ 22999/- ₹ 9999/-
Knockout NEET Aug 2021

Personalized AI Tutor and Adaptive Time Table, Self Study Material, Weekend Live Classes, Mentorship from our Experts, Unlimited Mock Tests and Personalized Analysis Reports, 24x7 Doubt Chat Support,.

₹ 22999/- ₹ 9999/-