Get Answers to all your Questions

header-bg qa

(a) Differentiate between electrical resistance and resistivity of a conductor.

(b) Two metallic rods, each of length L, area of cross A_{1} and A_{2} , having resistivities \rho_{1} and \rho_{2} are connected in parallel across a d.c. battery. Obtain the expression for the effective resistivity of this combination.

 

Answers (1)

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}

Posted by

Safeer PP

View full answer

Crack CUET with india's "Best Teachers"

  • HD Video Lectures
  • Unlimited Mock Tests
  • Faculty Support
cuet_ads