2021 Current ElectricityDrift of Electrons and the Origin of Resistivity Medium Question 37 of 130 in Current Electricity

Column-I gives certain physical terms associated with flow of current through a metallic conductor. Column-II gives some mathematical relations involving electrical quantities. Match Column-I and Column-II with appropriate relations.

Column I

  • A. Drift Velocity
  • B. Electrical Resistivity
  • C. Relaxation Period
  • D. Current Density

Column II

  • P. $\frac{m}{ne^2\rho}$
  • Q. $nev_d$
  • R. $\frac{eE}{m}\tau$
  • S. $\frac{E}{J}$

Correct answer: A → R, B → S, C → P, D → Q

Solution

Drift velocity: $v_d = \left(\frac{eE}{m}\right)\tau$ Resistivity: $J = \sigma E = \frac{E}{\rho} \Rightarrow \rho = \frac{E}{J}$ Relaxation period: $\rho = \frac{E}{nev_d}$ and $v_d = \frac{eE}{m}\tau$ give $\tau = \frac{m}{ne^2\rho}$ Current density: $i = neAv_d \Rightarrow J = \frac{i}{A} = nev_d$ Correct match: A-R, B-S, C-P, D-Q.

Concept drift velocity, resistivity, relaxation time and current density

Current Electricity in past papers

130 questions from this chapter have appeared across 27 exam years.