A copper wire of length 10 m and radius (10⁻²√(π)) m has electrical resistance of 10 Ω. The current density in the wire for an electric field strength of 10 (V/m) is (a) 104 A/m2 (b) 106 A/m2 (c) 10 - 5 A/m2 (d) 105 A/m2

Answer: (d). Area A = π r² = π × 10⁻⁴π = 10⁻⁴ m² Resistivity ρ = RA/l = 10 × 10⁻⁴10 = 10⁻⁴ Ω m J = E/ρ = 1010⁻⁴ = 10⁵ A/m² So the answer is (d).

A copper wire of length 10 m and radius (10⁻²√(π)) m has electrical… | NEET 2022 (Phase 1)

Q15NEET 2022 · PHASE 1Easy

Electric Current, Drift Velocity & Current Density

A copper wire of length 10 m and radius $\left(\frac{10^{-2}}{\sqrt{\pi}}\right)$ m has electrical resistance of 10 $\Omega$ . The current density in the wire for an electric field strength of 10 (V/m) is

Show answer and solution

Answer: (d)

Area $A = \pi r^{2} = \pi \times \dfrac{10^{-4}}{\pi} = 10^{-4}\text{ m}^{2}$
Resistivity $\rho = \dfrac{RA}{l} = \dfrac{10 \times 10^{-4}}{10} = 10^{-4}\ \Omega\text{ m}$
$J = \dfrac{E}{\rho} = \dfrac{10}{10^{-4}} = 10^{5}\text{ A/m}^{2}$
So the answer is (d).

Report a mistake

Electric Current, Drift Velocity & Current Density question from NEET 2022 (Phase 1)

More questions on Electric Current, Drift Velocity & Current Density