When 5V potential difference is applied across a wire of length 0.1 m, the drift speed of electron is 2.5 × 10–4 ms–1. If the electron density in the wire is 8 × 1028 m–3, the resistivity of the material is close to

Engineering

Physics

Ohm Law and Current Basics

Question

When 5V potential difference is applied across a wire of length 0.1 m, the drift speed of electron is 2.5 × 10^–4 ms^–1. If the electron density in the wire is 8 × 10²⁸ m^–3, the resistivity of the material is close to

1.6 × 10^–7 Ω-cm

1.6 × 10^–6 Ω-cm

1.6 × 10^–8 Ω-cm

1.6 × 10^–5 Ω-cm

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$V = {neAv}_{d} ρ \frac{ℓ}{A}$

$ρ = \frac{v}{{nev}_{d} ℓ}$

$= \frac{5}{8 \times 10^{28} \times 1 .6 \times 10^{- 19} \times 2 .5 \times 10^{- 4} \times 0 .1}$

$= \frac{5}{32} \times 10^{- 4} = 0.156 \times 10^{- 4} = 1.6 \times 10^{- 5}$