JEE Mains · Physics · STD 12 - 3. current electricity
When \(5\ V\) potential difference is applied across a wire of length \(0.1\ m\), the drift speed of electrons is \(2.5 \times 10^{-4}\) \(ms^{-1}\) . If the electron density in the wire is \(8 \times 10^{28}\) \(m^{-3}\) the resistivity of the material is close to
- A \(1.6 \times 10^{-7} \) \(Ω m\)
- B \(1.6 \times 10^{-5} \) \(Ω m\)
- C \(1.6 \times 10^{-3} \) \(Ωm\)
- D \(1.6 \times 10^{-8} \) \(Ωm\)
Answer & Solution
Correct Answer
(B) \(1.6 \times 10^{-5} \) \(Ω m\)
Step-by-step Solution
Detailed explanation
\(V=I R=\left(n e A v_{d}\right) \rho \frac{\ell}{A}\) \(\therefore \quad \rho=\frac{\mathrm{V}}{\mathrm{V}_{\mathrm{d}} \mathrm{lne}}\) Here \(\mathrm{V}=\) potential difference \(\mathrm{I}=\) length of wire \(\mathrm{n}=\mathrm{no} .\) of electrons per unit volume of…
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