The velocity of charge carriers of current (about 1 ampere) in a metal under normal conditions is of the order of (a) a fraction of mm/sec (b) velocity of light (c) several thousand metres/second (d) a few hundred metres per second

Answer: (a). vd = I/neA; for copper n ≈ 10²⁹ m⁻³, A ≈ 10⁻⁶ m², I = 1 A vd ≈ 110²⁹ × 1.6 × 10⁻¹⁹ × 10⁻⁶ ≈ 10⁻⁴ m/s This is a fraction of a mm/s, so the answer is (a).

The velocity of charge carriers of current (about 1 ampere) in a… | NEET 1991 (AIPMT)

Q35NEET 1991 · AIPMTEasy

Electric Current, Drift Velocity & Current Density

The velocity of charge carriers of current (about 1 ampere) in a metal under normal conditions is of the order of

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Answer: (a)

$v_d = \dfrac{I}{neA}$ ; for copper $n \approx 10^{29}\text{ m}^{-3}$ , $A \approx 10^{-6}\text{ m}^{2}$ , $I = 1\text{ A}$
$v_d \approx \dfrac{1}{10^{29} \times 1.6 \times 10^{-19} \times 10^{-6}} \approx 10^{-4}\text{ m/s}$
This is a fraction of a mm/s, so the answer is (a).

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