A current of 2 A flows through a wire of cross-sectional area 25.0 mm². The number of free electrons in a cubic meter are 2.0 × 10²⁸. The drift velocity of the electrons is __________ × 10⁻⁶ m s⁻¹ (given, charge on electron = 1.6 × 10⁻¹⁹ C). Numerical answer type. Work it out, then open the answer.

Answer: 25. vd = I/neA, with A = 25 × 10⁻⁶ m² vd = 22 × 10²⁸ × 1.6 × 10⁻¹⁹ × 25 × 10⁻⁶ = 28 × 10⁴ vd = 2.5 × 10⁻⁵ = 25 × 10⁻⁶ m s⁻¹ Answer: 25

A current of 2 A flows through a wire of cross-sectional area 25.0… | JEE Main 2023 (8 Apr, Shift 1)

Q11JEE Main 2023 · 8 APR · SHIFT 1Easy

Electric Current, Drift Velocity & Current Density

A current of $2\text{ A}$ flows through a wire of cross-sectional area $25.0\text{ mm}^{2}$ . The number of free electrons in a cubic meter are $2.0 \times 10^{28}$ . The drift velocity of the electrons is __________ $\times 10^{-6}\text{ m s}^{-1}$ (given, charge on electron $= 1.6 \times 10^{-19}\text{ C}$ ).

Numerical answer type. Work it out, then open the answer.

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Answer: 25

$v_d = \dfrac{I}{neA}$ , with $A = 25 \times 10^{-6}\text{ m}^{2}$
$v_d = \dfrac{2}{2 \times 10^{28} \times 1.6 \times 10^{-19} \times 25 \times 10^{-6}} = \dfrac{2}{8 \times 10^{4}}$
$v_d = 2.5 \times 10^{-5} = 25 \times 10^{-6}\text{ m s}^{-1}$
Answer: 25

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