engineering physics MCQ #996

The drift velocity of electrons in a wire is 1 mm/s. If the current is 2 A, what is the number of free electrons per unit volume?

engineering physics MCQ #996

  1. Question 1

    Q1. The drift velocity of electrons in a wire is 1 mm/s. If the current is 2 A, what is the number of free electrons per unit volume?

    • A) 1.25 * 10²⁸ /m³
    • B) 2.5 * 10²⁸ /m³
    • C) 1.25 * 10²⁹ /m³
    • D) 2.5 * 10²⁹ /m³

    Answer: 1.25 * 10²⁸ /m³

    Explanation: I = nAvd*e, rearranging gives n = I / (Avd*e), substituting values gives n = 1.25 * 10²⁸ /m³.