engineering physics MCQ #467

The wavelength of a spectral line is given by 1 / λ = R (1 / n1² - 1 / n2²). For the first line of Lyman series, n1 = 1 and n2 = 2.

engineering physics MCQ #467

  1. Question 1

    Q1. The wavelength of a spectral line is given by 1 / λ = R (1 / n1² - 1 / n2²). For the first line of Lyman series, n1 = 1 and n2 = 2.

    • A) 1216 Å
    • B) 1026 Å
    • C) 6563 Å
    • D) 4341 Å

    Answer: 1216 Å

    Explanation: Substitute n1 = 1, n2 = 2, and R = 1.097 × 10⁷ m⁻¹ to get 1 / λ = 1.097 × 10⁷ (1 - 1/4) = 0.82275 × 10⁷, λ = 1216 Å.