The wavelength of the first line of Paschen series is given by 1 / λ = R (1 / 3² - 1 / 4²).
Q1. The wavelength of the first line of Paschen series is given by 1 / λ = R (1 / 3² - 1 / 4²).
Answer: 18751 Å
Explanation: Substitute n1 = 3, n2 = 4, and R = 1.097 × 10⁷ m⁻¹ to get 1 / λ = 1.097 × 10⁷ (1/9 - 1/16) = 0.0533 × 10⁷, λ = 18751 Å.