The wavelength of the first line of Paschen series is given by 1 / λ = R (1/9 - 1/16).
Q1. The wavelength of the first line of Paschen series is given by 1 / λ = R (1/9 - 1/16).
Answer: 1875 nm
Explanation: 1 / λ = R (1/9 - 1/16) = 7R / 144, λ = 144 / (7R) = 1875 nm.