Question

For the first two lines of Paschen series, identify the value of n1 and n2.
Calculate the wave number values for these lines.

Answer 1

In Paschen series the elctrons fall back to n₁ = 3.

First line n₁ = 3 , n₂= 4

We should use Rydberg equation to calculate wave number value:

ν = R*(1/n₁² - 1/ n₂²)

v = 1.09678*10⁷ (1/3² - 1/4²) = 5.331*10⁵ m^-1

Second line n₁ = 3 , n₂ = 5

v = R*(1/n₁² - 1/ n₂²)

v = 1.09678*10⁷ (1/3² - 1/5²) = 7.799*10⁵ m^-1