Question

The wave number of infinite line in lyman series of hydrogen spectra is

Answer 1

Answer:

As,The last line in Lyman series is At infinity, using the formula (1/Lambda) = R( [1/{n1}^2] - [1/{n2}^2]). For the last line in lyman series, the electron will jump from first energy level to infinite level.

Answer 2

The wavenumber of infinite line in the Lyman series of hydrogen spectra is 109678 cm⁻¹.

• The wavenumber of a wave is the reciprocal of its wavelength i.e. k = 1/λ.

• For hydrogen spectra, 1/λ = R [ 1/n₂² - 1/n₁²]

• Here R is the Rydberg constant with the value 109678 cm⁻¹.
• n₁ and ₂ are the initial and the final shells of the electron respectively. For the Lyman series, n₂ = 1.
• For the infinite line, the electron must transit from the maximum possible shell. So n₁ = ∞.
• $\frac{1}{n_2^2} - \frac{1}{n_1^2} =$ 1/1² - 1/∞²

         = 1 - 0 = 1

      ⇒ 1/λ = k = R (1)

        = R = 109678 cm⁻¹