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CBSE Class 12 · 2016 · All India · Modern PhysicsShort Answer

Calculate the wavelength of the radiation emitted when the electron in a hydrogen atom jumps from

n = \infty

to

n = 1

.

Answer: $λ \approx 91.2 nm$ (Lyman series limit).

Solution

Using the Rydberg formula (

R = 1.097 \times 1 0^{7} m^{- 1}

):

\frac{1}{λ} = R (\frac{1}{1 ^{2}} - \frac{1}{\infty ^{2}}) = R .

λ = \frac{1}{R} = \frac{1}{1.097 \times 1 0 ^{7}} \approx 9.11 \times 1 0^{- 8} m = 91.1 nm .

λ \approx 91.2 nm (series limit of the Lyman series)

CBSE Class 12 Board · 2016 · All India · Subjective

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