A wavelength of 656.3 nm is emitted by the hydrogen atoms in a high-voltage discharge tube. What are the initial and final values of the quantum number n for the energy level transition that produces this wavelength?

Answer : The initial and final values of the quantum number is, 2 and 3

Explanation :

Assumption : We have to determine the value of wavelength when electron will jump from 2 to 3 level.

Using Rydberg's Equation:

Where,

= Wavelength

= Rydberg's Constant  =

= Higher energy level = 3

= Lower energy level = 2

Putting the values, in above equation, we get

From this we conclude that the calculated value of wavelength is equal to given value of wavelength.

Therefore, the initial and final values of the quantum number is, 2 and 3

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