Emission transitions in the Panchen series end at orbit n = 3 and start from orbit n and can be represented as v = 3.29 × 1015 (Hz) [1/32 – 1/n2]

Calculate the value of n if the transition is observed at 1285 nm. Find the region of the spectrum.

Given:

Wavelength, λ = 1285 nm


Frequency, v = 3.29 × 1015 [1/32 – 1/n2] (Hz)


Speed of Light = [Frequency] × [Wavelength]


We know speed of light = 3×108 m/s


Frequency, v = [3×108] / [1285 × 10-9]


v = 2.3346×1014 Hz


3.29 × 1015 [1/32 – 1/n2] = 2.3346×1014


[1/32 – 1/n2] = [2.3346×1014] / [3.29 × 1015]


[1/32 – 1/n2] = 0.07427


[1/9] – 0.07427 = 1/n2


1/n2 = 0.04


1/n2 = 1 / 25


n2 = 25


n = 5


The value of n is 5.


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