Emission transitions in the Paschen series end at orbit n = 3 and start from orbit n and can be represented as v = 3.29 x 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, ν = (3.29 x 1015 Hz) (1/32 – 1/n2)= (3.29 x 1015 Hz) (1/32 – 1/n2) (3 x 108 ms-1) / (1.285 x 10-6 m) = (3.29 x 1015 Hz) (1/32 – 1/n2)2.3346 x 1014 = (3.29 x 1015 Hz) (1/32 – 1/n2)2.3346 / 32.9 = 1/32 – 1/n20.071 = 1/9 – 1/n21/n2 = 1/9 – 0.071= 0.111 – 0.071 = 0.04n2 = 1/ 0.04 = 25=> n = 5For n = 5, Paschen series lies in infrared region of the spectrum.

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Ncert Solutions Chemistry Class 11th Chemistry Class 11th Structure of Atoms

Emission transitions in the Paschen series end at orbit n = 3 and start from orbit n and can be represented as v = 3.29 x 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.

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alok kumar singh | Contributor-Level 10

3 months ago

Given, ν = (3.29 x 10¹⁵ Hz) (1/3² – 1/n²)

= (3.29 x 10¹⁵ Hz) (1/3² – 1/n²)

(3 x 10⁸ ms^-1) / (1.285 x 10^-6 m) = (3.29 x 10¹⁵ Hz) (1/3² – 1/n²)

2.3346 x 10¹⁴ = (3.29 x 10¹⁵ Hz) (1/3² – 1/n²)

2.3346 / 32.9 = 1/3² – 1/n²

0.071 = 1/9 – 1/n²

1/n²= 1/9 – 0.071= 0.111 – 0.071 = 0.04

n²= 1/ 0.04 = 25

=> n = 5

For n = 5, Paschen series lies in infrared region of the spectrum.

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