question_answer

Taking the wavelength of first Balmer line in hydrogen spectrum (n = 3 to n = 2) as 660 nm, the wavelength of the 2nd Balmer line (n = 4 to n = 2) will be: [JEE Main 9-4-2019 Morning]

A) 889.2 nm

B) 642.7 nm

C) 488.9 nm

D) 388.9 nm

Correct Answer: C

Solution :

[c]                    ....(1)

....(2)

divide equation (1) with (2)

Option