If shortest wavelength of hydrogen atom in Lyman series is x, then longest wavelength in Balmer series of He+ is:
- 9x5
- 36x5
- x4
- 5x9
Answer
(1) 9x5
Solution
For a one-electron species: 1 = RZ2 ( 1n12- 1n22 )
Shortest wavelength of Lyman series of H (Z = 1): n1 = 1, n2 =
⇒ 1x = R ( 112-0 ) = R ⇒ R = 1x
Longest wavelength of Balmer series of He+ (Z = 2): n1 = 2, n2 = 3
⇒ 1 = R(2)2 ( 122- 132 )
⇒ 1 = 4R 536 = 5R9
∴ = 95R = 9x5
Answer: (1)