JEE Main202624 January 2026Evening ShiftChemistryStructure of AtomActual
The wavelength of spectral line obtained in the spectrum of Li ²⁺ ion, when the transition takes place between two levels whose sum is 4 and difference is 2, is
Options
- A1.14 10⁻⁷ ~cm
- B1.14 10⁻⁶ ~cm
- C2.28 10⁻⁷ ~cm
- D2.28 10⁻⁶ ~cm
Correct answer
B. 1.14 10⁻⁶ ~cm
Step-by-step solution
For Li²⁺ (Z=3): From n₂ + n₁ = 4 and n₂ - n₁ = 2 , we get n₂ = 3 , n₁ = 1 Using Bohr wavelength formula: 1 = RZ^2 ( 1 n₁^2 - 1 n₂^2 ) 1 = 1.097 10^7 9 (1 - 1 9 ) = 9.873 10^7 8 9 1 = 8.776 10^7 m⁻¹ = 1.14 10⁻⁶ cm