Hello,

Bohr’s quantization condition of angular momentum: According to Bohr electron can revolve in certain discrete orbits called stationary orbits.

For Brackett series n1 = 4 and n2 = 5 6 7… Therefore For shortest wavelength n2 = ∞. Therefore or λ 1458.5 10-9 m or 1458.5 nm.The shortest wavelength of the Brackett series is 1458.5 nm. This wavelength belongs to infrared range of electromagnetic spectrum.

Thank you.