For He⁺, a transition takes place from the orbit of radius 105.8 pm to the orbit of radius 26.45 pm. The wavelength (in nm) of the emitted photon is ___. [Use: Bohr radius a = 52.9 pm; Rydberg constant R_H = 2.2 × 10⁻¹⁸ J; Planck’s constant h = 6.6 × 10⁻³⁴ J s; speed of light c = 3 × 10⁸ m s⁻¹.]