When is Hα line in the emission spectrum of hydrogen atom obtained?

Energy of an electron in the nth orbit hydrogen atom is given by , En = -13.6/n² eV
Hα line in the emission spectrum of hydrogen atom is obtained in 3→2 transition.
Frequency of photon obtained in the transition is given by:
ΔE = hf = -13.6(1/9 - 1/4) eV
ΔE = 13.6 × 5/36 × 1.6 × 10⁻¹⁹ J
f = ΔE/h = 13.6 × 5 × 1.6 × 10⁻¹⁹ / (36 × 6.6 × 10⁻³⁴)
f = 4.57 × 10¹⁴ Hz