The orientation of an atomic orbital is governed by

The energy of second Bohr orbit of the hydrogen atom is $$-$$328 kJ mol^$$-$$1; hence the energy of fourth Bohr orbit would be

The frequency of radiation emitted when the electron falls from n = 4 to n = 1 in hydrogen atom will be (Given ionization energy of H = 2.18 $$ \times $$ 10^$$-$$18 J atom^$$-$$1 and h = 6.625 $$ \times $$ 10^$$-$$34 J s)

The velocity of Planck's constant is 6.63 $$ \times $$ 10^$$-$$34 J s.

The velocity of light is 3.0 $$ \times $$ 10⁸ m s^$$-$$1. Which value is closest to the wavelength in nanometers of a quantum of light with frequency of 8 $$ \times $$ 10¹⁵ s^$$-$$1 ?