What is the amount of energy associated with the first orbit of a monopositive helium ion? $[R_{H} = 2.18 \times 10^{-18} \ J]$

For a lithium atom,what can be said about the angular momentum and energy values for the permitted orbit of its third electron?

Electrons with a kinetic energy of $6.023 \times 10^4 \ J/mol$ are evolved from the surface of a metal when it is exposed to radiation of wavelength $600 \ nm$. The minimum amount of energy required to remove an electron from the metal atom is

The light of wavelength $242 \, nm$ is required to remove an electron from a $Na$ atom. What is the ionization energy of the sodium atom in $kJ \, mol^{-1}$?

Explain the phenomenon of black body radiation.

Write the postulates of Bohr's model of the hydrogen atom.