NEET Chemistry — Structure of Atom

The ionization energy of $\text{Li}^{2+}$ is $122.4 \, \text{eV}$. What is the energy required to excite an electron from $n = 3$ to $n = 6$? ($1 \, \text{eV} = 1.6 \times 10^{-19} \, \text{J}$)

The energy of an electron in the first orbit of a hydrogen atom is $-2.18 \times 10^{-18} \, \text{J}$. What is the wavelength of the photon emitted when an electron in $\text{Be}^{3+}$ transitions from $n = 6$ to $n = 3$? ($h = 6.626 \times 10^{-34} \, \text{J s}$, $c = 3.0 \times 10^8 \, \text{m s}^{-1}$)

Which of the following transitions in a hydrogen atom emits light of the shortest wavelength?

The work function of a metal is $2.0 \, \text{eV}$. What is the maximum kinetic energy of an electron ejected by light of wavelength $400 \, \text{nm}$? ($h = 6.626 \times 10^{-34} \, \text{J s}$, $c = 3.0 \times 10^8 \, \text{m s}^{-1}$, $1 \, \text{eV} = 1.6 \times 10^{-19} \, \text{J}$)

The ratio of the angular momentum of an electron in the third orbit of $\text{H}$ to the second orbit of $\text{He}^+$ is: ($h = 6.626 \times 10^{-34} \, \text{J s}$)