The ionization energy of an electron in an excited state of a hydrogen atom is $+0.85 \, eV$. What will be the energy of the emitted photon in $eV$ when it returns to the ground state?

Which of the following equations represents the velocity $(v)$ of the ejected electrons when a metal is struck with light of frequency $\nu$ and the threshold frequency of the metal is $\nu_0$? ($m_e =$ mass of electron and $h$ is Planck's constant).

The values of Planck's constant and the speed of light are $6.63 \times 10^{-34} \ J \ s$ and $3.0 \times 10^8 \ m \ s^{-1}$ respectively. Find the approximate wavelength in nanometers $(nm)$ of a light ray with a frequency of $8 \times 10^{15} \ s^{-1}$.

If the wave number of radiation emitted for the electron transition from an excited state $n_2$ to the first excited state $(n_1 = 2)$ of a hydrogen atom is $\frac{5x}{36} \ m^{-1}$, the wave number of radiation absorbed for the electron transition from the same excited state $n_2$ to the next immediate higher excited state $(n_3 = n_2 + 1)$ in $m^{-1}$ is:

The ionization energy of $He^+$ is $19.6 \times 10^{-18} \ J \ atom^{-1}$. What is the energy of the first stationary state $(n = 1)$ of $Li^{2+}$?

Which of the following series of transitions in the spectrum of hydrogen atom falls in the visible region?