If the potential energy of the electron is $-10 \ eV$,what is the total energy in $eV$?

The work function of sodium metal is $4.41 \times 10^{-19} \ J$. If photons of wavelength $300 \ nm$ are incident on the metal,the kinetic energy of the ejected electrons will be $\left( \dots \right) \times 10^{-21} \ J$. (Given: $h = 6.63 \times 10^{-34} \ J \cdot s; c = 3 \times 10^{8} \ m/s$)

The energy of an electron revolving in the $n^{th}$ Bohr's orbit of an atom is given by the expression

The energy of an electron in the first orbit of $He^{+}$ is $-871.6 \times 10^{-20} \ J$. What will be the energy of an electron in the first orbit of hydrogen?

If each hydrogen atom is excited by giving $8.4 \ eV$ of energy,then the number of spectral lines emitted is equal to :

When $\beta$-particles are sent through a tin metal foil,most of them go straight through the foil as