The number of completely filled shells for the element ${ }_{16} S ^{32}$ is
$1$
$2$
$3$
$4$
Energy levels $A, B, C$ of a certain atom correspond to increasing values of energy i.e., $E_A < E_B < E_C$. If ${\lambda _1},{\lambda _2},{\lambda _3}$ are the wavelengths of radiation corresponding to the transition $C$ to $B, B$ to $A$ and $C$ to $A$ respectively, which of the following relation is correct ?
If the potential difference applied across $X-$ ray tube is $V$ volts, then approximately minimum wavelength of the emitted $X-$ rays will be
The ratio of ionization energy of Bohr's hydrogen atom and Bohr's hydrogen like lithium atom is
Explain Rutherford's explanation for scattered $\alpha $ -particles.
The diagram below shows the lowest four energy levels for an electron in a hypothetical atom.The electron is excited to the $-1\,eV$ level of the atom and transitions to the lowest energy state by emitting only two photons. Which of the following energies could not belong to either of the photons ? .....$eV$