For a hydrogen-like species,the ratio of velocities of electrons in the $I, II,$ and $III$ orbits,i.e.,$V_1 : V_2 : V_3$,will be:

Consider the following spectral lines for atomic hydrogen:
$A$. First line of Paschen series
$B$. Second line of Balmer series
$C$. Third line of Paschen series
$D$. Fourth line of Bracket series
The correct arrangement of the above lines in ascending order of energy is:

The spectral series formed when electrons of excited hydrogen atoms return to the third orbit from higher energy orbits is

Calculate the energy and frequency of the radiation emitted when an electron jumps from $n = 3$ to $n = 2$ in a hydrogen atom.

What is the difference between a photon and a quantum?

Typical electronic energy gaps in molecules are about $1.0 \ eV$. In terms of temperature,the gap is closest to