What is the wave number of a photon emitted during the transition from orbit $n=4$ to $n=2$ in a hydrogen atom (in $cm^{-1}$)? $[R_{H}=109677 \ cm^{-1}]$

What is the difference between a photon and a quantum?

The space between the proton and the electron in a hydrogen atom is:

The radius of the second Bohr orbit is $x$. The de-Broglie wavelength of an electron in the $4^{th}$ orbit is nearly

The number of absorption lines in the given figure will be .......

For a hydrogen $(H)$ atom,what will be the wavelength (in $nm$) associated with the transition of an electron from the infinite energy level to the first energy level? (Rydberg constant = $1.097 \times 10^{7} \ m^{-1}$)