The solar spectrum is an example of

Consider the following two statements $A$ and $B$ and identify the correct choice in the given answers:
$A :$ Line spectra are due to atoms in the gaseous state.
$B :$ Band spectra are due to molecules.

In the absorption spectrum of $Na$,the missing wavelength$(s)$ are:

$A$ stationary hydrogen atom emits a photon corresponding to the first line of the Lyman series. The recoil velocity of the atom is nearly (in $m/s$)

The nature of the sun's spectrum is

In a Franck-Hertz experiment,an electron of energy $5.6 \ eV$ passes through mercury vapour and emerges with an energy $0.7 \ eV$. The minimum wavelength of photons emitted by mercury atoms is close to ............. $nm$.