Line spectrum contains information about

The spectrum obtained from a sodium vapour lamp 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.

Ionisation energy of $Li$ (Lithium) atom in ground state is $5.4 \ eV$. Binding energy of an electron in $Li^+$ ion in ground state is $75.6 \ eV$. Energy required to remove all three electrons of Lithium $(Li)$ atom is ........... $eV$.

During a total solar eclipse,the Fraunhofer lines become clearly visible because...

$A$ photon collides with a stationary hydrogen atom in the ground state inelastically. The energy of the colliding photon is $10.2 \ eV$. After a time interval of the order of a microsecond,another photon collides with the same hydrogen atom inelastically with an energy of $15 \ eV$. What will be observed by the detector?