Of the following pairs of species,which one will have the same electronic configuration for both members?

$A$ 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?

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

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.

Which of the following atoms has the lowest ionization potential?

Match the following:

$1$. Burning candle	$i$. Line spectrum
$2$. Sodium vapour	$ii$. Continuous spectrum
$3$. Bunsen flame	$iii$. Band spectrum
$4$. Dark lines in solar spectrum	$iv$. Absorption spectrum