Which of the following spectra contains all frequencies from the high to the low frequency range?

The band spectra (characteristic of molecular species) is due to emission of radiation from which state of matter?

The wavelength of a photon emitted by a stationary helium atom is $0.1 \ \mathring{A}$. What is the recoil energy of the atom in $eV$?

$A$ hydrogen atom emits a photon corresponding to an electron transition from $n = 5$ to $n = 1$. The recoil speed of the hydrogen atom is almost......$m/s$ (mass of proton $\approx 1.6 \times 10^{-27} \ kg$).

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

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