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

$A$ neutron moving with a speed $v$ makes a head-on collision with a stationary hydrogen atom in its ground state. The minimum kinetic energy of the neutron for which an inelastic collision will take place is....$eV$

Given below are two statements:
Statement $I$: Atoms are electrically neutral as they contain equal number of positive and negative charges.
Statement $II$: Atoms of each element are stable and emit their characteristic spectrum.
In the light of the above statements,choose the most appropriate answer from the options given below.

An electron of a stationary hydrogen atom transitions from the fifth energy level to the ground level. The velocity that the atom acquires as a result of photon emission will be:

$A$ 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?

Band spectrum is produced by