The spectrum obtained from a sodium vapour lamp is an example of

The wavelength of the emission line spectrum and the absorption line spectrum of a substance are related as:

The splitting of a spectral line into groups under the effect of an electric or magnetic field is called:

The spectrum of iodine gas under white light will be:

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 ............. $nm$.

$A$ 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?