Question

When we observe the light emitted by a collection of atoms of a gas by passing it though a prism (spectroscope), we can separate out photons of different wavelengths to view the spectrum of a gas. A continuous spectrum of light of all wavelengths resembles a rainbow. What would the emission spectrum of gas of atoms with quantized energy levels look like?

Answer 1

Atomic spectra will be discontinuous spectra means there will be little or no continuum emission and it will only display light at specific wavelengths.

we know that electrons can absorb and emit only specific, discrete energies

we know that electrons cannot stay excited and will eventually return back to stable level/state and while returning back, they release energy in the form of light ( photon).  Photons have different energies corresponding to different wavelengths.