In the case of a hydrogen atom,when an electron falls from a higher energy level to the $M$ shell,the corresponding spectral line will form a part of:

Rutherford created a theoretical picture of the atom based on :

The electron in the hydrogen atom undergoes a transition from higher orbitals to an orbital of radius $211.6 \text{ pm}$. This transition is associated with:

The energy associated with the first orbit of $He^{+}$ is

In Rutherford's experiment,generally the thin foil of heavy atoms,like gold,platinum etc. have been used to be bombarded by the $\alpha$-particles. If the thin foil of light atoms like aluminium etc. is used,what difference would be observed from the above results?

The ionization energy of sodium in $kJ \ mol^{-1}$,if electromagnetic radiation of wavelength $242 \ nm$ is just sufficient to ionize a sodium atom,is . . . . . . .