List of top Physics Questions on atom structure models

If hydrogen atom, an electron jumps from bigger orbit to smaller orbit so that radius of smaller orbit is one-fourth of radius of bigger orbit. If speed of electron in bigger orbit was \(v\), then speed in smaller orbit is:
Arrange the following in the increasing order of their basic strengths: $CH_{3}NH_{2}$, $(CH_{3})_{2}NH$, $(CH_{3})_{3}N$ and $NH_{3}$
If an electron drops from $n=4$ to $n=2$ in a hydrogen atom, the series of spectral lines observed is: