Angular momentum of an electron in the $n^{th}$ orbit of a hydrogen atom is given by

The energy of the electron in the first orbit of $He^{+}$ is $-871.6 \times 10^{-20} \ J$. The energy of the electron in the first orbit of hydrogen would be

What will be the energy of an electron emitted from the ground state to the $n^{th}$ orbit?

In which one of the following pairs of experimental observations and phenomena does the experimental observation correctly account for the phenomenon?

Neon gas is generally used in sign boards. If it emits strongly at $616 \, nm$,calculate $(a)$ the frequency of emission,$(b)$ distance traveled by this radiation in $30 \, s$,$(c)$ energy of a quantum,and $(d)$ number of quanta present if it produces $2 \, J$ of energy.

Which of the following provisions of the Bohr atomic model of hydrogen turned out to be false?