Physics - Modern Physics Question with Solution | TestHub

The speed of an electron in a hydrogen atom is given by $V=2.18\times 10^6\frac{Z}{n}$ m/s,

where $Z$ is the atomic number and $n$ is the principal quantum number.

For a hydrogen atom, $Z=1$, so $V\propto \frac{1}{n}$.

Therefore, as $n$ increases, $V$ decreases, inversely proportional to $n$. The curve that represents this relationship is option A.