Question

As the electron of a Hydrogen atom passes from state $n=2$ to $n=1$, the kinetic energy $\left(K\right)$ and potential energy $\left(U\right)$ become -

• A. $K$ two-fold, $U$ four-fold
• B. $K$ four-fold, $U$
• C. $K$ and $U$ both four-fold
• D. $K$ and $U$ both two-fold

Answer 1

The correct option is C $K$ and $U$ both four-fold

We know that,

$K\propto \frac{Z^2}{n^2}$ and $U\propto \frac{Z^2}{n^2}$

So,

$K_{n=2}\propto \frac{Z^2}{4}$ and $U_{n=2}\propto \frac{Z^2}{4}$

$K_{n=1}\propto Z^2$ and $U_{n=1}\propto Z^2$

Therefore, both $K$ and $U$ become four-fold.

Hence, option $\left(C\right)$ is the correct answer.