Question

As the electron in Bohr's orbit of hydrogen atom passes from state $n=2$ to, $n=1$, the kinetic energy$\left(K\right)$ and the potential energy $\left(U\right)$ changes as

• A. K four fold, U also four fold
• B. K two fold, V also two fold
• C. K four fold, U two fold
• D. K two fold, U four fold

Answer 1

The correct option is A K four fold, U also four fold

Given,

Electron in Bohr's orbit of hydrogen atom passes from state $n=2$ to $n=1$,

KE of an electron in nth orbit : $K_n\propto \frac{1}{n^2}$ and PE of an electron in nth orbit : $U_n\propto \frac{1}{n^2}$
$\therefore$ When an electron passes from state n = 2 to n = 1
$\frac{K_2}{K_1}=\frac{1^2}{2^2}=\frac{1}{4}$
or $K_1=4K_2$
$\frac{U_2}{U_1}=\frac{1^2}{2^2}=\frac{1}{4}$
or $U_1=4U_2$