Question

A hydrogen atom, initially in the ground state is excited by absorbing a photon of wavelength 980$\mathring A$. The radius of the atom in the excited state, it terms of Bohr radius $a_0$, will be : ($h_c$ = $12500\, eV - \mathring A$)

• A. $9a_0$
• B. $25a_0$
• C. $4a_0$
• D. $16a_0$

Answer 1

Answer: (D)

$16a_0$

Answer 2

The correct answer is (D) : $16a_0$
Energy of photon $= \frac{12500}{980} = 12.75 eV$
$\therefore$ Electron will excite to $n = 4$
Since $'R' \propto n^2$
$\therefore$ Radius of atom will be $16a_0$