Question

What is the energy of an electron in stationary state corresponding to $n=2$ ?

• A. $-3.45 \times 10^{-18} J$
• B. $-0.545 \times 10^{-18} J$
• C. $0.545 \times 10^{-18} J$
• D. $3.45 \times 10^{-18} J$

Answer 1

Answer: (B)

Energy of an electron is given by
$E_n=\frac{-13.6}{n^2} eV$
For $n=2$
$E=\frac{-13.6}{2 \times 2} eV =\frac{-13.6}{4} eV $
$ {\left[1 eV =1.602 \times 10^{-19} J \right]} $
$ =-3.4 \times 1.602 \times 10^{-19} J $
$ =-5.45 \times 10^{-19} J $
$ \text { or }=-0.545 \times 10^{-18} J $