Question

The energy of an electron in the first Bohr's orbit of a hydrogen atom is $2.18\times {10}^{-18}J$. Its energy in the second orbit will be:

• A. $-1.09\times {10}^{-18}J$
• B. $-4.36\times {10}^{-18}J$
• C. $-5.45\times {10}^{-19}J$
• D. $-8.72\times {10}^{-18}J$

Answer 1

The correct option is C $-5.45\times {10}^{-19}J$

Energy of an electron is given by,

$E_n=\frac{-13.6}{n^2}eV$, for hydrogen Z=1

For Bohr's second orbit n=2

Therefore, $E_2=-3.4eV$ but $1eV=1.6\times {10}^{-19}J$

$E_2=-5.45\times {10}^{-19}J$