Question

The energy of hydrogen atom when the electron is in 3rd orbit is

• A. $-4.5\times {10}^{-19}J$
• B. $-2.42\times {10}^{-19}J$
• C. $-1.79\times {10}^{-19}J$
• D. $-3.2\times {10}^{-19}J$

Answer 1

The correct option is B $-2.42\times {10}^{-19}J$

$\text{Step 1: Energy of hydrogen atom}$

$E_n=-\frac{13.6}{n^2}eV$ $....\left(1\right)$

$\text{Step 2: Energy of hydrogen atom when electron is in 3rd orbit}$

Substitute $n=3$ in equation $\left(1\right)$

$\therefore E_3=-\frac{13.6}{3^2}eV=-1.51eV$

$=-1.51\times 1.602\times {10}^{-19}J$ $[\because 1eV=1.602\times {10}^{-19}J]$

$=-2.421\times {10}^{-19}J$

Hence, Option(B) is correct.

Formula used :