Question

The energy required to excite an electron in hydrogen atom to its first excited state is

• A. 8.5 eV
• B. 10.2 Ev
• C. 12.7 eV
• D. 13.6 eV

Answer 1

Answer: (B)

10.2 Ev

Answer 2

Energy, $E_{n} = - \frac{13.6}{n^{2}}eV$

In ground state energy $E_{1} = \frac{13.6}{1^{2}} = - 13.6eV$

In first excited state energy $E_{2} = \frac{13.6}{2^{2}} = - 3.4eV$

Then the required energy $= E_{2} - E_{1}$

$= - 3.4 - ( - 13.6) = 10.2eV$