Question

An electron is at ground state of the H atom. Minimum energy required to excite the $H$ atom into second excited state is:

• A. $13.6eV$
• B. $12.1eV$
• C. $10.2eV$
• D. $3.4eV$

Answer 1

Answer: (B)

$12.1eV$

According to question, for an electron jump from first excited state to second
Energy required, $△E=E_3-E_1$
$=\frac{-13.6}{(3{)}^2}-(-13.6)$
$[\because$ Energy of excited $2nd$ excited state, $E_3=\frac{-13.6}{3^2}=\frac{-13.6}{9}]$
$\Rightarrow △E=-1.5+13.6=12.1eV$