The energy required (in eV) to excite an electron of $\mathrm{H}$-atom from the ground state to the third…

The energy required (in eV) to excite an electron of $\mathrm{H}$-atom from the ground state to the third state is
  1. $+0.85$
  2. $-3.4$
  3. $12.1$
  4. $-12.1$

Solution

$E=\frac{-13.6 Z^2}{n^2}$ $E_1=\frac{-13.6 \times 1^2}{1^2}$ $=-13.6 \mathrm{eV}$ $E_2=\frac{-13.6 \times 1^2}{3^2}$ $=-1.5111 \mathrm{eV}$ $\therefore \quad \Delta E=E_2-E_1$ $\begin{aligned} & =-1.511-(-13.6) \\ & =12.08 \mathrm{eV} \\ & \cong 12.1 \mathrm{eV}\end{aligned}$

Asked in: AP EAMCET 2022 (05 Jul Shift 1)

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