MCQ
In Bohr’s model of atom when an electron jumps from $n =1$ to $n=3,$ how much energy will be absorbed
  • A
    $2.15 \times 10^{-10} \, ergs$
  • $0.1911  \times 10^{-10} \, ergs$
  • C
    $2.389  \times 10^{-10} \, ergs$
  • D
    $0.239 \times 10^{-10} \, ergs$

Answer

Correct option: B.
$0.1911  \times 10^{-10} \, ergs$
b
Energy of an atom when $n=1$

$E_{1}=-\frac{1312}{(1)^{2}}=-1312 \mathrm{kJ} \mathrm{mol}^{-1}$

Similarly energy when $n=3,\left(E_{3}\right)$

$=-\frac{1312}{(3)^{2}}$

$=-145.7 \mathrm{kJ} \mathrm{mol}^{-1}$

The energy absorbed when an electron jumps from $n=1$ to $n=3$

$E_{3}-E_{1}=-145.7-(-1312)=1166.3 \mathrm{kJ} \mathrm{mol}^{-1}$

$=\frac{1166.3}{6.023 \times 10^{23}}=193.6 \times 10^{-23} \mathrm{kJ}$

$=193.6 \times 10^{-20} \mathrm{J}\left[1\right.$ Joule $\left.=10^{7} \mathrm{ergs}\right]$

$\Rightarrow 193.6 \times 10^{-13}$ ergs $=0.1936 \times 10^{-10} \mathrm{ergs}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free