If $a$0 is denoted as the Bohr radius of hydrogen atom, then what is the de-Broglie wavelength (λ) of the electron present in the second orbit of hydrogen atom? [n : any integer]
Solution
<p>Bohr radius of hychogon atom $\rightarrow a_0$</p>
<p>According to Bohr, the equation used to calculate the angular momentum of an election in a hydrogen atom is</p>
<p>$\mathrm{mvr=\frac{nh}{2\pi}}$ ..... (1)</p>
<p>$m \rightarrow$ mass of electron</p>
<p>$v \rightarrow$ velocity of electron</p>
<p>$r \rightarrow$ radius of the orbit</p>
<p>$n \rightarrow$ orbit. number. in. which electron is present.</p>
<p>Given that; election is present in second orbit, $n=2$</p>
<p>The radius of the second orbit $r_2=a_0\times2^2=4a_0$</p>
<p>General formula for radius of $n^{th}$ orbit,</p>
<p>$r_n=a_0\times n^2$</p>
<p>From (1)</p>
<p>$$\begin{aligned}
& m v r=n \frac{h}{2 \pi} \\
& 2 \pi r=n \frac{h}{m v}
\end{aligned}$$</p>
<p>$\frac{h}{m v}=\lambda$ (de Broglie relation ship, $\lambda \rightarrow$ de Broglie Wavelength</p>
<p>So, $2 \pi r=n \lambda$</p>
<p>For the electron in the second orbit, $2 \pi r_2=n \lambda$</p>
<p>Substitute for $r_2$,</p>
<p>$$\begin{aligned}
& 2 \pi \times 4 a_0=n \lambda \\
& 8 \pi a_0=n \lambda \\
& \therefore \lambda=\frac{8 \pi a_0}{n}
\end{aligned}$$</p>
<p>Correct answer: Option 1) $\frac{8 \pi a_0}{n}$</p>
About this question
Subject: Chemistry · Chapter: Atomic Structure · Topic: Bohr's Model
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