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12. atoms — Physics STD 12 Science — Question

CBSE BoardEnglish MediumSTD 12 SciencePhysics12. atoms1 Mark
MCQ
For hydrogen atom, $\lambda_1$ and $\lambda_2$ are the wavelengths corresponding to the transitions $1$ and $2$ respectively as shown in figure. The ratio of $\lambda_1$ and $\lambda_2$ is $\frac{x}{32}$. The value of $x$ is $..........$
  • ✓
    $27$
  • B
    $26$
  • C
    $25$
  • D
    $24$
✓

Answer

Correct option: A.
$27$
a
$\frac{1}{\lambda}= Rz ^2\left[\frac{1}{ n _1^2}-\frac{1}{ n _2^2}\right]$

$\frac{1}{\lambda_1}= Rz ^2\left[\frac{1}{1^2}-\frac{1}{3^2}\right]=\frac{8}{9} Rz ^2$

$\frac{1}{\lambda_2}= Rz ^2\left[\frac{1}{1^2}-\frac{1}{2^2}\right]=\frac{3}{4} Rz ^2$

$1 / 2 \Rightarrow \frac{\lambda_2}{\lambda_1}=\frac{8}{9} \times \frac{4}{3}=\frac{32}{27}$

$\frac{\lambda_1}{\lambda_2}=\frac{27}{32}$

Ans.$27$

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