Q41 / 180 · NEET 2025 · Chemistry

The ratio of the wavelengths of the light absorbed by a Hydrogen atom when it undergoes $\mathrm{n}=2 \rightarrow \mathrm{n}=3$ and $\mathrm{n}=4 \rightarrow \mathrm{n}=6$ transitions, respectively, is

  • A
    $\frac{1}{36}$
  • B
    $\frac{1}{16}$
  • C
    $\frac{1}{9}$
  • Correct answer
    D
    $\frac{1}{4}$

Solution

$\frac{1}{\lambda}=\mathrm{RZ}^2\left(\frac{1}{\mathrm{n}_1^2}-\frac{1}{\mathrm{n}_2^2}\right)$ For $2 \rightarrow 3 \Rightarrow \frac{1}{\lambda_1}=\mathrm{R} \times(1)^2\left(\frac{1}{2^2}-\frac{1}{3^2}\right) \ldots(1)$ For $4 \rightarrow 6 \Rightarrow \frac{1}{\lambda_2}=\mathrm{R} \times(1)^2\left(\frac{1}{4^2}-\frac{1}{6^2}\right) \ldots(2)$ Divide (1) & (2) $\begin{aligned} & \frac{\lambda_2}{\lambda_1}=\frac{\frac{1}{2^2}-\frac{1}{3^2}}{\frac{1}{4^2}-\frac{1}{6^2}} \\ & \frac{\lambda_2}{\lambda_1}=\frac{4}{1} \\ & \therefore \frac{\lambda_1}{\lambda_2}=\frac{1}{4} \end{aligned}$

Hence, the correct answer is option: 'D'.

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