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MHT CET · Physics · Wave Optics

In biprism experiment, if \(5^{\text {th }}\) bright band with wavelength \(\lambda_1\) coincides with \(6^{\text {th }}\) dark band with wavelength \(\lambda_2\) then the ratio \(\left(\lambda_1 / \lambda_2\right)\) is

  1. A \(\frac{7}{9}\)
  2. B \(\frac{10}{11}\)
  3. C \(\frac{11}{10}\)
  4. D \(\frac{9}{7}\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(\frac{11}{10}\)

Step-by-step Solution

Detailed explanation

\(\begin{aligned} & \text { Given: } y_5=y_6^{\prime} \\ & \left(\frac{\mathrm{n} \lambda \mathrm{D}}{\mathrm{d}}\right)_5=\left[\frac{(2 \mathrm{n}-1) \lambda \mathrm{D}}{2 \mathrm{~d}}\right]_6 \\ & \frac{5 \lambda_1 \mathrm{D}}{\mathrm{d}}=\frac{11 \lambda_2 \mathrm{D}}{2 \mathrm{~d}}\end{aligned}\)
\(\therefore \quad \frac{\lambda_1}{\lambda_2}=\frac{11}{10}\)