In a single-slit diffraction experiment, the slit is illuminated by light of two wavelength $\lambda_1$ and $\lambda_2$. It is observed that the 2 nd order diffraction minimum for $\lambda_1$ coincides with the 3 rd diffraction minimum for $\lambda_2$. Then

• A

  $\frac{\lambda_1}{\lambda_2}=\frac{2}{3}$
• B

  $\frac{\lambda_1}{\lambda_2}=\frac{5}{7}$
• Correct answer
  C

  $\frac{\lambda_1}{\lambda_2}=\frac{3}{2}$
• D

  $\frac{\lambda_1}{\lambda_2}=\frac{7}{5}$

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