In standard Young's double-slit experiment, visible light $\mathrm{\lambda }\in \left(350nm\text{, }750nm\right)$ is used in both the slits. Distance between the slits is $2 \mathrm{mm}$, and the distance of the screen from the slits is $1 \mathrm{m}$. A thin glass slab $\left(\mu =\text{1.5}\right)$ of thickness $6 \mathrm{\mu }\text{m}$ is placed in front of slit ${\mathrm{S}}_2$. Which among the following wavelengths is missing at point $\mathrm{P,}$ which is directly in front of slit ${\mathrm{S}}_2$?(Neglect dispersion of light)


           

• Correct answer
  A

  $400 \mathrm{nm}$
• B

  $500 \mathrm{nm}$
• C

  $600 \mathrm{nm}$
• D

  $700 \mathrm{nm}$

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