In a Young's double slit experiment with light of wavelength $\lambda$, fringe pattern on the screen has fringe width $\beta$. When two thin transparent glass (refractive index $\mu$ ) plates of thickness $t_1$ and $t_2$ $\left(t_1>t_2\right)$ are placed in the path of the two beams respectively, the fringe pattern will shift by a distance

• A

  $\frac{\beta(\mu-1}{\lambda}\left(\frac{t_1}{t_2}\right)$
• B

  $\frac{\mu \beta}{\lambda} \frac{t_1}{t_2}$
• Correct answer
  C

  $\frac{\beta(\mu-1}{\lambda}\left(t_1-t_2\right.$
• D

  $\left(\mu-1 \frac{\lambda}{\beta}\right)\left(t_1+t_2 \quad\right)$

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