Answer:
[tex]t = 0.192 \mu m[/tex]
Explanation:
Path difference due to a transparent slab is given as
[tex]\Delta x = (\mu - 1) t[/tex]
here we know that
[tex]\mu = 1.79[/tex]
now total shift in the bright fringe is given as
[tex]Shift = \frac{D(\mu - 1)t}{d}[/tex]
Also we know that the fringe width of maximum intensity is given as
[tex]\delta x = \frac{\lambda D}{d}[/tex]
now we have
[tex]\frac{D}{d} = \frac{\delta x}{\lambda}[/tex]
now the shift is given as
[tex]Shift = \frac{(\mu - 1) t \delta x}{\lambda}[/tex]
given that the shift is
[tex]Shift = 0.37 \delta x[/tex]
here we have
[tex]0.37 \delta x = \frac{(\mu - 1) t \delta x}{\lambda}[/tex]
now plug in all values in it
[tex]0.37 = \frac{(1.79 - 1) t}{411 \times 10^{-9}}[/tex]
[tex]t = 0.192 \times 10^{-6} m[/tex]
[tex]t = 0.192 \mu m[/tex]