A) \[2.945\times {{10}^{-7}}m\]
B) \[3.945\times {{10}^{-7}}m\]
C) \[4.95\times {{10}^{-7}}m\]
D) \[1.945\times {{10}^{-7}}m\]
Correct Answer: A
Solution :
If thin film appears dark 2mt cos r = nl for normal incidence \[r={{0}^{o}}\] Þ 2 m t = nl Þ \[t=\frac{n\lambda }{2\mu }\] Þ \[{{t}_{\min }}=\frac{\lambda }{2\mu }\]= \[\frac{5890\times {{10}^{-10}}}{2\times 1}\]\[=2.945\times {{10}^{-7}}m\].
You need to login to perform this action.
You will be redirected in
3 sec
