A) 32m
B) 64m
C) 16m
D) 8m
Correct Answer: A
Solution :
For \[{{Z}_{F}}\]distance ray optics is a good approximation. \[{{Z}_{F}}=\frac{{{a}^{2}}}{\lambda }\] Here, \[a=4\times {{10}^{-3}}m,\lambda =5\times {{10}^{-7}}\,m\] \[\therefore \] \[{{Z}_{f}}=\frac{16\times {{10}^{-6}}}{5\times {{10}^{-7}}}=32\,\,m\]You need to login to perform this action.
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