A) 15
B) 17
C) 8
D) 16
Correct Answer: B
Solution :
For principal maxima in grating spectra \[\frac{\sin \theta }{N}=n\lambda \] where, \[n=(1,\,\,2,\,\,3)\] is the order of principal maxima and \[\theta \] is the angle of diffraction. \[n=\frac{1}{\lambda N}=\frac{1}{6.25\times {{10}^{-7}}\times 2\times {{10}^{5}}}=8\] \[\therefore \] Number of maxima \[=2n+1=2\times 8+1=17\]You need to login to perform this action.
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