A) 10
B) 20
C) 45
D) 90
E) 35
Correct Answer: D
Solution :
Using red light\[(\lambda =6600{\AA})\]60 fringes are seen. Hence, range of field of view is \[60\times w=60\times \frac{D\lambda }{d}\] using light of wavelength\[\lambda ,n\]fringes are seen, then \[\Rightarrow \] \[60\times \frac{D\lambda }{d}=n\times \frac{D\lambda }{d}\] \[60\times \lambda =n\times \lambda \] \[\Rightarrow \] \[n=60\times \frac{\lambda }{\lambda }=60\times \frac{6600}{4400}=90\]You need to login to perform this action.
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