Optics Question 1070
Question: Two coherent light sources S1 and S2 (l= 6000 Å) are 1mm apart from each other. The screen is placed at a distance of 25 cm from the sources. The width of the fringes on the screen should be
[CPMT 1990]
Options:
A) 0.015 cm
B) 0.025 cm
C) 0.010 cm
D) 0.030 cm
Show Answer
Answer:
Correct Answer: A
Solution:
$ \beta =\frac{6000\times {{10}^{-10}}\times 25\times {{10}^{-2}}}{{{10}^{-3}}} $
$ \therefore {\lambda _{glass}}<{\lambda _{air}}\ \ (\because \ C _{glass}<C _{air}) $ .
