Optics Question 459
Question: In the Young’s double slit experiment, if the phase difference between the two waves interfering at a point is $ \phi $ , the intensity at that point can be expressed by the expression
Options:
A) $ I=\sqrt{A^{2}+B^{2}{{\cos }^{2}}\varphi } $
B) $ I=\frac{A}{B}\cos \varphi $
C) $ I=A+B\cos \frac{\varphi }{2} $
D) $ I=A+B\cos $
Show Answer
Answer:
Correct Answer: D
Solution:
[d] $ I=a _{1}^{2}+a _{2}^{2}+2a _{1}a _{2}\cos \varphi $
Put $ a _{1}^{2}+a _{2}^{2}=A $ and $ a _{1}a _{2}=B $
$ \therefore I=A+B\cos \varphi $
