Optics Question 1135
Question: In Young’s double-slit experiment, an interference pattern is obtained on a screen by a light of wavelength $ 6000{AA} $ , coming from the coherent sources S1 and S2. At certain point P on the screen third dark fringe is formed. Then the path difference S1P ? S2P in microns is
[EAMCET 2003]
Options:
A) 0.75
B) 1.5
C) 3.0
D) 4.5
Show Answer
Answer:
Correct Answer: B
Solution:
For dark fringe at P $ S _{1}P-S _{2}P=\Delta =(2n-1)\lambda /2 $ .
Here n =3 and l = 6000 So, $ \Delta =\frac{5\lambda }{2}=5\times \frac{6000}{2}=15000{AA}=1.5\ micron $
