Optics Question 1111
Question: In Young’s experiment, the distance between slits is 0.28 mm and distance between slits and screen is 1.4 m. Distance between central bright fringe and third bright fringe is 0.9 cm. What is the wavelength of used light
[KCET 1999]
Options:
A) $ 5000{AA} $
B) $ 6000{AA} $
C) $ 7000{AA} $
D) $ 9000{AA} $
Show Answer
Answer:
Correct Answer: B
Solution:
Position of 3rd bright fringe $ x _{3}=\frac{3D\lambda }{d} $
$ \Rightarrow \lambda =\frac{x _{3}d}{3D}=\frac{(0.9\times {{10}^{-2}})\times (0.28\times {{10}^{-3}})}{3\times 1.4}=6000{AA} $
