JEE Main & Advanced Physics Wave Optics / तरंग प्रकाशिकी Question Bank Mock Test - Wave Optics

  • question_answer
    In a YDSE bichromatic lights of wavelengths 400 nm and 560 nm are used. The distance between the slits is 0.1 mm and the distance between the plane of the slits and the screen is 1 m. The minimum distance between two successive regions of complete darkness is

    A) 4 mm   

    B) 5.6 mm

    C) 14 mm 

    D) 28 mm

    Correct Answer: D

    Solution :

    [d] Let nth minima of 400 nm coincides with nth minima of 560 nm then \[(2n-1)400=(2m-1)560\Rightarrow \frac{2n-1}{2m-1}=\frac{7}{5}=\frac{14}{10}=\frac{21}{15}\]i.e., 4th minima of 400 nm coincides with 3rd minima of 560 nm. The location of this minima is \[=\frac{21(1000)(4000\times {{10}^{-6}})}{2\times 0.1}=42mm\] \[\therefore \]Required distance=28mm


You need to login to perform this action.
You will be redirected in 3 sec spinner