JEE Main & Advanced Physics Wave Optics / तरंग प्रकाशिकी Question Bank Critical Thinking

  • question_answer
    In Young's double slit experiment, the intensity on the screen at a point where path difference is l is K. What will be the intensity at the point where path difference is \[\lambda /4\] [RPET 1996]

    A)            \[\frac{K}{4}\]                     

    B)            \[\frac{K}{2}\]

    C)            K    

    D)            Zero

    Correct Answer: B

    Solution :

               By using phase difference \[\varphi =\frac{2\pi }{\lambda }(\Delta )\] For path differencel, phase difference \[{{\varphi }_{1}}=2\pi \]and for path difference l/4, phase difference f2 = p/2. Also by using \[I=4{{I}_{0}}{{\cos }^{2}}\frac{\varphi }{2}\]  Þ \[\frac{{{I}_{1}}}{{{I}_{2}}}=\frac{{{\cos }^{2}}({{\varphi }_{1}}/2)}{{{\cos }^{2}}({{\varphi }_{2}}/2)}\]  Þ \[\frac{K}{{{I}_{2}}}=\frac{{{\cos }^{2}}(2\pi /2)}{{{\cos }^{2}}\left( \frac{\pi /2}{2} \right)}=\frac{1}{1/2}\] Þ \[{{I}_{2}}=\frac{K}{2}.\]


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