JEE Main & Advanced Physics Ray Optics Question Bank Critical Thinking

  • question_answer
    A small plane mirror placed at the centre of a spherical screen of radius R. A beam of light is falling on the mirror. If the mirror makes n revolution. per second, the speed of light on the screen after reflection from the mirror will be

    A)            4pnR                                        

    B)            2pnR

    C)            \[\frac{nR}{2\pi }\]            

    D)            \[\frac{nR}{4\pi }\]

    Correct Answer: A

    Solution :

               When plane mirror rotates through an angle q, the reflected ray rotates through an angle 2q. So spot on the screen will make 2n revolution per second.


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