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JEE Main & Advanced Physics Ray Optics Question Bank Photometry

  • question_answer
    A point source of 100 candela is held 5m above a sheet of blotting paper which reflects 75% of light incident upon it. The illuminance of blotting paper is

    A)            4 phot                                     

    B)            4 lux

    C)            3 phot                                     

    D)            3 lux

    Correct Answer: B

    Solution :

               \[I=\frac{L}{{{r}^{2}}}=\frac{100}{{{5}^{2}}}\]=4 Lux.


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