BCECE Medical BCECE Medical Solved Papers-2002

  • question_answer
    The luminous efficiency of a lamp is 4 lumen/W and its luminous intensity is 30 Cd. The power of lamp is :

    A)  60 W          

    B)  78 W

    C)  94 W          

    D)  136 W

    Correct Answer: C

    Solution :

    In photometry luminous flux or luminous power is the measure of the perceived power of light. One lumen is defined as the luminous flux of light produced by a light source that emits one candela of luminous intensity over a solid angle of one steradian.                 \[F=4\pi I=4\times 3.14\times 30=377\] lumen Power of lamp \[=\frac{luminous\text{ }flux}{luminous\text{ }efficiency}\] \[=\frac{377}{4}\approx 94\,\,W\]


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