Biography, Science, Technology, Health, History Blogs

10 Question-answer on photometry 1.        Inverse square law for illuminance is valid for (a)     Isotropic point-source (b)    Cylindrical source (c)     Search light (d)    All type of sources Ans: (a) 2.        The luminous intensity of 100 W unidirectional bulb is 100 candela. The total luminous flux emitted from bulb will be: (a)     100 π lumen (b)    200 π lumen (c)     300 π lumen (d)    400 π lumen Ans: (d) 3.        A lamp of 250 candle power is hanging at a distance of 6 m from a wall. The luminance at a point on the wall. The illuminance at a point on the wall at a minimum distance from lamp will be: (a)     9.64 lux (b)    9.69 lux (c)     6.94 lux (d)    None of these Ans: (c) 4.    ...