Illumination A 1000 W bulb fitted with a reflector illuminates an area of 3 m x 3 m with an average illumination of 450 lux. If the bulb has and efficiency of 9 lumens / watt the efficiency of the reflector is 45 %. 30 %. 20 %. 70 %. 45 %. 30 %. 20 %. 70 %. ANSWER DOWNLOAD EXAMIANS APP
Illumination Luminous efficiency of a fluorescence lamp is 40 lumens / watt. 30 lumens / watt. 70 lumens / watt. 60 lumens / watt. 40 lumens / watt. 30 lumens / watt. 70 lumens / watt. 60 lumens / watt. ANSWER DOWNLOAD EXAMIANS APP
Illumination The illumination at a point 5 meters below a lamp in 6 lux. The candle power of the lamp is 200. 150. 140. 30 200. 150. 140. 30 ANSWER DOWNLOAD EXAMIANS APP
Illumination A 200 candle power lamp is hung 4 m above the centre of circular area of 5 m diameter. The illumination at centre of the area is 12.5 lux. 17.5 lux. 18.5 lux. 13.5 lux. 12.5 lux. 17.5 lux. 18.5 lux. 13.5 lux. ANSWER DOWNLOAD EXAMIANS APP
Illumination The illumination of the surface varies directly with cosine of the angle between normal to surface and direction of the inclined light is given by Lambert’s cosine law. both A and B. None of these law of square inverse. Lambert’s cosine law. both A and B. None of these law of square inverse. ANSWER DOWNLOAD EXAMIANS APP
Illumination What will be the number of lamps, each having 300 lumens, required to obtain an average illuminance of 50 lux on a 4m × 3m rectangular room? 4 6 2 5 4 6 2 5 ANSWER DOWNLOAD EXAMIANS APP
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