Illumination Luminous efficiency of a fluorescence lamp is 70 lumens / watt. 60 lumens / watt. 40 lumens / watt. 30 lumens / watt. 70 lumens / watt. 60 lumens / watt. 40 lumens / watt. 30 lumens / watt. ANSWER DOWNLOAD EXAMIANS APP
Illumination What is the ratio of illuminance at a point 5m just below a lamp emitting 100 candelas and at a point 5m away from the first point on the same horizontal plane? 1: 2√2 2:1 1:2 2√2 : 1 1: 2√2 2:1 1:2 2√2 : 1 ANSWER DOWNLOAD EXAMIANS APP
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 30 %. 20 %. 45 %. 70 %. 30 %. 20 %. 45 %. 70 %. ANSWER DOWNLOAD EXAMIANS APP
Illumination Which cells in the eye are responsible for scotopic vision? None of these Rod cells Cone cells Both ‘a’ and ‘b’ None of these Rod cells Cone cells Both ‘a’ and ‘b’ ANSWER DOWNLOAD EXAMIANS APP
Illumination From a uniform light source having luminous intensity of 300 candelas, there exists a plane surface 15 m below. The value of illuminance at a point on the plane surface where the luminous flux rays are inclined at an angle of 30 to the surface is 1.53 lux. 58.45 Kilolux. 1.15 lux. 17.32 lux. 1.53 lux. 58.45 Kilolux. 1.15 lux. 17.32 lux. 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? 6 2 4 5 6 2 4 5 ANSWER DOWNLOAD EXAMIANS APP
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