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In case of installations in commercial buildings, evenly distributed lights can be obtained by the use of lenses, which reduces ____________.
decoration
brightness
colour
spot light
brightness
Evenly distributed lighting in commercial buildings is achieved by using lenses or diffusers that spread the luminous flux. This process significantly reduces excessive glare and localized high brightness (hotspots) from bare light sources.
IS 3646: Part 1 - 1992
Evenly distributed lighting in commercial buildings is achieved by using lenses or diffusers that spread the luminous flux. This process significantly reduces excessive glare and localized high brightness (hotspots) from bare light sources.
E=d2IтЛЕcos(╬╕)тАЛ тАФ where E is the illuminance, I is the luminous intensity, and d is the distance.
╬ж=тИлтИлI(╬╕,╧Х)sin(╬╕)d╬╕d╧Х тАФ representing the total luminous flux distributed.
Lenses utilize the principle of refraction to control the light distribution pattern. By bending light rays away from the central axis or spreading them across a wider angle, the luminous intensity per unit area is lowered at any single point, leading to a more uniform luminance distribution across the illuminated surface.
Uniformity in lighting is essential to prevent eye fatigue and improve visual comfort.
Glare is often caused by high brightness contrast between a light source and its surroundings.
Optical lenses are specifically designed to manipulate the beam angle of luminaires.
Enhanced visual comfort for occupants
Reduction in reflected glare on screens and surfaces
Better light utilization efficiency
Increased manufacturing cost of luminaires
Possible light absorption losses within the lens material
Commercial office spaces
Retail display lighting
Task lighting environments
Brightness is the visual perception of luminance (L). Reduction of glare directly correlates to the control of luminance.
Option A (decoration) is unrelated to the functional lighting distribution. Option C (colour) depends on the source spectrum, not the lens geometry. Option D (spot light) is a type of luminaire, not a characteristic to be reduced by lenses.
B is correct тАФ Lenses reduce localized brightness and glare to ensure uniform illumination.
In illumination engineering, always associate 'uniformity' with 'glare reduction'. If a question asks about distributing light evenly, it is almost certainly aiming to mitigate high-intensity hot spots.
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