Q. Carbon arc lamps need frequent adjustment and replacement of carbon rod.
Q. Lumen method takes into account the inter-reflections of light inside a room.
Q. Luminaires are generally categorized as industrial, commercial or residential.
Q. Lenses with prismatic patterns refract light sources to disperse the rays or to direct them most effectively.
Q. High-pressure sodium vapour Lamps use metallic sodium sealed in translucent aluminium oxide tubes.
Q. A standard candle is also known as meter candle.
Q. Incandescent-lamp filaments are generally constructed of copper.
Q. Candelabra refers to the base of an incandescent lamp.
Q. The luminous efficacy is expressed in lumen output per radiated watt.
Q. Lumen is the unit of luminous flux.
Q. Illuminance is the density of luminous flux on a surface.
Q. A source of one candela emits a total of one lumen.
Q. Glare is the condition of comfort produced by an object of luminance.
Q. Incandescent lamps should always be used without luminaries.
Q. The diameter of tungsten filament for GLS lamps is in terms of microns.
Q. Halogen lamps are preferred for indoor illumination.
Q. A starter in a fluorescent tube is used for preheating the electrodes.
Q. Starter use for a fluorescent tube is a generally glowing type.
Q. After about 4000 hours of use, the light output of a fluorescent tube is reduced by 15 to 20%.
Q. Sodium vapour lamp is also known as a cold-cathode low-pressure lamp.
Q. With the use of a fluorescent tube, walls blacken little and dark rings appear near the ends due to the deposition of active material from the electrodes.
Q. Fluorescent tubes operating on dc are generally free from stroboscopic effect.
Q. A ‘leak transformer’, provided on sodium lamps acts as a step-down transformer initially.
Q. The average life of sodium lamps is estimated at 6000 hrs.
Q. Mercury iodide lamps are used for flood lighting.
