Textbook of Illuminating Engineering (intermediate Grade.)

air-gas amount axis bench brightness burner candle-power candles carbon cent Chapter colour comparison lamp daylight factor discharge lamp distance efficiency electric lamp energy distribution curve equal filament lamp flame flicker fluorescent fluorescent lamp flux emitted foot-candle foot-lamberts ft-L gas mantle give given glare horizontal illuminating engineering iso-candle light distribution light source lighting fitting low-pressure lumens lumens per square luminescence luminous flux luminous intensity mantle material measured method mixture mounting height object obtained perfect diffuser photocell photometer head plane polar curve pressure prisms produced proportional radiant energy radiation reflected light reflection factor reflector retina sensitive shown in Fig solid angle source of light spacing-height ratio spectral distribution spectral energy distribution specular reflection sphere standard steradians street lighting supply surface temperature test plate transmission factor tube tungsten tungsten filament usually vertical visible spectrum visual voltage wave-length window