Term
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Definition
| The unit of luminous flux equal to the flux in a unit solid angle of one steradian from a uniform point source of one candlepower. |
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Term
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Definition
| The unit of luminous intesity approximately equal to the horizontal light output from an ordinary wax candle. |
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Term
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Definition
| The density of luminous flux incident on a surface in lumens per unit area. |
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Term
| Luminance (or brightness) |
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Definition
| The luminous flux per unit of projected (apparent) area & solid angle leaving a surface, either reflected or transmitted. |
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Term
Different visual tasks under different conditions require varying levels of illumination
The variables involved are... |
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Definition
| ...the nature of the task itself, the age of the person performing the task, the reflectances of the room and the demand for speed and accuracy in performing the task. |
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Term
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Definition
direct = when a light source in the field of vision causes discomfort & interference with the visual task.
reflected = when a light source is reflected from a view surface into the eye. |
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Term
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Definition
| when the reflected glare interferes with the viewing task. (may be corrected by; move the position of the task or the light source.) |
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Term
| 3 types of light sources... |
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Definition
(1) incandescent
(2) fluorescent
(3) high intensity discharge. |
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Term
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Definition
| Consists of a tungsten filament placed within a sealed bulb containing an inert gas. When electricity is passed through the lamp, the filament glows, producing light. |
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