Light, photometry and illumination : a thoroughly rev. ed. of ''Electrical illuminating engineering'' (1912)
Barrows, William Edward, 1878-1960 · New York ; London : McGraw-Hill Book Co. · leaf 225
vertical,then the intensity of illumination at d^ duo to the source, may beexpressed as follows: since „- = , ,, and d — h tan a, (109) -p- {d—h tan a) = p—» (110) therefore, the equation for this curve is E„J^/d:-AtanaY cos^a \ d J This is the simplest form of curve for uniform illumination witha… … ;0 a> 40 O 0 12 3 4 5 Feet Figs. 115 and 116.—Polar curves for uniform illumination. placed at the corners of a square the illumination along the sidesof the square will be uniform, but not so at the intersection ofthe diagonals of the square. The illumination of this point isfour times the…
Light · Photometry · Electric lighting
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