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 224
les concentric with themrepresent the areas illuminated by the respective lamps. It will be readily understood that in oider to secure approx-imately uniform illumination with a number of lamps theillumination due to each lamp must decrease with departurefrom beneath the source. Polar candle-power… … 90° ^ 2aaO pC4 f^Sfer+-~Ii 80° h—V^-5^? V^Kv T \>P^^T\ \\\y\.y^ //ToC, >\^^^s(jf\- s —x/3<^ ^^^^^ ^ X yEB 0 12 3 4 Feet Figs. 113 and 114.—Polar curves for uniform illumination. 20 %. 30 S 40 50 A and B and a study will be made of the distribution of lightin a vertical j^lane through the…
Light · Photometry · Electric lighting
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