An elementary book on electricity and magnetism and their applications (1919)
Jackson, Dugald C. (Dugald Caleb), 1865-1951, Jackson, John Price, b. 1868, Black, Newton Henry, b. 1874 · New York, The Macmillian Co · leaf 525
Fig. 332.—Vertical distribution for a lamp when fitted with a shade andwithout a shade. Note. — A one-candle-power lamp placed in the center of a sphereof one foot radius shines on 12.56 (47r) square feet of surface. Thelight which shines on one square foot at a distance of one foot from alamp of…
Electricity · Magnetism
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