 | Daniel Evan Jones - 1891 - 358 páginas
...the screen and adjusting these to equality. (2) The illuminating powers of the two sources of light are directly proportional to the squares of their distances from the screen. If the distances had been I ft. and 3 ft. (instead of I ft and 2 ft.), the illuminating powers would... | |
 | John Hornby - 1900 - 336 páginas
...screen, and adjusting these to equality ; also that the illuminating powers of the two sources of light are directly proportional to the squares of their distances from the screen. If the distances had been 1 foot and 3 feet (instead of 1 foot and 2 feet), the illuminating powers... | |
 | Robert Wallace Stewart - 1909 - 236 páginas
...therefore, _A_ — ._k. or i (D,)' - (D2)*' I2 That is, the illuminating powers of the sources of light are directly proportional to the squares of their distances from the screen, when these distances are so adjusted that each source gives separately the same intensity of illumination... | |
 | Frederick Condit Reeve - 1912 - 208 páginas
...intensity of illumination at their respective distances from the screen. Hence their candle powers are directly proportional to the squares of their distances from the screen. In some forms of Bunsen photometer mirrors are provided for viewing both sides of the translucent spot... | |
 | Newton Henry Black - 1913 - 142 páginas
...same brightness. Since it s T\ y ir 1 1 1 1 1 II P" 1 1 1 |7 ^\ 1 II IEyes\ X A em ft. 1 1 1 1 1 1 1 is difficult to set this sight box or screen precisely,...their distances from the screen. That is, „ . 2 ~s = W In this way, knowing S and measuring A and .B, we can compute X. Find the candle power of an ordinary... | |
 | Newton Henry Black, Harvey Nathaniel Davis - 1913 - 530 páginas
...equally illuminated on both sides, and the distances A and B are measured. LIGHT: LAMPS AND REFLECTORS has the greater candle power. Furthermore, since the...to the squares of their distances from the screen. For example, let 16 = candle power of lamp S, t~ ^ and X = candle power of lamp X. ,< Let 80 cm. =... | |
 | Newton Henry Black - 1913 - 540 páginas
...distances A and B are measured. , FIG. 381.— Bunsen light hox with screen. LIGHT: LAMPS AND REFLECTORS has the greater candle power. Furthermore, since the...to the squares of their distances from the screen. For example, let 16 = candle power of lamp S, and X = candle power of lamp X. Let 80 cm. = distance... | |
 | Newton Henry Black, Harvey Nathaniel Davis - 1915 - 532 páginas
...distances A and B are measured. FIG. 381.— Bunsen light box with screen. 410 LIGHT: LAMPS AND REFLECTORS has the greater candle power. Furthermore, since the...to the squares of their distances from the screen. For example, let 16 = candle power of lamp S, and X = candle power of lamp X. Let 80 cm. = distance... | |
 | Newton Henry Black, Harvey Nathaniel Davis - 1915 - 534 páginas
...distances A and B are measured. FiG. 381 .— Bunsen light box with screen. LIGHT: LAMPS AND REFLECTORS has the greater candle power. Furthermore, since the...to the squares of their distances from the screen. For example, let 16 = candle power of lamp S, and X = candle power of lamp X. Let 80 cm. = distance... | |
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REFLECTORS has the greater candle power. Furthermore, since the intensity of illumination decreases as the square of the distance, the candle powers of the two lamps are directly proportional to the squares of their distances from the screen. For example,... 
