Assignment 4

CHAPTER 12 SECTION 2 Worksheet 2NameBlock1. The distance from the planet Mercury to the sun is 5.79 X 10 10 meters. What time in minutes is required for the light from thesun to reach Mercury? (Answer t = 3.22 min)105.79 X 10 kilometers2. What is the difference in illumination on the books of two different physics students, one sitting directly under a lampproducing 135 candles of light? The other student is sitting .75 meters to the right of the first student and the lamp is located1.3 meters above the books. (Answer 27.91 lux)1.3 m.75 m3. It is recommended that the illumination be 540 lm/m 2 for newspaper reading. How far from the paper should a 475-candlesource be placed to provide this illumination. (Assume the paper is perpendicular to the light source)(Answer r = .94 meters)4. A lamp intensity of 45 candles is placed at 0.0-cm mark on a meter stick. A lamp of unknown intensity is placed at the 100-cm mark. If a light meters is equally illuminated at the 75-cm mark. Find the intensity of the unknown lamp.(Answer I = 5 candles)45 candles? candles75 cm 25 cm0 cm75 cm100 cm5. The illumination of the front wall of a classroom is designed such that it is 4 meters from the illumination source, and also 5times more illuminated than the back wall. The back wall is illuminated by the same source. If the intensity of the source is5550 candles, how far is the back wall from the source? (Answer r = 8.94 meters)E 1 E 25550 candles4 meters? meters6. An incandescent lamp of 40 candles is placed at the 0.0-cm mark on a meter stick and a lamp of 32 candles is placed at theopposite end. Where must the screen of a light meter be place so that both sides are equally illuminated?(Answer 52.8 cm from 40-candle source or 47.2 cm from 32-candle source)40 candles32 candles0 cmr1r2100 cm

CHAPTER 12 SECTION 2 Worksheet 27. A surface is 62 cm from a luminous source of 325 candles. At what angle can it be tilted and still have an illumination of.064 lm/m 2 ? (Answer 89.99 degrees)8. The amount of illumination thrown on a screen by two sources of light is the same when the distances from the lamps to thescreen are 7.2 meters and 4.4 meters respectively. If the intensity of the first lamp is 220 candles, what is the intensity of thesecond lamp? (Answer 82.16 candles)220 candles? candles7.2 m4.4 m9. A surface is 40 cm from a luminous source of 125 candles. At what angle can it be tilted and still have an illumination of450 lm/m 2 ? (Answer 54.83 degrees)10. What is the illumination on the page of a book 52cm directly below a source whose intensity is 108 candles?(Answer 399.41lux)11. What is the illumination on a point 50 cm below a 200 candle source? How about a point 1.2 meters to the right of the firstpoint? (Answer 800 lux, 45.52 lux)50cmpt11.2mpt 2