Physics for Scientists and Engineers (Chaps 1-38)
4th Edition
ISBN: 9780132275590
Author: Douglas C. Giancoli
Publisher: Addison-Wesley
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Textbook Question
Chapter 34, Problem 45P
(II) The luminous efficiency of a lightbulb is the ratio of luminous flux to electric power input. (a) What is the luminous efficiency (%) of a 100-W, 1700-lm bulb? (b) How many 40-W, 60-lm/W fluorescent lamps would be needed to provide an illuminance of 250 lm/m2 on a factory floor of area 25 m × 30 m? Assume the lights are 10 m above the floor and that half their flux reaches the floor.
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Chapter 34 Solutions
Physics for Scientists and Engineers (Chaps 1-38)
Ch. 34.2 - A light beam in air with wavelength = 500 nm,...Ch. 34.4 - What are the values for the intensity I when (a) y...Ch. 34 - Prob. 1QCh. 34 - What is the evidence that light is energy?Ch. 34 - Why is light sometimes described as rays and...Ch. 34 - We can hear sounds around corners but we cannot...Ch. 34 - Can the wavelength of light be determined from...Ch. 34 - Two rays of light from the same source...Ch. 34 - Monochromatic red light is incident on a double...Ch. 34 - If Youngs double-slit experiment were submerged in...
Ch. 34 - Compare a double-slit experiment for sound waves...Ch. 34 - Suppose white light falls on the two slits of Fig....Ch. 34 - Why doesnt the light from the two headlights of a...Ch. 34 - Why are interference fringes noticeable only for a...Ch. 34 - Prob. 13QCh. 34 - Some coated lenses appear greenish yellow when...Ch. 34 - A drop of oil on a pond appears bright at its...Ch. 34 - (II) Derive the law of reflectionnamely, that the...Ch. 34 - (I) Monochromatic light falling on two slits 0.018...Ch. 34 - (I) The third-order bright fringe of 610 nm light...Ch. 34 - (II) Monochromatic light falls on two very narrow...Ch. 34 - (II) If 720-nm and 660-nm light passes through two...Ch. 34 - (II) A red laser from the physics lab is marked as...Ch. 34 - (II) Light of wavelength passes through a pair of...Ch. 34 - (II) Light of wavelength 680 nm falls on two slits...Ch. 34 - (II) A parallel beam of light from a HeNe laser,...Ch. 34 - (II) A physics professor wants to perform a...Ch. 34 - (II) Suppose a thin piece of glass is placed in...Ch. 34 - (II) In a double-slit experiment it is found that...Ch. 34 - (II) Two narrow slits separated by 1.0 mm are...Ch. 34 - (II) In a double-slit experiment, the third-order...Ch. 34 - (II) Light of wavelength 470 nm in air falls on...Ch. 34 - (II) A very thin sheet of plastic (n = 1.60)...Ch. 34 - (I) If one slit in Fig. 3412 is covered, by what...Ch. 34 - (II) Derive an expression similar to Eq. 342 which...Ch. 34 - (II) Show that the angular full width at half...Ch. 34 - (II) In a two-slit interference experiment, the...Ch. 34 - (III) Suppose that one slit of a double-slit...Ch. 34 - (III) (a) Consider three equally spaced and...Ch. 34 - (I) If a soap bubble is 120 nm thick, what...Ch. 34 - (I) How far apart are the dark fringes in Example...Ch. 34 - (II) (a) What is the smallest thickness of a soap...Ch. 34 - (II) A lens appears greenish yellow ( = 570 nm is...Ch. 34 - (II) A thin film of oil (nO = 1.50) with varying...Ch. 34 - (II) A thin oil slick (no = 1.50) finals on water...Ch. 34 - (II) A total of 31 bright and 31 dark Newtons...Ch. 34 - (II) A line metal foil separates one end of two...Ch. 34 - (II) How thick (minimum) should the air layer be...Ch. 34 - (II) A uniform thin film of alcohol (n = 1.36)...Ch. 34 - (II) Show that the radius r of the mth dark...Ch. 34 - (II) Use the result of Problem 33 to show that the...Ch. 34 - (II) When a Newtons ring apparatus (Fig. 3418) is...Ch. 34 - (II) A planoconvex lucite lens 3.4 cm in diameter...Ch. 34 - (II) Lets explore why only thin layers exhibit...Ch. 34 - (II) How far must the mirror M1 in a Michelson...Ch. 34 - (II) What is the wavelength of the light entering...Ch. 34 - (II) A micrometer is connected to the movable...Ch. 34 - (III) One of the beams of an interferometer (Fig,...Ch. 34 - (III) The yellow sodium D lines have wavelengths...Ch. 34 - Prob. 44PCh. 34 - (II) The luminous efficiency of a lightbulb is the...Ch. 34 - Light of wavelength 5.0 107 m passes through two...Ch. 34 - Television and radio waves reflecting from...Ch. 34 - A radio station operating at 88.5 MHz broadcasts...Ch. 34 - Light of wavelength 690 nm passes through two...Ch. 34 - Monochromatic light of variable wavelength is...Ch. 34 - Suppose the mirrors in a Michelson interferometer...Ch. 34 - A highly reflective mirror can be made for a...Ch. 34 - Calculate the minimum thickness needed for an...Ch. 34 - Stealth aircraft are designed to not reflect...Ch. 34 - Light or wavelength strikes a screen containing...Ch. 34 - Consider two antennas radiating 6.0-MHz radio...Ch. 34 - What is the minimum (non-zero) thickness for the...Ch. 34 - Lloyds mirror provides one way of obtaining a...Ch. 34 - Consider the antenna army of Example 345, Fig....Ch. 34 - A thin film of soap (n = 1.34) coats a piece of...Ch. 34 - Two identical sources S1 and S2, separated by...Ch. 34 - A two-slit interference set-up with slit...Ch. 34 - A radio telescope, whose two antennas are...Ch. 34 - In a compact disc (CD), digital information is...
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