Chapter 24 Wave Optics CHAPTER 24 Conceptual Questions C1 In a Young s double slit experiment both the wavelength and the slit separation are increased by 50 What happens to the distance between two adjacent bright fringes a It increases by 50 b It decreases by 50 c The distance stays the same d The distance increases by a 100 or more C2 In a Young s double slit experiment what happens to the angular separation between the fringes when the wavelength is increased at the same time that the slit separation is decreased a It increases b It decreases c It stays the same d The relative sizes of the changes need to be known before a definite answer can be given C3 A Young s double slit experiment is performed in air and then the apparatus is submerged in water What happens to the fringe separation and what can be used to explain the change if any a The separation stays the as it is the same experiment independent of the medium b The separation decreases because the frequency of the light decreases in the water c The separation increases because the wavelength of the light increases in the water d The separation decreases because the wavelength of the light decreases in the water C4 Diffraction grating 1 has half the lines cm that diffraction grating 2 does When used with a certain wavelength of light both gratings give first order maxima Which of the following statements is true for the same wavelength of light a Both gratings must also give second order maxima b Grating 1 must give a second order maximum c Grating 2 must give a second order maximum d It is possible that neither grating gives a second order maximum C5 Light travels from outside a building to inside through a pane of glass Which of the following is true regarding the phase change upon reflection in the case a No phase change occurs at either the inside surface or the outside surface of the glass b A 180o phase change occurs at both the inside surface and the outside surface 155 Chapter 24 Wave Optics c A 180o phase change occurs at the inside surface but not at the outside surface d A 180o phase change occurs at the outside surface but not at the inside surface 156 Chapter 24 Wave Optics 24 2 Young s Double Slit Experiment 1 Interference effects observed in the early 1800s were instrumental in supporting a concept of the existence of which property of light a polarization b particle nature c wave nature d electromagnetic character 2 If a wave from one slit of a Young s double slit set up arrives at a point on the screen one wavelength behind the wave from the other slit what is observed at that point a dark fringe b bright fringe c multi colored fringe d gray fringe neither dark nor bright 3 A Young s double slit has a slit separation of 2 50 10 5 m on which a monochromatic light beam is directed The resultant bright fringes on a screen 1 00 m from the double slit are separated by 2 30 10 2 m What is the wavelength of this beam 1 nm 10 9 m a 373 nm b 454 nm c 575 nm d 667 nm 4 Two narrow slits are 0 025 mm apart When a laser shines on them bright fringes form on a screen that is a meter away These fringes are 3 0 cm apart What is the separation between the second order bright fringe and the central fringe a 8 6 cm b 6 0 cm c 5 3 cm d 2 6 cm 5 In order to produce a sustained interference pattern by light waves from multiple sources which of the following conditions must be met a Sources are coherent b Sources are monochromatic c Both choices above are valid d None of the choices above are valid 157 Chapter 24 Wave Optics 6 In a Young s double slit interference apparatus by what factor is the distance between adjacent light and dark fringes changed when the separation between slits is doubled a 1 4 b 1 2 c 1 d 2 7 In a Young s double slit interference apparatus the distance from the slits to the screen is doubled The distance between adjacent light and dark fringes changes by a factor of a b c 1 d 2 8 In a Young s double slit interference apparatus by what factor is the distance between adjacent light and dark fringes changed when the wavelength of the source is doubled a 1 4 b 1 2 c 1 d 2 9 A Young s double slit apparatus is set up so that a screen is positioned 1 6 m from the double slits and the spacing between the two slits is 0 040 mm What is the distance between alternating bright fringes on the screen if the light source has a wavelength of 630 nm 1 nm 10 9 m a 0 016 m b 0 025 m c 0 032 m d 0 047 m 10 A Young s double slit apparatus is set up A screen is positioned 1 60 m from the double slits and the spacing between the two slits is 0 040 0 mm The distance between alternating bright fringes is 1 42 cm What is the light source wavelength 1 nm 10 9 m a 710 nm b 490 nm c 280 nm d 355 nm 158 Chapter 24 Wave Optics 11 A Young s double slit apparatus is set up where a screen is positioned 0 80 m from the double slits If the distance between alternating bright fringes is 0 95 cm and the light source has a wavelength of 580 nm what is the separation of the double slits 1 nm 10 9 m a 2 8 10 5 m b 4 9 10 5 m c 5 6 10 5 m d 6 0 10 5 m 12 A Young s double slit apparatus is set up The source wavelength is 430 nm and the doubleslit spacing is 0 040 mm At what distance from the double slits should the screen be placed if the spacing between alternating bright fringes is to be 2 4 cm 1 nm 10 9 m a 1 6 m b 2 2 m c 2 4 m d 2 9 m 13 A light source simultaneously emits light of two wavelengths 480 nm and 560 nm respectively The source is used in a double slit interference experiment where the slit spacing is a 0 040 mm and the distance between double slits and the screen is 1 2 m What is the separation between the second order bright fringes of the two wavelengths as they appear on the screen 1 nm 10 9 m a 0 16 cm b 0 32 cm c 0 48 cm d 0 64 cm 14 Waves from a radio station with a wavelength of 600 m arrive at a home receiver a distance 50 km …