1- Coherent monochromatic light with wavelength λ = 530 nm is incident on two slits that are separated by a distance d = 0.500 mm. The intensity of the radiation at a screen 2.50 m away from each slit is 168.0 W/cm2. Determine the position y1/3 at which the intensity of the central peak (at y = 0) drops to Imax/3. Ans:- 0.00108 m
• White light (400 nm < λ < 750 nm) shines onto a puddle of water (n = 1.33). There is a thin (109.7 nm thick) layer of oil (n = 1.47) on top of the water. What wavelengths of light would you see reflected? (Enter your answers from smallest to largest starting with the first answer blank. Enter NONE in any remaining answer blanks.) Ans:- 645 nm, none
• Some mirrors for infrared lasers are constructed with alternating layers of hafnia and silica. Suppose you want to produce constructive interference from a thin film of hafnia (n = 1.90) on BK-7 glass (n = 1.51) when infrared radiation of wavelength 1.39 µm is used. What is the smallest film thickness that would be appropriate, assuming the laser beam is oriented at right angles to the film? Ans:- 1.83e-07 m
• Sometimes thin films are used as filters to prevent certain colors from entering a lens. Consider an infrared filter, designed to prevent 847.0-nm light from entering a lens. Find the minimum film thickness for a layer of MgF2 (n = 1.38) to prevent this light from entering the lens. (Assume that nlens < 1.38.) Ans:- 153 nm
• White light shines on a sheet of a material that has a uniform thickness of 1.44 µm. When the reflected light is viewed using a spectrometer, it is noted that light with wavelengths of 499.2 nm, 561.6 nm, 641.8 nm, 748.8 nm, and 898.6 nm is not present in the reflected light. What is the index of refraction of the material? Ans:- 1.56
• A common interference setup consists of a plano-convex lens placed on a plane mirror and illuminated from above at normal incidence with monochromatic light. The pattern of circular interference fringes (fringes of equal thickness)—bright and dark circles—formed due to the air wedge defined by the two glass surfaces, is known as Newton's rings. In an experiment using a plano-convex lens with focal length f = 80.50 cm and index of refraction nl = 1.500, the radius of the third bright circle is found to be 0.8525 mm. Determine the wavelength of the monochromatic light. Ans:- 7.22e-07 m
• A single beam of coherent light (λ = 633 · 10−9 m) is incident on two glass slides, which are touching at one end and are separated by a t = 0.0275-mm thick sheet of paper on the other end, as shown in the figure below. Beam 1 reflects off the bottom surface of the top slide, and Beam 2 reflects of the top surface of the bottom slide. Assume that all the beams are perfectly vertical and that they are perpendicular to both slides, i.e., the slides are nearly parallel (the angle is exaggerated in the figure); the beams are shown at angles in the figure so that they are easier to identify. Beams 1 and 2 recombine at the location of the eye in the figure below. The slides are L = 7.20 cm long. Starting from the left end (x = 0) at what positions xbright do bright bands appear to the observer above the slides? (Enter your answer as a function of m. Assume x is measured in meters.)
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