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Problems 1237 to Figure 38.16. A train of thought like this, at a soccer Section 38.5 Diffraction of X-Rays by Crystals NaCl, with atomic planes separated by 0.353 nm. A mono- 36. A wavelength of 0.129 nm characterizes K 2 x-rays from zinc. When a beam of these x-rays is incident on the If the interplanar spacing of NaCl is 0.281 nm, what is the predicted angle at which 0.140-nm x-rays are diffracted 38. The first-order diffraction maximum is observed at 12.6° for a crystal in which the interplanar spacing is 0.240 nm. 39. In water of uniform depth, a wide pier is supported on pilings in several parallel rows 2.80 m apart. Ocean waves Section 38.6 Polarization of Light Waves 40. Unpolarized light passes through two polaroid sheets. The axis of the first is vertical, and that of the second is at 30.0° E 0 parallel to the direction of the transmission axis. Through what angle should the disk be 42. Three polarizing disks whose planes are parallel are cen- 41. Problem 34 in Chapter 34 can be assigned with this 37. common vertical direction. A plane-polarized beam of E 0 parallel to the vertical reference direction is incident from the left on the first disk with intensity i " 10.0 units (arbitrary). Calculate the transmitted inten- sity I f when (a) ! 1 " 20.0°, ! 2 " 40.0°, and ! 3 " 60.0°; (b) ! 1 " 0°, ! 2 " 30.0°, and ! 3 " 60.0°. 43. The angle of incidence of a light beam onto a reflecting surface is continuously variable. The reflected ray is found 44. Review Problem. (a) A transparent plate with index of re- 2 is immersed in a medium with index n 1 . Light traveling in the surrounding medium strikes the top surface 2 separating media of dif- ferent refractive indices n 1 and n 3 . Is there one particular apex angle between the surfaces of the prism for which The critical angle for total internal reflection for sapphire 46. For a particular transparent medium surrounded by air, p " sin ! c . 47. How far above the horizon is the Moon when its image reflected in calm water is completely polarized? (n water " 1.33) Additional Problems 48. In Figure P38.42, suppose that the transmission axes of the max , the intensity of the beam emerging from the right disk is This means that the intensity of the emerging beam is 2 ! " (1 , cos 2!)/2 and sin 2 ! " (1 ' cos 2!)/2, and recall that ! " 3t.] 49. You want to rotate the plane of polarization of a polarized 50. Figure P38.50 shows a megaphone in use. Construct a the- I " 1 16 I
max (1 ' cos 43t) 45. I i I f 3 θ 2 θ 1 θ Figure P38.42 Problems 42 and 48. |