Unit 6 Practice Exercises 6.] Properties of Light Waves 1. Suggest why only transverse waves can be polarized. 2. If the Sun suddenly turned off, we would not know it until its light stopped coming. How long would that be, given that the Sun is 1.50 X 1011 m away? 3. Two disks of Polaroid are aligned so that they polarize light in the same plane. Calculate the angle through which one sheet needs to be turned in order to reduce the amplitude of the observed E-fleld to U4 of its original value. 4. Polarized light is incident on a polarizer whose transmission axis makes an angle of 30 with the direction of the electric eld of the incident light. Calculate the fraction of the incident light intensity that is transmitted through the polarizer. 6.2 Refraction 1. Blue light of wavelength 4.6x10'T m in air enters glass with a refractive index of 1.583, with an angle of incidence of 38. Calculate: a) the angle of refraction b) the speed oflight in the glass e) the wavelength of light in the glass. 2. Suppose you have an unknown clear substance immersed in water, and you wish to identify it by nding its index of refraction. You arrange to have a beam of light enter it at an angle of 450, and you observe the angle of refraction to be 403. What is the index of refraction of the substance? 3. What is the critical angle for light going from water to air? 4. A light wave traveling in air strikes a piece of glass. The frequency ofthe incident wave is 5.1xI0i4 Hz. The angle of incidence is 28 and the angle of refraction is 22". 21) Find the speed of light in the glass. b) Find the index of refraction of the glass. c) Find the wavelength of the incident light wave. d) Find the frequency and wavelength of the refracted light wave, 6) What is the critical angle of the light once it is inside the glass? 5. Light of frequency 4.0x 1014 Hz strikes a glassfair boundary at an angle of incidence 61 = 25. The ray is partially reected and partially refracted at the boundary, as shown. The index of refraction of this glass is 1.6. a) Determine 93. b) Determine 92. c) Determine the speed of light in the glass. (1) Determine the wavelength of the light in the glass. e) What is the largest value of 91 that will result in a refracted ray? 6.1 and 6.2 Problems.pdf - Goc X + a drive.google.com/file/d/1GGBmvj48SeMKjajJNBagQqkZiCC6loto/view Update PDF 6.1 and 6.2 Problems.pdf Open with 4 N 6. A man shines a flashlight from a boat into the water, illuminating a rock. Using the information in the picture to the right, what is the angle of incidence 01? 3.00 m | 02 1 2.50 m- 7. A light ray enters a block of plastic and travels along the path shown above. a) By considering the behavior of the ray at point P, determine the speed Air of light in the plastic 5301 37. Plastic b) Determine what will happen to the light ray when it reaches point Q, using the diagram above to illustrate your conclusion. in Vacuum of Glass Red Light 700 nm Light Blue Light 480 nm 8. The glass prism shown above has an index of refraction that depends on the wavelength of the light that enters it. The index of refraction is 1.50 for red light of wavelength 700 nm in a vacuum and 1.60 for blue light of wavelength 480 nm in vacuum. A beam of white light is incident from the left, perpendicular to the first surface, as shown in the figure, and is dispersed by the prism into its spectral components. a) Determine the speed of the blue light in the glass. b) Determine the wavelength of the red light in the glass. c) Determine the frequency of the red light in the glass. d) On the figure above, sketch the approximate paths of both the red and the blue rays as they pass through the glass and back out into the vacuum. Ignore any reflected light. It is not necessary to calculate any angles, but do clearly show the change in direction of the rays, if any, at each surface and be sure to distinguish carefully any differences between the paths of the red and the blue beams. e) The figure below represents a wedge-shaped hollow space in a large piece of the type of glass described above. On this figure, sketch the approximate path of the red and the blue rays as they pass through the hollow prism and back into the glass. Again, ignore any reflected light, clearly show changes in direction, if any, where refraction occurs, and carefully distinguish any differences in the two paths Vacuum Glas Page 2 / 2 - +