PHYS 1112
Chapter 24 Problems

Chapter Objectives

  1. Describe the interference pattern that results from monochromatic light passing through a) a single slit, b) a double slit, and c) multiple slits.
  2. Calculate the appearance of bright and dark fringes due to monochromatic light passing through a single slit.
  3. Calculate the appearance of bright and dark fringes due to monochromatic light passing through a double slit.
  4. Calculate the appearance of bright fringes due to monochromatic light passing through a diffraction grating.
  5. Describe the interference of light that reflects from thin films.  Calculate the wavelengths that will have complete constructive and destructive interference due to reflection from thin films.
  6. Describe Brewster's law.  Calculate the amount of light that passes through a polarizing plate given the initial polarization vector of the light and the orientation of the plate's polarization vector.

Conceptual Questions

  1. When oil is spread thinly across the surface of water, it appears as if a rainbow were laid out over and over across the surface of the water when it is viewed from an acut angle. Why?
  2. Camera lenses that have non-reflective coatings appear to be colorful (usually dark blue or purple). Why?
  3. When view at an angle to the light, CD's appear to be colorful on their reflective side. Why?
  4. Can you polarize sound waves?
  5. Why can you hear someone around an open doorway even when you cannot see them?

Selected Problems

  1. A thin layer of liquid methylene iodide (n = 1.756) is sandwiched between two flat parallel plates of glass. What must be the thickness of the liquid layer if normally incident light with l = 600 nm in air is to be strongly reflected?
  2. Two rectangular optically flat plates (n = 1.52) are in contact along one end and are separated along the other end by a sheet of paper that is 4.00 x 10-3 cm thick. The top plate is illuminated by monochromatic light of wavelength 546.1 nm. Calculate the number of dark parallel bands crossing the top plate (including the dark band at zero thickness along the edge of contact between the two plates).
  3. A light beam is incedent on heavy flint glass (n = 1.65) at polarizing angle. Calculate the angle of refraction for the transmitted ray.
  4. Two narrow slits separated by 1 mm are illuminated by light of wavelength 600 nm, and the interference pattern is viewed on a screen 2 m away. Calculate the number of bright fringes per centimeter on the screen.

Solutions

If you find an error in these, or just have a comment, send an e-mail message to jpratte@kennesaw.edu