Homework

1) Consider the spacing and peak widths of the light patterns produced by diffraction and interference of light.

a) The spacing of the minima in the patterns produced by a green laser will be: greater than, less than or equal to that of a red laser. Justify your answer.

b) The width of the peaks, W and/or Wo, of the pattern for the green laser will be: greater than, less than or equal to that of a red laser. Justify your answer.

2) Light from a HeNe laser (λ = 632.8 nm) strikes a pair of slits at normal incidence, forming a double slit pattern on a screen 1.4 m from the slits, as shown in the figure below. What is the slit spacing?

3) An experiment is performed by passing light through one or two slits and the light pattern to the right is produced. Determine the best answer and explain how you can tell:

a) the pattern produced was a result of a double slit interference experiment

b) the pattern produced was a result of a single slit diffraction experiment

c) More information is needed, i.e. the wavelength of the source, the distance it is from the slit(s) and how far the slit is to the viewing screen, before it can be determined which type of experiment produced the pattern

4) Now, you observe the following light pattern. Select all the possible changes in experimental conditions that might have caused the differences in the original pattern (that shown in problem 3) to that which you observe now.

a) the wavelength of the light source was increased

b) the wavelength of the light source was decreased

c) the slit width/slit separation was increased

d) the slit width/slit separation was decreased

e) the experiment was changed from a double slit to single slit

f) the experiment was changed from a single slit to a double slit