II. SINGLE-SLIT INTERFERENCE You have learned that when light interacts with obj
ID: 1498088 • Letter: I
Question
II. SINGLE-SLIT INTERFERENCE You have learned that when light interacts with objects whose size is comparable (within a factor of 1000 or so) to the wavelength of the light, the wavelike behavior of light becomes significant. An example of this is double slit interference. You decide to investigate the behavior of light when it passes through a single slit.
Design an experiment to investigate quantitatively how the width of the slit affects the pattern that you see on the screen.
Available equipment: Several single slits (the plastic wheel labeled “single slit set”), laser, meter stick, viewing screen, paper, masking tape.
a) What main steps do you have to follow to accomplish the task? (Hint: Which of the 3 kinds of experiment is this?)
b) Devise, describe and perform the experiment according to the steps you described.
c) Clearly describe the relationship you discovered, both with words and as a mathematical relation.
d) Use the wave model of light to explain why a pattern appears at all. How come you don’t just see a single bright spot? See if you can apply the ideas of interference that explain the double-slit interference pattern.
Explanation / Answer
a)
Here, given single slit, we can perform single slit experiment and obtain the fringe patter.
b)
With a known monochromatic wavelength incident on single slit, the diffraction pattern can be obtained and then by calculating the values, by
y = m*wavelength*D/a , where D is length between screen and Grating
a is slit width
c)
Use different slit widths, vary 'a' and accordingly measure the observables 'y' and study how the width of the slit affects the pattern that you see on the screen.
d) because of diffraction, we see a intensity distribution on the screen.