# Question: observational experiment singleslit diffraction you have learned that when light...

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Observational Experiment: Single-slit diffraction

You have learned that when light interacts with objects whose size is at most a few powers of ten larger than the wavelength of the light (within a factor of 1000 is a good rule-of-thumb) the wavelike behavior of light becomes easily noticeable. An example of this is double-slit interference (the first experiment in today’s lab). You decide to investigate the behavior of light when it passes through a single slit. This is the first time you’ll be designing and performing an observational experiment. You have not learned about single-slit interference in lecture, you don’t know what’s going to happen, and you don’t have an equation that relates the relevant quantities. You don’t even know what the relevant quantities are! The goal of this experiment is to start investigating the phenomenon of single-slit interference.

Available equipment: Google Sheets for data analysis, Red laser, Green laser, Several thin single-slits mounted on a plastic wheel labelled “Single Slits”, with width a specified, Meter stick, Viewing screen, Paper

Include the following in your writeup:

a) First, use the available equipment to make laser light pass through a single slit then onto the viewing screen. Describe what you see in words. Include a picture.

b) What features of the pattern can you measure with the available equipment? Think about what factors those features might depend on.

c) Devise, describe (words + labeled diagrams), and perform an experiment to investigate single-slit interference. Specifically you need to develop a mathematical relationship between measurable physical quantities. Refer to rubric elements F1, B3 for guidance.

d) Clearly describe the relationship you discovered, both with words and as a mathematical equation. There’s no right or wrong mathematical equation as long as it fits your collected data. When there are several good choices for the best-fit equation to your data, choose the simplest one. Refer to rubric element B8