Physics 5B UCSC
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| Consider a beam of coherent monochromatic light, like a pencil shaped beam of a laser. At a certain time and position, the beam shape is a perfect circle of diameter D. However, it is moving in free space. Will this beam show a diffraction pattern at a screen some distance away later on? | Consider a beam of coherent monochromatic light, like a pencil shaped beam from a laser. At a certain time and position, the beam shape is a perfect circle of diameter D. However, it is moving in free space. Will this beam show a diffraction pattern at a screen some distance away later on? |
Lecture 17: Chapter 35 (Diffraction)
Thin film interference
Consider two identical microscopic slides in air illuminated with light from a laser. The bottom slide is rotated upward so that the wedge angle gets a bit smaller. What happens to the interference fringes?
- spaced farther apart
- spaced closer together
- no change
Thin film interference
Two identical microscope slides in air illuminated with light from a laser are creating an interference pattern. The space between the slides is now filled with water (n = 1.33). What happens to the interference fringes?
- spaced farther apart
- spaced closer together
- no change
Diffraction
The diffraction pattern below arises from a single slit. If we would like to sharpen the pattern, i.e., make the central bright spot narrower, what should we do to the slit width?
- narrow the slit
- widen the slit
- enlarge the screen
- close off the slit
Diffraction
Imagine holding a circular disk in a beam of monochromatic light. Diffraction occurs at the edge of the disk. The center of the shadow is
- darker than the rest of the shadow
- a bright spot
- bright or dark, depending on the wavelength
- bright or dark, depending on the distance to the screen
Diffraction?
Consider a beam of coherent monochromatic light, like a pencil shaped beam from a laser. At a certain time and position, the beam shape is a perfect circle of diameter D. However, it is moving in free space. Will this beam show a diffraction pattern at a screen some distance away later on?
- Yes, sure.
- No way.