Conceptual Questions
4.1 Single-Slit Diffraction
As the width of the slit producing a single-slit diffraction pattern is reduced, how will the diffraction pattern produced change?
Compare interference and diffraction.
If you and a friend are on opposite sides of a hill, you can communicate with walkie-talkies but not with flashlights. Explain.
What happens to the diffraction pattern of a single slit when the entire optical apparatus is immersed in water?
In our study of diffraction by a single slit, we assume that the length of the slit is much larger than the width. What happens to the diffraction pattern if these two dimensions were comparable?
A rectangular slit is twice as wide as it is high. Is the central diffraction peak wider in the vertical direction or in the horizontal direction?
4.2 Intensity in Single-Slit Diffraction
In Equation 4.4, the parameter looks like an angle but is not an angle that you can measure with a protractor in the physical world. Explain what represents.
4.3 Double-Slit Diffraction
Shown below is the central part of the interference pattern for a pure wavelength of red light projected onto a double slit. The pattern is actually a combination of single- and double-slit interference. Note that the bright spots are evenly spaced. Is this a double- or single-slit characteristic? Note that some of the bright spots are dim on either side of the center. Is this a single- or double-slit characteristic? Which is smaller, the slit width or the separation between slits? Explain your responses.
4.5 Circular Apertures and Resolution
The resolving power of refracting telescope increases with the size of its objective lens. What other advantage is gained with a larger lens?
The distance between atoms in a molecule is about . Can visible light be used to “see” molecules?
A beam of light always spreads out. Why can a beam not be created with parallel rays to prevent spreading? Why can lenses, mirrors, or apertures not be used to correct the spreading?
4.7 Holography
How can you tell that a hologram is a true three-dimensional image and that those in three-dimensional movies are not?
If a hologram is recorded using monochromatic light at one wavelength but its image is viewed at another wavelength, say shorter, what will you see? What if it is viewed using light of exactly half the original wavelength?
What image will one see if a hologram is recorded using monochromatic light but its image is viewed in white light? Explain.