Presentation on theme: "Diffraction from a Single Slit. Thought Question Consider a single slit diffraction pattern. At the first dark fringe above the middle bright fringe,"— Presentation transcript:
Diffraction from a Single Slit
Thought Question Consider a single slit diffraction pattern. At the first dark fringe above the middle bright fringe, what is the phase difference between the contribution to the field from the topmost and bottommost edges of the slit? A : 45 degrees B : 90 degrees C : 180 degrees D : 360 degrees E : None of the above
If we half the slit width, the central bright fringe a) Becomes wider b) Remains the same c) Becomes narrower
Light impinges on a single slit but suffers no significant diffraction. We conclude that the wavelength of the light is a. much shorter than the slit width. b. much longer than the slit width. c. on the order of the slit width.
λ = 5 a
λ = a
λ = a/2
λ = a/3
λ = a/5
λ = a/10
KNIFE FIGHTS AND MISSILES MATTHEW 6 26 Behold the fowls of the air: for they sow not, neither do they reap, nor gather into barns; yet your heavenly Father feedeth them. Are ye not much better than they? 34 Take therefore no thought for the morrow: for the morrow shall take thought for the things of itself. Sufficient unto the day is the evil thereof.
Why larger scale features in two-slit interference?
Resolving Power: Two Stars Seen Through a Slit
Imaging a Star with a Telescope
Circular aperture resolution
What can a spy satellite resolve? Low earth orbit: Too much drag below 300 km Low earth orbit: Too much drag below 300 km Delta IV max payload size ~5 m Delta IV max payload size ~5 m Very little light in x-ray, deep uv bands Very little light in x-ray, deep uv bands Strong atmospheric absorption below 300 nm. Fairly good transmission in visible band. Strong atmospheric absorption below 300 nm. Fairly good transmission in visible band.
Cat’s eyes have pupils that can be modeled as vertical slits. At night, would cats be more successful in resolving A. Two headlights on a distant car B. Vertically separated lights on the mast of a distant boat C. If the two sets of lights are the same distance away, the ability to resolve them would be the same.
Diffraction Gratings (Resolving power means something different here)