Ex) Calculate the distance between two
slits in a Double Slit Experiment if the
wavelength of the light used is is 5 x 10-7 m and the distance between the
central maximum and the first order bright line is 2 x 10-2 m. The distance from the slits to
the screen is 4 meters.
λ/d = x/L
(5 x 10-7 m)/d = (2 x 10-2 m)/4 m
Answer d = 1 x 10-4 m
Question: If they give you d, L and x and asked you to find the COLOR of the
light used, What would you do? Where would you go to find the color?
Answer:
1. Solve for
λ use Young's Equation
2. Use 3 x 108 m/s = fλ
to find the colors frequency
3. Look up the color on page 2 Ref.
Check Your Understanding
5 quick questions — pick an answer to see if you’re right.
1. Which behavior is diffraction?
2. Young's double-slit experiment produced a pattern of bright and dark lines. This supports the wave theory because it shows
3. At a point on the screen, light from the two slits has a path difference of 1½ λ. What appears there?
4. Light of λ = 5 × 10⁻⁷ m passes through slits 1 × 10⁻⁴ m apart onto a screen 2 m away. How far is the first bright line from the center?
5. What type of light source gives the clearest double-slit pattern?
