Double Slit Interference
BlackBoard Notes

• Note to Jeff: Write Fourth Board Section first!

======================= Photo - Click for a Larger Version =============================

======================= First Board Section =============================

• Calculate wavelength of laser, λ from interference pattern: *A lab practical skill!
• Calculate uncertainty in λ due to uncertainity in other parameters (Not for practical!)
• Use a flashlight? Turn off and tip over when finished!

  

======================= Second Board Section =============================

• Sketch:

d ≡ distance between centers of slits

Plot xn vs. n, apply a linear fit.

======================= Third Board Section =============================

• Measuring d: (Note to Jeff: slits are horizontal if using Delineascope, vertical if using overhead projector for Cornell slide projection!)

	Image of Slits Projected on the Wall
	Set up a proportion:

======================= Fourth Board Section - Write this section FIRST: Tight on space!! =============================

• Note to Jeff: Write two columns for equations; split between b and c

• Uncertainty in wavelength {Δλ}:
  • Depends on uncertainty in slope and uncertainty in d

1. Uncertainty in wavelength due to uncertainty in slope (use Δm from your graph):



2. Uncertainty in slit spacing (where Δd_wall comes from your measurements of d_wall):

   

3. Uncertainty in wavelength due to uncertainty in slit spacing:



4. Calculate uncertainty in wavelength:

   

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Revised: 21 Mar 2022

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