1. Topics
Young’s double slit experiment with laser light: Determine the wavelength of the laser light.
The double slit experiment with white light: Determine the coherence length of white light.

7. Interference and Coherence Length
The path length difference must be less than the coherence length of the light. Otherwise no definite phase relationship exists and the interference pattern is not visible.
No problem for laser light (coherence length of order or meters).
White light has much shorter coherence length  Interference pattern only visible for small m.

8. V I.A. Young’s Double Slit Experiment with Laser Light
Screen
Large Screen
(to keep laser light within your area)
Double Slit
Laser
Vary slit separation and observe changes.
Measure interference maxima spacing and determine the wavelength of the laser from it.

9. V I.B Young’s Double Slit Experiment with White Light
Diffuser
Double Slit
Incandescent Light
The double slit interference pattern (if there) will appear when looking against the direction of light propagation through the diffuser.
Try different slit widths.
Estimate coherence length of white light.

10. V I.B Young’s Double Slit Experiment with White Light
Diffuser
Double Slit
Photometer aperture
Incandescent Light
Use the photometer aperture to only let light through one slit.
Observe and explain.