LAB #11: Diffraction
Theory:
• What is diffraction?
• Define Hygen’s Principle.
• What happens when light passes through the narrow slit? What kind of diffraction
pattern you’ll get?
• What is the path difference between two rays and how it can be determined?
• When one can obtain diffraction minima?
Experiment: For both parts of the experiment use slit B on the single-slit diaphram.
aknown=0.24mm
1. Low sensitivity (Gain=10)
a. Sweep the light sensor across the diffraction pattern to get Intensity vs.
position
b. Record position of the 1st order minimum (m=±1)
Y − Y+1
c. Distance between minima is 2Y; Y = −1
2
d. Calculate a from equation 11.9.
2. High Sensitivity (Gain=100)
a. Record positions of m=-3 to m=+3 minima
b. Plot m vs. Y in JagFit
c. Calculate a from the slope
•
Compare both a calculation with the known value aknown=0.24mm