🤓 Based on our data, we think this question is relevant for Professor Tsai's class at UCSD.
Both the double-slit interference pattern and single-slit diffraction patterns are observable. A diffraction pattern is formed in a double-slit when the slits are wide enough.
Double-slit interference pattern (maxima condition),
where, a = slit width and d = slit's separation distance.
Draw the pattern you observed on the screen for the red laser. Which aspect of your drawing is due to double-slit interference, and which is due to single-slit? How can you tell? Indicate these on your drawing.
What happens to the pattern when you:
a. Increase the wavelength (What happen for double-slit pattern and single-slit pattern ?)
b. Slits are moved closer (What happen for double-slit pattern ?)
c. Each slit is widened (What happen for single-slit pattern?)