Physics (AS & A Level) · Feb / March 2020 · Paper 12 · Question 28

The table shows four possible combinations of values for the laser wavelength, slit separation and slit-screen distance in a two-slit interference experiment to show the interference of visible light on a white screen. Which combination will result in visible fringes being observed?

1. Alaser wavelength 200 nm, slit separation 0.10 mm, slit-screen distance 5.0 m
2. Blaser wavelength 200 nm, slit separation 100 mm, slit-screen distance 1.0 m
3. Claser wavelength 600 nm, slit separation 0.10 mm, slit-screen distance 5.0 m
4. Dlaser wavelength 600 nm, slit separation 100 mm, slit-screen distance 1.0 m

As printed in the paper