Physics (AS & A Level) · May / June 2026 · Paper 11 · Question 30

Green light of wavelength 550 nm passes through a double slit. This produces an interference pattern with a fringe spacing of 5.0 cm on a screen. Which changes to the experimental arrangement result in a fringe spacing of 2.5 cm?

1. Aslit separation doubled, distance between slits and screen unchanged
2. Bslit separation unchanged, distance between slits and screen doubled
3. Cslit separation halved, distance between slits and screen doubled
4. Dslit separation doubled, distance between slits and screen halved

As printed in the paper