Physics (AS & A Level) · Feb / March 2024 · Paper 12 · Question 31

A student sets up an experiment to investigate double-slit interference. The student uses light of a single wavelength from a laser to illuminate a double slit so that a pattern of interference fringes is observed on the screen. [diagram: laser, double slit with slit separation r, distance p from laser to double slit, distance q from double slit to screen, screen with fringes observed here] The student finds that the fringes are very close together. What could the student decrease in order to increase the separation of the fringes on the screen?

1. Athe distance p from the laser to the double slit
2. Bthe distance q from the double slit to the screen
3. Cthe separation r of the slits
4. Dthe wavelength of the light from the laser

As printed in the paper