Physics (AS & A Level) · Oct / Nov 2025 · Paper 22 · Question 4

A laser emits visible light of a single frequency in a vacuum. The light is incident normally on a double slit and then forms a pattern of bright and dark fringes on a screen, as shown in Fig. 4.1. double slit screen dark fringe bright fringe fringe pattern on screen light 1.0 × 10–3 m 4.8 m 3.3 mm Fig. 4.1 (not to scale) The separation of the slits is 1.0 × 10–3 m. The distance from the slits to the screen is 4.8 m. The distance between the centres of adjacent dark fringes on the screen is 3.3 mm.

Read automatically from the paper; the printed page above is exact.