1. (a) Sketch the diffraction pattern that is observed on a screen when light waves of wavelength 500 nm pass through a single slit of width 0.1 mm.
2. (b) Two such slits are brought together so they are separated by a distance of 0.4 mm. Sketch the interference pattern that will be observed on a screen.
3. (c) In what way has the single-slit diffraction pattern *modulated* the double-slit interference pattern?