(i) the principle of superposition of waves

(ii) techniques and procedures used for superposition experiments using sound, light and microwaves

PAG5

graphical methods to illustrate the principle of superposition

interference, coherence, path difference and phase difference

constructive interference and destructive interference in terms of path difference and phase difference

two-source interference with sound and microwaves

Young double-slit experiment using visible light

Learners should understand that this experiment gave a classical confirmation of the wave-nature of light.

(i) \(λ = \dfrac{ax}{D} \) for all waves where \(a ≪ D\)

(ii) techniques and procedures used to determine the wavelength of light using (1) a double-slit, and (2) a diffraction grating.

PAG5
\(d\sin{θ} = nλ \) and diffraction gratings will only be assessed at A level