recall and use Malus’s law (I = I0 cos² θ) to calculate the intensity of a plane-polarised electromagnetic wave after transmission through a polarising filter or a series of polarising filters (calculation of the effect of a polarising filter on the intensity of an unpolarised wave is not required)

describe the use of a diffraction grating to determine the wavelength of light (the structure and use of the spectrometer are not included)

show an understanding of experiments that demonstrate diffraction including the qualitative effect of the gap width relative to the wavelength of the wave; for example diffraction of water waves in a ripple tank