For a progressive water wave, state the meaning of displacement.
For a progressive water wave, state the meaning of amplitude.
Two coherent waves X and Y arrive at the same point and superpose. The phase difference between the waves at the point is $180^\circ$. Wave X has an amplitude of $1.2\,\text{cm}$ and intensity $I$. Wave Y has an amplitude of $3.6\,\text{cm}$. Calculate, in terms of $I$, the resultant intensity at the point where they meet.
Monochromatic light falls on a diffraction grating. Describe the diffraction of the light waves as they pass through the grating.
A parallel beam of light contains two wavelengths $540\,\text{nm}$ and $630\,\text{nm}$. The light is incident normally on a diffraction grating. Third-order diffraction maxima are obtained for both wavelengths. No higher orders are obtained for either wavelength. Determine the smallest possible line spacing $d$ of the diffraction grating.
In (c)(ii), the beam of light is replaced by a beam of blue light incident on the same diffraction grating. State and explain whether a third-order diffraction maximum is produced for this blue light.