For a progressive wave, State what wavelength means.
A laser light wave has wavelength $460\,\text{nm}$ in a vacuum. Calculate the period of the wave.
Laser light strikes a diffraction grating at normal incidence. Describe the diffraction of the light waves at the grating.
A diffraction grating is used with a range of visible-light wavelengths. For each wavelength, the angle $\theta$ of the fourth-order maximum from the zero-order central maximum is measured. The way $\sin\theta$ varies with wavelength $\lambda$ is shown in Fig. 4.1.
The gradient of the graph is $G$. Find an expression, in terms of $G$, for the distance $d$ between the centres of two neighbouring slits in the diffraction grating.
On Fig. 4.1, sketch a graph to show the results that would be obtained for the second-order maxima.