The refraction of light through a prism varies with the colour or wavelength of the light. This phenomenon, known as dispersion, occurs because different colours of light travel at different speeds in a medium other than vacuum. In a prism, shorter wavelengths (blue and violet light) slow down more than longer wavelengths (red and orange light) due to their higher frequency. This difference in speed causes each colour to bend at a slightly different angle as they pass through the prism, resulting in the separation of white light into its constituent colours. Thus, blue light bends more than red light when passing through a prism. This effect is not only responsible for the formation of rainbows but is also a fundamental principle in spectroscopy, the study of how light interacts with matter.

Sound waves and light waves behave differently around obstacles primarily due to their wavelengths. Sound waves typically have longer wavelengths, often comparable to or larger than everyday objects. This large wavelength allows sound waves to bend around obstacles, a phenomenon known as diffraction. Therefore, sound can be heard even when the source is blocked by an object. In contrast, light waves have much shorter wavelengths, much smaller than most everyday objects. This small wavelength limits the amount of diffraction that light can undergo, making it less likely for light to bend around obstacles. This is why we cannot see around corners or through small gaps in the same way we can hear sounds from around a corner or through a small opening.

Waves can indeed undergo both reflection and refraction simultaneously when they encounter a boundary between two different mediums. This dual interaction occurs because part of the wave energy is reflected back into the original medium, while the rest is transmitted into the new medium and undergoes refraction. For example, when light falls on a glass surface, some of the light is reflected off the surface, and the remaining light passes through the glass, bending as it enters due to refraction. The proportion of energy reflected and refracted depends on the properties of the mediums and the angle of incidence. This simultaneous occurrence of reflection and refraction is a common phenomenon in optics and is critical in various applications, including lenses, mirrors, and fibre optics.

The depth of water significantly influences the behaviour of water waves, particularly their speed and type. In deep water, where the depth is greater than half the wavelength of the waves, the waves are known as deep-water waves. These waves are not influenced by the ocean or sea bed and their speed depends mainly on their wavelength. Conversely, in shallow water, where the depth is less than one-twentieth of the wavelength, the waves feel the bottom of the water body. These are called shallow-water waves, and their speed is influenced by the water depth - they slow down as the depth decreases. In intermediate depths, waves are affected by both wavelength and depth. This relationship between water depth and wave behaviour is crucial in understanding phenomena like tsunamis, which travel as deep-water waves in the open ocean and transform into shallow-water waves as they approach land, increasing in height and decreasing in speed.

The principle of superposition is a fundamental concept in wave physics that describes how waves interact when they meet. According to this principle, when two or more waves overlap, the resultant wave displacement at any point is the sum of the displacements of the individual waves at that point. This interaction can lead to constructive interference, where waves in phase amplify each other, or destructive interference, where out-of-phase waves cancel each other out. This principle applies to all types of waves, including sound, light, and water waves. For example, in a ripple tank experiment, when two sets of waves intersect, patterns of constructive and destructive interference are observed, forming regions of calm water (destructive interference) and heightened waves (constructive interference). The principle of superposition is crucial in understanding phenomena like the formation of standing waves, sound interference patterns, and the behaviour of light in diffraction and interference experiments.