Usually involves feeling of fear or insecurity. The loss of confidence in things that have always been stable or dependable in the past â this includes things such as a relationship, your personality structure, health, etc; so the breakdown of opinions, attitudes or relationships which seemed so dependable and you have taken for granted.
Crests and troughs. Waves have moving crests (or peaks) and troughs. A crest is the highest point the medium rises to and a trough is the lowest point the medium sinks to. Crests and troughs on a transverse wave are shown in Figure 1. A crest is a point on the wave where the displacement of the medium is at a maximum.
Wavefronts and Huygens Principle. A wavefront is a surface over which an optical wave has a constant phase. For example, a wavefront could be the surface over which the wave has a maximum (the crest of a water wave, for example) or a minimum (the trough of the same wave) value.The shape of a wavefront is usually determined by the geometry of the source.he same construction is used for a wavefront of any other shape. When a wave travels in a single medium at a constant speed, the Huygen s construction preserves the general form of the wavefront. That is, spheres propagate and become larger spheres, cylinders become larger cylinders, etc.