Origin of wave front
Examples from the Web for wave front
Hence the wave-front is tilted towards the base of the prism, and this tilting is repeated when the wave-front leaves the prism.
The contrary is the case when the wave-front passes into a medium where its velocity is greater.
The middle of the wave-front now travels faster than the flanks, and the curvature is increased.
With a dense prism, the wave-front of the shorter waves is more tilted towards the base than the wave-front of the longer waves.
Hence the wave-front is flattened, the curvature of the refracted wave being less than that of the original wave of diffusion.