Very confused! the way in which a wave behaves when it reaches the end of the medium through which it was traveling is often called boundary behavior. the boundary behavior of light waves is best summarized by the following statements: the wavelength is always longest in the least optically dense medium. the frequency of a wave is not altered by crossing a boundary. the amplitude of an original pulse is always greater than the amplitude of a reflected pulse. given the above information, and given that solids generally have greater optical densities than liquids, and that liquids generally have greater optical densities than gases, which of the following statements is true? the number of wavelengths per unit time will change as a light wave moves from a solid into a liquid. the wavelength of a light wave will increase as it moves from a gas into a liquid. the wavelength of a light wave will increase as it moves from a liquid into a solid. the number of wavelengths per unit time will not change as a light wave moves from a solid into a liquid.