2.3 General Behavior of Waves • Reflection • Refraction • Interference • Diffraction
Reflection The law of reflection: The angle of incidence = The angle of reflection.
Refraction The bending of a wave as it passes from one medium to another is called refraction.
Interference Interference refers to the combining or addition of two similar waves. Interference can be destructive, resulting in the effective disappearance of the waves, when they are out of phase. It can be constructive, resulting in the enhancement of the waves, when they are in phase.
Diffraction Diffraction is the bending of waves around obstacles or the edges of an opening in the same medium. It can be explained using Huygens’s principle. The amount of diffraction depends on the nature of waves and their wavelength. Sound waves diffract much more than light waves. Low-frequency (high-wavelength) sound waves diffract more than high-frequency (low-wavelength) light waves.
Diffraction in Speakers Small-diameter speakers, called tweeters, are used to produce high-frequency sound. The small diameter helps to promote a wider dispersion of the sound. The amount of bending is depends on the ratio: λ/w, λ is the wavelength and w is the width of the opening.