![sound diffraction equation sound diffraction equation](https://i.stack.imgur.com/63I9A.png)
Because S-waves do not pass through the liquid core, two shadow regions are produced ( Figure). The time between the P- and S-waves is routinely used to determine the distance to their source, the epicenter of the earthquake. the wavelength of the light (m) d the slit separation (m) This means, for n 1: Similarly, for n 2, where the path. Using trigonometry, an expression for the first order maxima can be written: Where: the angle between the normal and the maxima. The P-wave gets progressively farther ahead of the S-wave as they travel through Earth’s crust. Using this diagram and trigonometry, the diffraction grating equation can be derived. P-waves have speeds of 4 to 7 km/s, and S-waves range in speed from 2 to 5 km/s, both being faster in more rigid material. The fact that you can hear sounds around corners and around barriers involves both diffraction and reflection. Important parts of our experience with sound involve diffraction. Both types of earthquake waves travel slower in less rigid material, such as sediments. Diffraction: the bending of waves around small obstacles and the spreading out of waves beyond small openings. For that reason, the speed of longitudinal or pressure waves (P-waves) in earthquakes in granite is significantly higher than the speed of transverse or shear waves (S-waves). The bulk modulus of granite is greater than its shear modulus. Earthquakes produce both longitudinal and transverse waves, and these travel at different speeds. Seismic waves, which are essentially sound waves in Earth’s crust produced by earthquakes, are an interesting example of how the speed of sound depends on the rigidity of the medium. The second shell is farther away, so the light arrives at your eyes noticeably sooner than the sound wave arrives at your ears.Īlthough sound waves in a fluid are longitudinal, sound waves in a solid travel both as longitudinal waves and transverse waves. The first shell is probably very close by, so the speed difference is not noticeable. Sound and light both travel at definite speeds, and the speed of sound is slower than the speed of light. V=\sqrt Differentiating with respect to the density, the equation becomes