![]() However, since atoms are on the order of 0.1 nm in size, X-rays can be used to detect the location, shape, and size of atoms and molecules. Thus, typical X-ray photons act like rays when they encounter macroscopic objects, like teeth, and produce sharp shadows. 4.7: X-Ray Diffraction Since X-ray photons are very energetic, they have relatively short wavelengths.The acuity of our vision is limited because light passes through the pupil, which is the circular aperture of the eye. This can be used as a spectroscopic tool-a diffraction grating disperses light according to wavelength, for example, and is used to produce spectra-but diffraction also limits the detail we can obtain in images.Diffraction limits the resolution in many situations. 4.6: Circular Apertures and Resolution Light diffracts as it moves through space, bending around obstacles, interfering constructively and destructively.Constructive interference occurs when \(d \space sin \space \theta = m \lambda\) form = 0, ± 1, ☒., where d is the distance between the slits, θ is the angle relative to the incident direction, and m is the order of the interference. 4.5: Diffraction Gratings A diffraction grating consists of a large number of evenly spaced parallel slits that produce an interference pattern similar to but sharper than that of a double slit. ![]() Missing orders occur when an interference maximum and a diffraction minimum are located together. Relative intensities of interference fringes within a diffraction pattern can be determined. 4.4: Double-Slit Diffraction With real slits with finite widths, the effects of interference and diffraction operate simultaneously to form a complicated intensity pattern.Reverb and standing waves can be controlled by adding absorption materials to a room.\), D is the slit width, λλ is the wavelength, and θθ is the angle from the central peak. Figure 3 - Example of a sound wave diffracting around a gap in a surface AbsorptionĪbsorption is the loss of sound through an absorbent material. High-frequency waves have high directivity and can easily be blocked, whereas low frequencies have low directivity and spread far and wide. ![]() For spreading to happen, the wave must be larger than the object. Figure 2 - Example of an incoming sound wave refracting as it hits the water Diffractionĭiffraction is the bending of waves around small objects and the spreading out of a wave through small openings.Īll waves tend to spread out at the edge when they pass through a gap or past an object. Since temperature decreases with height, the speed of sound also decreases with height. With sound waves, it is more common for the sound to refract when it encounters a change in air temperature. Refraction is the process where a waveform changes direction as it passes from one medium to another - the speed of the wave changes as this happens. Figure 1 - Example of an incoming sound wave, reflecting back off a large surface Refraction Reflection is responsible for producing echo, reverb , and standing waves. The reflected sound will have a different frequency characteristic than the direct sound if all frequencies are not reflected equally. ![]() Higher frequency sound can be reflected by both small and large objects. Low-frequency sound has a long wavelength and so can only be reflected by large objects. For sound to be reflected, the object must be physically as large, or larger than the wave. Reflection is the process whereby part or the entire wave is returned when it encounters a boundary. Sound waves react in different ways when they interact with an obstacle reflection, refraction, absorption, and diffusion.
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