Chapter 35317Q35.6The stealth fighter is designed so that adjacent panels are not joined at right angles, to prevent anyretroreflection of radar signals. This means that radar signals directed at the fighter will not bechanneled back toward the detector by reflection. Just as with sound, radar signals can be treated asdivergingrays, so that any ray that is by chance reflected back to the detector will be too weak inintensity to distinguish from background noise. This author is still waiting for the automotiveindustry to utilize this technology.Q35.7An echo is an example of the reflection of sound. Hearing the noise of a distant highway on a coldmorning, when you cannot hear it after the ground warms up, is an example of acoustical refraction.You can use a rubber inner tube inflated with helium as an acoustical lens to concentrate sound inthe way a lens can focus light. At your next party, see if you can experimentally find theapproximate focal point!
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This note was uploaded on 12/14/2011 for the course PHY 203 taught by Professor Staff during the Fall '11 term at Indiana State University .