Question
Some radar systems detect the size and shape of objects such as aircraft and geological terrain. Approximately what is the smallest observable detail utilizing 500-MHz radar?
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Solution video
OpenStax College Physics, Chapter 24, Problem 14 (Problems & Exercises)
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This is College Physics Answers with Shaun Dychko. We want to know what is the size of the smallest observable detail when using radar that has a frequency of 500 megahertz, which is 500 times 10 to the 6 hertz? The smallest observable detail is approximately the size of the wavelength of the light and so the question is what's the wavelength then? So the speed of light is frequency multiplied by wavelength and we know what the speed of light is in a vacuum and we'll assume that you know negligible difference in air where the radar is probably actually operating and we'll divide both sides by frequency to solve for λ. So we have 2.998 times 10 to the 8 meters per second divided by 500 times 10 to the 6 hertz which is 0.600 meters. So if there was a drone for example that had a size of less than half a meter then you would expect the radar to not be able to detect it.