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AM and FM radio waves are transverse waves that consist of electric and magnetic disturbances. These waves travel at a speed of 3.00 ×108 m/s. A station broadcasts an AM radio wave whose frequency is 1230×103 Hz (1230 kHz on the dial) and an FM radio wave whose frequency is 91.9×106 Hz (91.9 MHz on the dial). Find the distance between adjacent crests in each wave.
Reasoning
The distance between adjacent crests is the wavelength l. Since the speed of each wave is v=3.00×108 m/s and the frequencies are known, the relation v=fl can be used to determine the wavelengths.
Problem solving insight
The equation v=fl applies to any kind of periodic wave. |
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Solution
Notice that the wavelength of an AM radio wave is longer than two and one-half football fields!
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