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bsmm11
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Homework Statement
Explain why if your car is tuned to FM, it cuts out when you enter a tunnel but doesn’t if you are tuned to long wave reception.
(λ of FM: 3m, λ of long wave: 1500m)
Homework Equations
The Attempt at a Solution
Well, what I think is that..
As the λ of the long wave is much longer than the width of the entrance of the tunnel, there will be diffraction when the wave goes into the tunnel. Diffraction will cause destructive interference, and depending on the car's position there will be cut-out.
Therefore, I think FM should be the one with no cut out in the tunnel (which is of course contrary to my personal experience).
Please enlighten me. :shy: