Does amplitude change when passing through a new medium?

[rskhan29]

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For a mechanical wave that passes from two substances with different density, I know that wavelength changes and so does velocity while frequency remains constant. But does amplitude of the wave change? I'm going to guess yes, because a denser substance has more inertia and is thus likely to be less displaced. Can someone give a definite answer?

 

[Kaustikos]

For a mechanical wave that passes from two substances with different density, I know that wavelength changes and so does velocity while frequency remains constant. But does amplitude of the wave change? I'm going to guess yes, because a denser substance has more inertia and is thus likely to be less displaced. Can someone give a definite answer?

Examkrackers has an excellent explanation about this that helped me understand it. For your sake; yes the amplitude does change. If you don't have EK, then I'll try to explain it.

Basically, when a wave changes medium, part of it goes through the medium and part of it is reflected back. Since not all of the wave goes through, not all of the energy is transferred. Amplitude is directly related to energy. Thus - less energy = lower amplitude. The amount of wave that goes through the medium is dependent on how different the medium is to the original medium (some can even totally reflect the wave).

 

[AsuKa]

to add to the excellent explanation above, yes it does change.

when sound goes through a solid, it travels faster than it goes through air.

and the general formula for waves is: velocity = frequency * wavelength

v=f lambda

because the velocity changes, then either the frequency or the wavelength must change.

frequency stays constant, wavelength changes 🙂

 

[BlackSails]

frequency stays constant, wavelength changes 🙂

Wavelength != amplitude.

 

[AsuKa]

**** youre right, im talking about something totally diff 🙂

teaches me not to make posts at 2 am 🙁