Ultasound

[RH8448]

When ultrasound is used what exactly can occur to the sound waves. I did a Khan Academy problem and the "right" answer is suspicious because it says wavelength changes while frequency doesn't change after absorbing into tissue. This wouldn't make sense. So, the question asks whether speed and/or frequency change during the process of an ultrasound. Any insight? Thank you

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[Medgrant]

If wavelength changes, then the frequency would also change according to: f=V/ lambda. I'm assuming they stated frequency doesn't change at the source. Anyone feel free to correct me.

 

[Cawolf]

Frequency is a property of the wave at production and will generally remain constant through changes in medium.

The velocity of the wave will change, and the wavelength will change proportionally while frequency remains constant.

 

[Blueprint MCAT Tutor]

You hold your ear up to a door to eavesdrop on the people inside. Their voices will be muffled, but not weirdly higher pitched or lower pitched. We perceive pitch as frequency, and the pitch/frequency of the wave remains the same.

Yet we also know that sound speeds up going air > solid so that means that wavelength must change. So v goes up, as does lambda.

That's the example I always remember to keep this straight. Good luck!

 

[Medgrant]

Frequency is a property of the wave at production and will generally remain constant through changes in medium.

The velocity of the wave will change, and the wavelength will change proportionally while frequency remains constant.

Makes total sense now. Not sure why I didn't think of the mediums changing velocity. I better review my 5th grade physics haha