Wavelength, Frequency, Period and Speed of Sound | Ultrasound Physics | Radiology Physics Course #2

Please note: I say speed of EM radiation doesn't change in different mediums. This is incorrect! However, in radiology physics we often assume the speed of electromagnetic radiation is constant despite minor material dependent speed changes, as these changes are imperceptible to our detector systems. Creating an ultrasound image relies heavily on accurately knowing the speed of sound; the production of radiographs and CT images do not rely on knowing the speed of electromagnetic radiation. Therefore, although not technically true, the comparison is often stated as electromagnetic radiation speed is constant and acoustic wave speed is variable (such as I've done in the video).

*High yield radiology physics past paper questions with video answers*
Perfect for testing yourself prior to your radiology physics exam 👇

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*I have also created two RADIOPAEDIA LEARNING PATHWAYS*

WHAT’S INCLUDED?
✅This YouTube series Ad free
✅Constantly updated Radiopaedia articles
✅Summary slides
✅Key take home bullet points throughout
✅Multiple review quizzes
✅Short answer review questions
✅Official Radiopaedia course completion certificate

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In the last talk we mentioned that the speed of sound changes depending on the medium through which it is travelling. The frequency of that sound wave remains the same. Here we will look at the elastic and inertial properties of the medium that will determine the speed at which sound travels.

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*Not sure if the question banks are for you?*
If you're here, you're likely studying for a radiology physics exam. I've spent the last few months collating past papers from multiple different countries selecting the most commonly asked questions. You'll be surprised how often questions repeat themselves!

The types of questions asked in FRCR, RANZCR AIT, ARRT, FC Rad Diag (SA), ABR qualifying Core Physics and MICR part 1 are surprisingly similar and the key concepts remain the same throughout. I've taken the most high-yield questions and answered them in video format so that I can take you through why certain answers are correct and others are not.

Happy studying,
Michael

#radiology #radres #FOAMrad #FOAMed

[thabangmoarabi]

The explanation and analogy of the running man made life really easy. Thanks once again.

[arminhejazian]

I have a bio-midecal image analysis this semester and WOW, your videos have been extremely helpful.

[fazaltahir]

Superb explanation, awesome series, much appreciated, thanks a lot
I m expecting next video series regarding MRI physics 😊

[julioriosortiz]

Amazing video as always. I appreciate the motion on your explanations, the correlation with your hand movements and the physics principle is really useful in my understanding.
Saludos desde Oaxaca, Mexico.

[samalmond]

Brilliantly clear analogy, thank you. I've recommended this series to the students i mentor. Thanks again.

[luffyc]

Of all the videos I had encountered your tutorials are the best - all are enlightening and easy to comprehend...thank you very much😊

[madchen.roentgen]

Wave equation (for sound and electromagnetic waves) is λ = V (velocity) / f (frequency).
I'd would have placed the letter "V" for velocity, instead of "C", since "C" is refering to speed of the light and it might be confusing since this lectures you're talking about sound. But besides that, this US tutorial is amazing. Expecting MRI and MRI sequences tutorial.

[christhomson]

I understand that we control the frequency of the waves produced by the ultrasound machine, and I understand how the wavelength of the sound wave can change as it moves through different media, but how can the frequency of the sound wave remain constant as it passes through the body while the wavelength changes? Are frequency and wavelength not dependent on each other?

[akramhusseinpour]

You're brilliant, really .
I wish you always be healthy and content.

[sooryaprakash]

Amazing video sir and wonderful explanation 👏👏👏. Please continue posting videos like this.

[dvsilencer]

"Unlike EM radiation, the speed changes depending on the medium through which that sound wave is traveling." --- Are you sure the speed of EM doesn't change depending on the medium? Because it should/does. Hence why there is c (speed of light in a vacuum), and then there is the speed of light through different materials. Or did you mean to suggest that the speed doesn't change MUCH compared to how much the speed of ultrasound changes through different media.

[asmaqasim]

Very good and informative lectures sir.. Thank you

[MohammadmoeinZanganeh]

lovely and enjoyable, thank you so much

[Nora-ticu]

If speed is doubled and frequency held consatnt wavelength will not change right?

[loanatanielu]

Thanks such a clearly explained video.

[snowpower-mlzk]

Thank u Sir
Your explanation is very clear .

[ivanmurillo]

What is driving me to think that muscle is more dense than water and, in that case, sound waves will travel faster in water compared to how fast/slow they move in MUSCLE? That is not the case, because sound waves travel faster in MUSCLE than in water, according to the video. How would you make it clear that water is much more dense than MUSCLE? I will appreciate your insight.

[jimboss]

Great videos but the bulk modulus is not independent of the density. There's a density term (rho) inside the bulk modulus: K = -V*(dP/dV) = rho*(dP/drho) :)

[tikpol]

These videos are awesome but the density elasticity thing is very confusing and different videos will say different things. Sound actually travels faster in humid air than dry air.