Particle Physics (29 of 41) What is a Photon? 13. Mie Scattering

[@julianjawadahmad1006]

You're one of the best educators on youtube.

[@MichelvanBiezen]

Thank you. Glad you found our videos! 🙂

[@Ameen_AAA]

I'm still learning from your channel every now and then since 2014. Huge respect and thanks.

[@MichelvanBiezen]

You are welcome. Glad you are still enjoying the videos. 🙂

[@rainerdbeck1960]

f should be replaced by lambda in the cos(r/f) and exp(-kr/f)

[@v1kh58]

In Mie Scattering formula, shouldn't it be "r/lambda", instead of "r/f". Because r/f is not dimensionless. And cosine of some dimensional argument doesn't make sense.

[@v1kh58]

BTW the explanation is really awesome

[@lam62sw]

This video is great!! And confusing, wish I wouldn’t have watched it first because Q from Mie Theory is typically extinction efficient not extinction coefficient (typically gamma). I was very confused until I could look up in a respected text book. This video is good but also a glossed over introduction so be-careful.

[@MichelvanBiezen]

Thanks for the feedback. 🙂

[@mkamalakkannan8327]

Appreciated, I too felt.

[@waelfadlallah8939]

Final question sir, that is bugging me a lot! How does the sun produces the different wavelength of light/radiation, now i know the sun produces the EM waves through beta decay but the issue here doesn't that mean we should receive a single wavelength since it's a single process of beta decay (on a large scale) or is it that through this mechanism we get all the wavelengths possible which brings me to my last inquiry which is, do these radiation travels towards us as a single superimposed wave or as discrete waves each with its own frequency ?!! I hope i didn't bother and also i send the right message.

[@MichelvanBiezen]

The Sun produces its copious energy through nuclear fustion reactions fusing hydrogen into helium via the proton-proton chain reactions. The energy produced then slowly migrates from the core to the surface taking an estimated several hundred thousand years. Near the surface this energy is converted into thermal motion of the outer layers of the Sun, which then cause the Sun to rediate E&M waves via the blackbody radiation, providing a range of wavelengths being emitted.

[@waelfadlallah8939]

@@MichelvanBiezen sir van Biezen, i can't thank you enough for answering both of my questions in a very professional and satisfying way. Bless you so so much!

[@MichelvanBiezen]

You are welcome. 🙂

[@ahmo356]

sir, i wanna ask you what can be the phase function (P(pi)) in rayleigh backscattering, in a micro wave area and the study particle is ammonium sulfate

[@鲨鱼辣椒-w7x-y6v]

Mr. Professor Mie Scattering of a single particle, is the scattered light distributed symmetrically around the incident light, that is, the scattered light is distributed exactly in a circle, do you agree with this point of view? This question has troubled me for a long time, I hope you can reply me, thank you！

[@MichelvanBiezen]

As shown in the video, it is particle size dependent. Mie scattering is a purely mathematical theory that tries to quantify the scattering off a speherical particle.

[@keppela1]

You've got both radius over frequency and radius over wavelength on the board. Is that right, or should all the equations be radius over wavelength??

[@houhoutrad8748]

You are right! I think for dimensional consistency, the ration in the cos must be dimensionless, so it must be the wave length

[@randyzhang528]

Very helpful, thank you. I want to ask a question. What is the mean of "k" in Mie scattering?

[@akshatpandey9141]

K is a constant.

[@akshatpandey9141]

Which represents the size of the particle.

[@heattransfer8003]

Hello sir. Where did you take these information? Like 1/10 lambda and all numbers? Is there any article?

[@MichelvanBiezen]

we can't remember what reference we used (we made that video too long ago).

[@hardikjoshi6125]

Hello sir, In video 3:00 you said in Mie scattering most of photon scattered in forward direction, and in example of car headlight @7:25 you mentioned most light reflected back because of mie sacttering.. Both statement cnflicting...

[@UmmUkashah]

Hardik Joshi yes, because the lights are from the front; if water droplets are in between you and the light sources, you received much more scattering than the light source itself. Your question helped me to digest this more. Thanks.

[@amdadulhoque9555]

Hi, can you please explain this more elaborately.

[@serathilsss]

+Michel van Biezen Thank you. but are there any relation between mie scattering with concentration of the particle?

[@MichelvanBiezen]

+serathilsss The amount of scattering as a function of distance traveled does indeed depend on the concentration of the gas or particles the radiation travels through.

[@sabbadini96]

Have you some articles about Mie Scattering and it's computation?

[@kalyanibrahma4057]

hello. in the graph is it the ratio of r/lambda × 1/10 or is it that r/lambda= 1/10 and varies upto, r/lambda= 1

[@MichelvanBiezen]

Yes, it is a range of values. (between 1/10 and 1)

[@kalyanibrahma4057]

Michel van Biezen .. thankyou, u saved my sleep tonight

[@shubhamsrivastava6028]

u explained well sir, for your next video only suggestion to improve is: keep notice of lights on white board..things u wrote on white board is not visible clearly in videos...might be because of too much scattering....

[@MichelvanBiezen]

Good suggestion. We have been experimenting with the lighting and with the newer videos we have figured it out.

[@maxfitlife]

Thanks for the lecture!

[@bsht123456]

thank you so much, very nice lectures!

[@SuperAliez]

Gracias! Thank you! I understand much better the Mie Theory.

[@TheBigBanggggg]

For me a rather non-intuitive explanation: the bigger the object light is scattered off, the more light is scattered forward? My brain can't handle that.

[@MichelvanBiezen]

We simply introduced what we observe. The "why" is the greatest challenge for all concepts in physics.

[@TheBigBanggggg]

@@MichelvanBiezen I understand. But this "why" is always around the corner with me. That makes Modern Physics quite a hard topic.

[@jakubkusmierczak695]

Mr. Professor when the temperature outside is decreasing especially in autumn, at night, we are able to see this phenomenon around the moon. Am I right? Orange halo.

[@MichelvanBiezen]

Mie scattering is particle size and photon wavelength dependent. Not so much on the temperature or time of year.

[@ayoublamsiah347]

Bonjour monsieur, Comment allez vous, bon j'espère que vous êtes bien,monsieur j'ai besoin des documentaires ou bien lives de l'équation de diffusion classique et quantique avec leurs démonstrations des conditions aux limites an et bn et cn et dn? Merci d'avance.

[@esh683]

if mie scattering is for particle size around wavelength why when we want write matlab code for wavelength 400-700 nm, we assume that particle radius is around 30-50 nm?????please answer me

[@joseiltonricardo]

Coloque legenda para português para que alcance mais pessoas.

[@MichelvanBiezen]

There are hundreds of different languages, so that would be a monumental task. (there is just the 2 of us). But can youtube do the translation? I believe that there is SW out there that automatically translates into any language as you listen to a video with another language.

[@muhammadfikrifansyuri4934]

very helpful, thank you

[@visionscience]

Very nice ..thank u

[@양예진-s4h]

Thank you so much sir.

[@mobinbahar8808]

bravo sir

[@aymanselmy2793]

thank you !!

[@_amit_kumar_946]

Nice I'm from india

[@MichelvanBiezen]

Welcome to the channel!

[@kalyanibrahma4057]

please please please please please please please answer somebody, anyone , Michael!! 👇