8. Radioactive Decay - Modes, Energetics, and Trends

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  • Опубліковано 4 гру 2024

КОМЕНТАРІ • 51

  • @mitocw
    @mitocw  4 роки тому +4

    To report potential content errors, please use this form: forms.gle/8B2zcUvfCtgJdTdE7

    • @LFTRnow
      @LFTRnow 2 роки тому

      Do you know why #9 is missing? I'm not seeing it in the playlist?
      Also, I've noticed the CC text is mostly correct but could use some help here and there, where should I post those suggestions? Alternately, I could probably edit the captions file for you now and then and email or upload it somewhere if you'd like help (no charge)?

    • @elijahdschultz
      @elijahdschultz Рік тому

      @@LFTRnowfrom the reference to “Amelia” at the end of this lecture, I believe Professor Short May have invited a guest speaker who did not consent to have her lecture published.

    • @matthewbartsh9167
      @matthewbartsh9167 11 місяців тому +1

      No. I'll just report them in the normal way: in the comments. Who do you think you are?

  • @Nellsus
    @Nellsus 4 роки тому +18

    Great lecture as always!
    I'd just like to point out that only charged particles can produce Cherenkov radiation, so it is the muons and electrons created by neutrino interaction that generates the Cherenkov radiation, and not the neutrinos themselves.

    • @kikoteixeira9199
      @kikoteixeira9199 3 роки тому

      #☺️pp0

    • @matthewbartsh9167
      @matthewbartsh9167 11 місяців тому

      How is it great when he made four huge errors in the first five minutes? Or do you think electrons have no mass, like he said?

    • @ehfik
      @ehfik 5 місяців тому

      @@matthewbartsh9167 do you teach at MIT?

    • @koenth2359
      @koenth2359 2 місяці тому

      ​​​​​@@matthewbartsh9167 He said 'with no mass' in the context of writing up the nucleon number (which is referred to as the 'mass number' of a nucleus, it's never exact except for 12C, but for a single nucleus it's about an integer times u). The mass of an electron is only 1 /1840 u. So yes, the electron has mass, and of course he knows that, but the written 0 is correct, and I'd say the slip of the tongue there is forgiveable.
      For the pedantic: even the (anti)neutrino has mass, he mentioned that when writting the 0.
      I spotted a somewhat bigger mistake when he wrote a 0 for the charge number. He called it 'the number of protons' which is actually 0, but that's not what the notation means. He should have written '-1' to the lower left of the β. In his equation charge is not conserved.
      Good teachers use little white lies for educational purposes. Only the most excellent teachers, like RPF are always explicit about their white lies, doing so without distracting the pupils too much from the main message.
      I'm not botherd too much by the small mistakes because it's not so hard to see through them. I think it's a great lecture and I learned something from it. Planning to check out the rest of the course.

  • @ShanetheTutor
    @ShanetheTutor Рік тому +1

    This is my favorite MIT OpenCourseWare series. Great instructor!

  • @1080pMarco
    @1080pMarco 2 роки тому

    The very final sketch is definitely something. The guy never disappoints, and so his great lectures.

  • @CenTexTom
    @CenTexTom 2 роки тому +2

    Another excellent lecture by Dr. Short, very Interesting...this is definitely taking Chemistry, Mathematics and Physics to the next level and as Loverboy would say "I'm loving every minute of it"

  • @jacobjohn378
    @jacobjohn378 3 роки тому +3

    48:20 had a huge laugh. Awesome lecture.

  • @krheadset7438
    @krheadset7438 3 роки тому

    3:26 though XDd that eye move was just so cutie

  • @davidwright5719
    @davidwright5719 3 роки тому +10

    There is an error in this lecture. Neutrinos do not produce Cherenkov light, even at speeds above the speed of light in a medium, because they do not interact electromagnetically. (Also, if they did, neutrino detectors would be drowning in events, because oodles of neutrinos cross them every second.) Cherenkov rings are only produced in the rare case that a weak interaction converts a neutrino to an electron, which then produces detectable Cherenkov light.

    • @Ergzay
      @Ergzay Рік тому

      That's equivalent to saying that the neutrino produced it however.

    • @matthewbartsh9167
      @matthewbartsh9167 11 місяців тому +1

      There isn't just one error in the lecture. There are four errors in just the first five minutes (all I've watched). Or do you agree with him that an electron has no mass?

    • @temporaryphase
      @temporaryphase 3 місяці тому

      ​@@matthewbartsh9167The rest mass of the electron is 9.1093837015 × 10−31 kg, which is only 1/1,836the mass of a proton. An electron is therefore considered nearly massless in comparison with a proton or a neutron, and the electron mass is not included in calculating the mass number of an atom.

  • @MeriaDuck
    @MeriaDuck 2 роки тому +1

    Love the 'approximately exactly'

  • @BringJoyNow
    @BringJoyNow 3 роки тому +1

    48:20 Not the first time I heard of, surely not the last time I laugh about the correct answer

  • @lucashuss9075
    @lucashuss9075 9 місяців тому

    fantastic video, Does anyone have an answer to the number of antineutrinos vs energy question, I believe that as T -> Q the number of antineutrinos would obviously decrease to 0, maybe its an inverse linear relation between T and # of anti neutrinos?

  • @VeteranVandal
    @VeteranVandal 2 роки тому +2

    Eat the gamma, put the alpha in the pocket, beta arms length away and give the "friend" the neutrons.

  • @matthewbartsh9167
    @matthewbartsh9167 11 місяців тому

    3:53 He says, "They are kind of indistinguishable." What kind of work does "kind of" do here? Are they, strictly speaking, distinguishable?

    • @sashimanu
      @sashimanu 4 місяці тому

      They can be distinguished by their energy levels with some a priori knowledge about the possible emitters

  • @iuliannita8357
    @iuliannita8357 Рік тому +2

    lesson 9 is missiong from youtube...please add it... tks

    • @mitocw
      @mitocw  Рік тому +3

      Sorry, lecture 9 is not available.

    • @iuliannita8357
      @iuliannita8357 Рік тому +3

      @@mitocw thanks anyway for all other lectures shared

  • @andrewmaxfield5873
    @andrewmaxfield5873 2 роки тому

    my man loves his (zirconium?) rod. And I fuckin love his teachings. Grateful to be able to listen to this. this is amazing!

  • @l.gagnon3846
    @l.gagnon3846 Рік тому

    Thank you for your wonderful lectures! There is something that I don’t understand: the main beta decay for Co60 shows 317kV. This is less than the mass of the electron(511kV). How do you explain this?

    • @pialamode
      @pialamode Рік тому +2

      The energy listed in decay diagrams is always the kinetic energy of the electron. This is just a convention because the mass of the electron is constant so you can work backwards to get the total mass-energy.

    • @l.gagnon3846
      @l.gagnon3846 Рік тому

      Thank you for answering!

    • @l.gagnon3846
      @l.gagnon3846 Рік тому

      Thank you for answering!

    • @l.gagnon3846
      @l.gagnon3846 Рік тому

      Thank you for answering!

  • @Ikbeneengeit
    @Ikbeneengeit 4 роки тому

    Another great lecture, thanks. Why do we see some specific decay types more than others? E.g. why is proton emission is much rarer than alpha decay?

    • @skuamato7886
      @skuamato7886 3 роки тому +4

      Also just a student here but from what the prof said I'd guess the reason is an alpha particle in itself is much more stable than a single proton and is therefor easier to exist on its own

  • @rishiravi6621
    @rishiravi6621 3 роки тому

    Thanks for your teaching sir please addsome information about nuclear physics

  • @oussamamounouar5655
    @oussamamounouar5655 2 роки тому

    Aren't Beta particles supposed to have a -1 to count for the charge, and that goes for B+ as well with a +1. I know it's obvious but still, it bugged me on that board. Hope someone from 2022 is watching.

    • @l.gagnon3846
      @l.gagnon3846 Рік тому

      When there is no sign, it is -1 by convention

  • @shivang581
    @shivang581 4 роки тому +8

    This is America

    • @matthewbartsh9167
      @matthewbartsh9167 11 місяців тому +1

      What's that supposed to mean, and why are people giving it likes?

  • @matthewbartsh9167
    @matthewbartsh9167 11 місяців тому

    4:09 He says, "an electron, with no mass". There is no such thing as an electron with no mass. Two errors already. And not one of the students put his hand up and asked about it. So much for MIT. I heard that being woke is the main goal there.

  • @reginaturnip
    @reginaturnip 2 роки тому

    my english so bad :(

  • @zack_120
    @zack_120 Рік тому

    Doubting this is really American

  • @matthewbartsh9167
    @matthewbartsh9167 11 місяців тому

    5:39 Why hasn't he explained why he is drawing the nuclei/nuclides as horizontal lines. Why did he mumble so that I could not hear what he claimed was a matter of conservation thirty seconds ago? Four huge teaching errors including one statement (that electrons have no mass) that is flat wrong, as an intelligent ten year old would know, so far. Astoundingly poor teaching. Not worth watching, let alone paying MIT fees to watch. Pity the poor students. I guess they aren't allowed to question anything the teacher says.

    • @temporaryphase
      @temporaryphase 3 місяці тому +2

      He explained in an earlier lecture that the Mass is so miniscule it's not included on the total atomic mass
      As per "The rest mass of the electron is 9.1093837015 × 10−31 kg, which is only 1/1,836the mass of a proton. An electron is therefore considered nearly massless in comparison with a proton or a neutron, and the electron mass is not included in calculating the mass number of an atom."

    • @matthewbartsh9167
      @matthewbartsh9167 3 місяці тому

      @@temporaryphase If so, he should have said they have *negligible* mass, not that they are massless. Excuse not accepted.