Nuclear Fission and Radioactivity - Part 1 of 3

Describes the process of radioactive decay and nuclear fission including the calculation of half lives.

[@DrPhysicsA]

Yes indeed. The purpose of the equation at 6:34 is to show how the charge and nucleon numbers balance. But for completeness, the anti-neutrino should be there too.

[@DrPhysicsA]

Yes. The atomic number or baryon number is conserved in radioactive decay. In beta decay it is conserved usually by a neutron being converted into a proton. It can happen the other way round in which case a positron is produced.

[@baidooish]

awesome teaching its like u have fun studying ..just for the heck of it i really enjoy ur videos

[@DrPhysicsA]

Anything that happens spontaneously in nature does so because it is energetically favourable (ie it will result in a lower energy level) So spontaneous radioactive decay will happen because the resulting decayed product will be at lower energy levels. But that begs the question why does not all spontaneous radiactive decay happen in an instant of time. That's where the weak force comes in. It's a rare event so it slows the process.

[@sayenshin]

Hello! Today, we... (*and 10 minutes of great explanations!)

[@reto-fassbind]

Thanks for all your great videos, I'm a big fan of yours. Correction @ 4:42 Please note that the atomic number as well as the mass number is written to the left to the chemical symbol, as the right side is reserved for the ionization state (upper right) and the number of atoms in compounds (lower right). I think it's worth an annotation as this mistake is not a peccadillo and is repeated throughout the video.

[@DrPhysicsA]

Thanks. Quite right. Total laziness on my part. I've added an annotation to make it clear.

[@DrPhysicsA]

Thanks. There are 2 videos on thermal physics in my "Thermodynamics" playlist. Hope they help.

[@ShaunRL]

If energy is conserved then mass is conserved, the mass of the system doesn't change, if the reaction takes place in a box and you weigh the box before and after the reaction the mass is the same. The mass of nucleus + particles given off doesnt = the mass before but the missing mass is in the kinetic energy of the particles given off. And this energy still contributes to the mass of the system.

[@lordpredator8855]

Great video

[@rajeshsahni4982]

a very good site for revision for A level physics

[@museandthekillers1]

In the Beta decay equation, would you not also have an anti-neutrino to balance it out? Great set of videos tho these really help!

[@TheCutiepie1993]

Really Great Video, so Helpful for Unit 5 Physics :)

[@ArbitraryZer0101]

Thanks very much for these videos. Have you done any or are planning to do any on thermal physics?

[@osmansokullu6137]

Carbon 14, beta decays to Nitrogen 14 with an emission of electron (beta particle) + electron neutrino. So the emitted electron is a result of neutron decay to proton. But if we consider the electrons Carbon have 6 and Nitrogen should have 7 electrons at their ground state. Where does this extra electron come from ?

[@muha0644]

this video was literally made before the higgs boson was discovered! It was in november of the same year IIRC

[@needsum12love]

Hey prof may i ask why atomic number is conserved in a radioactive decay? in the case of b-radiation is it still conserved?

[@sKhan-cu9fe]

Thank you so much

[@CptFroggy]

For the beta decay of uranium, where doe the two electrons are going to? Cause of uranium (92 protons), decays to Thorium (90 protons) and a (positive charged) beta particle. It looks like the charge is not neutral in this reaction.

[@DrPhysicsA]

+CptFroggy For alpha particle emission the atom will also need to lose 2 electrons - but there are free electrons all over the place so no problem with that.

[@pppppp9377]

I'm a bit late but why would it lose an electron to balance rather than want to gain an electron

[@pppppp9377]

I get it now

[@DanWright2012]

Mr denning??

[@MehulGawde]

zoshua colah