Physics - Nuclear Physics (7 of 22) Half-Life of Nuclear Decay

[@RiyaTomar-jd3mw]

0:38 , how will it take a neutron in the nucleus and from where? Also how an electron can be converted to a proton. So, actually a beta particle is an electron or a proton? Does this conversion of electron to proton happens in every case?

[@MichelvanBiezen]

A beta particle is an electron that emanates from the nucleus. An electron cannot be converted to a proton.

[@karhukivi]

The half-life is really a mathematical concept to aid remembering the numbers as the decay constants are always very small, lots of decimals and negative exponents. It is the decay constant that is the fundamental value being measured. But the notion of half-life creates confusion for non-physicists as can be seen in the videos for C-14 dating. The usual question (or challenge) is that "nobody is living long enough to measure the half-life" - apart of course for those isotopes with half-lives of minutes to years duration.

[@MichelvanBiezen]

That doesn't mean that "half-life" is not a useful concept and has many good applications.

[@karhukivi]

@@MichelvanBiezen Non-physicists think that two half--lives equals a whole life. I always use depreciation as an explanation for decay constant, but we never talk about a car having a half-life, which with depreciation at 20% p.a. would be about 3.5 years. I can remember about a dozen half-life values but not a single decay constant, so yes, it is very useful for physicists!

[@pickensincorporated]

Thank you very much. Very helpful for my revision of A2 Physics. Greetings from the UK.

[@insanedrummer1572]

Question two: how do we know half life’s are constant? Are there examples where it isn’t?

[@MichelvanBiezen]

The half life of every radioactive element is constant and does not appear to depend on any external factors.

[@kosiokoye2384]

I fill 1/2^n should be amount in fraction remaining.... then to get amount remaining would be d fraction times initial amount

[@curtpiazza1688]

Great explanation!

[@MichelvanBiezen]

Thank you. 🙂

[@BadBoy-ls5vn]

The question that bothers me and i found no answer to it is how do any of us know tha half life of any element which is the constant of it like forcarbon 5700 years , how do we know how long it takes for any element to dacay into half ? Pls answer me sir

[@carlterencevaldellon]

Ra is for Radium not Radon. Ra should be Rn. Also, 232 should be 222. Radon-222 has the half-life of 3.82 days. Anyways, thank you for your videos. I find them very efficient and easy to follow.

[@MichelvanBiezen]

Thank you.

[@zuhabuha4766]

Sir you are treasure!

[@insanedrummer1572]

Does having more or less Carbon 14 affect the half life?

[@MichelvanBiezen]

No, the half life does not depend on how much carbon-14 you have.

[@manqobadlamini3264]

nice job ,sir

[@HaiderAli-nj7tv]

Sir could you please tell if half of the carbon is decayed in 5730 years why it is not fully decayed in another 5730? I have heard decay is independent of the neighbouring atoms or nucleus.

[@MichelvanBiezen]

Each carbon 14 atom has a certain probability of decaying. When you have a large nuber of them, together that results in 1/2 of the remaining carbon-14 atoms to decay in 5730 years. In the remaining half, again each atom has a certian probability of decaying such that in a sample half of them will decay in 5730 years, and so on.....

[@pspicerwensley]

Google should really let logged in users edit the captions as they really don't work well for technical transcripts. They're not bad but they're not good either...

[@opclass6168]

half life par video

[@pwghost]

thank you so much for these video's it very clear information.

[@TruthWillSF]

this is a geometric series

[@karhukivi]

A bit late with an answer! A geometric series would progress in jumps, like the bank deducting interest every month or week. Rather it is a continuous process and so is exponential. If the bank deducted the interest every hour, or every minute, it would approximate an exponential series.

[@TruthWillSF]

@@karhukivi 👍