# What is the cause of Radioactive Decay

Discussion in 'Physics & Math' started by RajeshTrivedi, Aug 7, 2017.

1. ### exchemistValued Senior Member

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Yes you are, if you ask if the Law of Inertia is obeyed. That law predicts a particle will continue in a straight line at constant speed, in the absence of a net force on it. It therefore says you can know exactly where it is at any time t and, as the speed is constant, you know its momentum exactly too.

QM says you cannot know both exactly, so you can't exactly define the evolution of its position with time or its speed.

As for "wave function" and "wave-particle" are different concepts, yes they are, but the wave function is the mathematical expression that underpins the wave-particle concept. So they are very closely connected. If you graph the wave function for atomic orbitals, you see a series of spherical harmonics. These are resonant standing wave patterns. They represent the allowed stable states of electrons in the atom because these are the only patterns that do not create destructive interference over time and thus vanish.

These are wave concepts, which describe the behaviour of so-called "particles".

Last edited: Sep 8, 2017

3. ### hansdaValued Senior Member

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I am not asking about momentum. I dont know why you are bringing momentum into the picture.

5. ### exchemistValued Senior Member

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Are you asking whether Newton's 1st Law (the "Law of Inertia") is obeyed, or not?

7. ### hansdaValued Senior Member

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See the question in the post #98.

8. ### exchemistValued Senior Member

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No. Don't be a prick and start playing games. This is important to clarify if you want an answer to the question you have asked me.

Are you asking whether this QM particle of yours obeys Newton's 1st Law?

Yes or no. It will cost you nothing to answer. I can deal with either response.

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10. ### exchemistValued Senior Member

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My point is that a QM particle cannot be said to follow Newton's 1st Law of motion BECAUSE that law implies that both speed and spatial location can be simultaneously known.

Do you understand what I am saying?

11. ### Dr_ToadIt's green!Valued Senior Member

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I have a counter-question: Why doesn't everyone who claims literacy know that?

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Know what?

13. ### hansdaValued Senior Member

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If QM particle does not follow Law of Inertia, It must be moving in a random fashion. Correct?

14. ### exchemistValued Senior Member

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No, random would imply completely arbitrary. In the case of the QM particle one can make mathematically precise statements about the probability of finding the "particle" within a certain envelope. That would not be the case it was moving entirely randomly. In fact of course the mathematical statement is the wave function, operated on by the appropriate QM operator. If one treats the QM entity as a wave, then the wave is well-described by the mathematics. It is only when you measure it that it has a probability of appearing as a particle in the envelope of space in question.

I think the hard thing to get hold of in QM is that the wave is just as "real" as the particle. We are all brought up on Newtonian physics which talks of "particles", so we are used to it. But when you think about it, a "particle" is a pretty artificial concept: a dimensionless theoretical entity with mass and another properties. How ridiculous! So in a sense I could have answered your question by saying, "What QM particle? - it's a wave!"

(I'm being a bit provocative but hope you will get my point.)

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