Zenarthra
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A bound system is at a lower energy level, does this have something to do with angular momentum?
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uberteknik
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(Original post by Zenarthra)
A bound system is at a lower energy level, does this have something to do with angular momentum?
Do not confuse the binding energy of electrons (ionisation energy) to the binding energy of the nucleus itself. They are not the same.

The Bohr-Rutherford model relates to the basic description of angular momentum for electrons orbiting in shells around the nucleus. It is represented by the shell designators 1s, 2s, 2p etc.

Nuclear binding energy derives from E=mc2.

The nuclear binding energy is that required to break the nucleus into it's consituent parts. The mass of any given atomic nucleus is always less than the sum of the mass of the unbound constituent parts.

i.e. mass has converted to energy during the unbinding process.

Nuclear decay is mediated by the weak interaction. i.e. neutrons converted to protons with a corresponding emission of beta- and anti-neutrino particles.
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Zenarthra
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(Original post by uberteknik)
Do not confuse the binding energy of electrons (ionisation energy) to the binding energy of the nucleus itself. They are not the same.

The Bohr-Rutherford model relates to the basic description of angular momentum for electrons orbiting in shells around the nucleus. It is represented by the shell designators 1s, 2s, 2p etc.

Nuclear binding energy derives from E=mc2.

The nuclear binding energy is that required to break the nucleus into it's consituent parts. The mass of any given atomic nucleus is always less than the sum of the mass of the unbound constituent parts.

i.e. mass has converted to energy during the unbinding process.

Nuclear decay is mediated by the weak interaction. i.e. neutrons converted to protons with a corresponding emission of beta- and anti-neutrino particles.
Why is a tighly bound nucleus at a lower energy state?
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uberteknik
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(Original post by Zenarthra)
Why is a tighly bound nucleus at a lower energy state?
If I am not mistaken, I think you asked the same question a few weeks ago?

How to tackle this?

You must first understand that A-level physics, takes the student to an understanding that is by no means perfect. This is because science (as yet) has no perfect explanation for some physical observations at the sub-atomic level.

For example, "Quantum Wierdness" is a good catch all phrase because at the sub-atomic level, there is no absolute answer. For instance with the wave-particle duality phenomena, particles behave in ways dependent on the method of observation and hence some people incorrectly make the assumption that the particle somehow 'knows' when it is being observed. This is plainly ridiculous. The answer is of course, we don't have a perfect explanation - yet.

Physics, as a science, observes behaviour and attempts to define the rules governing that behaviour. It's like peeling back the layers of an onion. We can get to a level of understanding like why chemical interactions behave the way they do. The answer is of course electrons and the electromagnetic forces between the electron and the nucleus of the atom that causes the observations we see in everday life.

The underlying nature of the atom then gets to the sub-atomic level which is a model that attempts to explain why atoms behave the way they do: electrons, protons and neutrons. Beneath that layer are a smorgasboard of sub-atomic particles and even more weird behaviour. That model is a work in progress. Cue experiments like the CERN particle accelerator, Fermi-lab et al.

Back to topic:

So it is with the fundamental observation for the conservation of both mass and energy in Einsteins famous equation E=mc2.

At A-level, you simply have to be content with the concept as currently stated. That, because of obeservations described so elegantly by Einsteins equation, mass and energy are conserved fundamental properties of nature. They are locked togther in a seemingly fixed ratio. Change one, and the other has to change to conserve the property. (Before anyone gets uppity, yes I know this does not hold true at relativistic speeds).

And observations hold that the bound atom has a lower mass than the unbound constituent particles. The lower mass is a result of the energy used to bind the nucleus together, which (according to Eisnstein) is because energy cannot be mass in that state. Energy is converted to mass during the unbinding process. i.e. the energy locked up in the bound state is converted to mass as the particle flies apart.

At this stage don't try to overthink it. Explanation is well beyond A-level and even then only to the limits of the standard model which is far from perfect. (Quite a few physics graduates struggle with same concepts too.)
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Zenarthra
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(Original post by uberteknik)
If I am not mistaken, I think you asked the same question a few weeks ago?

How to tackle this?

You must first understand that A-level physics, takes the student to an understanding that is by no means perfect. This is because science (as yet) has no perfect explanation for some physical observations at the sub-atomic level.

For example, "Quantum Wierdness" is a good catch all phrase because at the sub-atomic level, there is no absolute answer. For instance with the wave-particle duality phenomena, particles behave in ways dependent on the method of observation and hence some people incorrectly make the assumption that the particle somehow 'knows' when it is being observed. This is plainly ridiculous. The answer is of course, we don't have a perfect explanation - yet.

Physics, as a science, observes behaviour and attempts to define the rules governing that behaviour. It's like peeling back the layers of an onion. We can get to a level of understanding like why chemical interactions behave the way they do. The answer is of course electrons and the electromagnetic forces between the electron and the nucleus of the atom that causes the observations we see in everday life.

The underlying nature of the atom then gets to the sub-atomic level which is a model that attempts to explain why atoms behave the way they do: electrons, protons and neutrons. Beneath that layer are a smorgasboard of sub-atomic particles and even more weird behaviour. That model is a work in progress. Cue experiments like the CERN particle accelerator, Fermi-lab et al.

Back to topic:

So it is with the fundamental observation for the conservation of both mass and energy in Einsteins famous equation E=mc2.

At A-level, you simply have to be content with the concept as currently stated. That, because of obeservations described so elegantly by Einsteins equation, mass and energy are conserved fundamental properties of nature. They are locked togther in a seemingly fixed ratio. Change one, and the other has to change to conserve the property. (Before anyone gets uppity, yes I know this does not hold true at relativistic speeds).

And observations hold that the bound atom has a lower mass than the unbound constituent particles. The lower mass is a result of the energy used to bind the nucleus together, which (according to Eisnstein) is because energy cannot be mass in that state. Energy is converted to mass during the unbinding process. i.e. the energy locked up in the bound state is converted to mass as the particle flies apart.

At this stage don't try to overthink it. Explanation is well beyond A-level and even then only to the limits of the standard model which is far from perfect. (Quite a few physics graduates struggle with same concepts too.)

Ahh ok thanks.
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