The alpha particles escape from the polonium nucleus.
The half life is related to random decay times.
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The more tightly bound a system is, the stronger the forces that hold it together.
By examining how tightly bound the nuclei are, we can learn about nuclear forces.
The rest mass can be used to determine the BE of a nucleus.
Einstein has a famous relationship with the two.
The smaller the mass of the nucleus, the more tightly the nucleons are bound together.
Energy is put into the system by work done to overcome the nuclear forces.
The binding energy BE is equal to the energy input.
The pieces are at rest when separated, and so the energy put into them increases their rest mass.
That mass increase is what it is.
Mass defect is the difference in mass.
It means that the nucleus's mass is less than the sum of its two main components.
We deal with the neutral atoms.
The atomic mass of the nuclide is given by adding electrons to the last equation.
The mass of a hydrogen atom is given by adding electrons to the protons.
The unified atomic mass units are expressed in Appendix A.
BE is calculated from known atomic mass.
The mass of the system is increased by the work done to pull a nucleus apart.
The binding energy BE is equal to the work to disassemble the nucleus.
In the nucleus, a bound system has less mass than the sum of its parts.
A puzzle created by radioactive dating of rocks is solved by radioactive heating of Earth's interior.
Small-scale physics can explain large-scale phenomena.
Radioactive dating can be used to determine the age of the Earth.
The oldest rocks on Earth solidified a long time ago.
Once the surface of the Earth cooled, these rocks solidified.
The temperature of the Earth can be estimated using the potential energy of the pieces being converted to thermal energy.
It is possible to calculate how long it would take for the surface to cool by using heat transfer concepts.
The result is a long time.
The age of the Earth is determined by how long the first rocks have been solid.
There is more than one type of evidence that supports this age.
The thermal energy is moved from the surface to the dark space by the Convection in the liquid regions.
It should have cooled to a lower temperature by now because of the age of the Earth.
Nuclear decay releases energy in the Earth's interior.
The cooling process has slowed because of this energy.
The interior of the Earth is liquid because of the waves produced by earthquakes.
Waves cannot travel through a liquid and cannot be transmitted through the Earth's core.
Waves can go through a liquid and through the core.
The temperature of the interior can be estimated from this information.
Since its formation, the interior should have cooled more from its initial temperature.
It should have been cool in no more than a few years.
Some of the primordial radioactive nuclides have unstable decay products that release energy.
The activity and energy contributed were greater early in the life of the Earth due to more of the primordial radioactive nuclides.
The amount of power created by decays is very small.
This relatively small amount of energy cannot escape quickly since there is a huge volume of material below the surface.
The power produced near the surface has a negligible effect on surface temperatures.
There is a final effect of trapped radiation.
When Alpha decay produces helium nuclei, they form helium atoms.
Most of the helium on Earth is obtained from wells.
The high thermal velocity of helium will cause it to escape in geologically short times.
BE is proportional to the number of nucleons in the nucleus.
Pulling apart a nucleus requires twice as much energy as pulling it apart.
The binding energy per nucleon is about 8 MeV, but is lower for the lightest and heaviest nuclei.
The nuclear force is 100 times stronger than the Coulomb force, and the nuclear force is shorter in range than the Coulomb force.
For low-mass nuclei, the nuclear attraction dominates and each added nucleon forms bonds with all others, causing heavier nuclei to have greater values.
This continues up to the mass number of iron.
New nucleons added to a nucleus will be too far away from other people to feel their nuclear attraction.
Since the Coulomb force is longer, added protons feel the repulsion of all other protons.
Nuclear attraction remains the same, but Coulomb repulsion grows for heavier nuclei.
This is the reason stable nuclei are heavier than protons.
A graph of binding energy for stable nuclei.
The attractive nuclear force has the greatest effect on the most tightly bound nuclei.
The binding energy per nucleon is reduced by the Coulomb repulsion at higher altitudes.
The spikes on the curve are bound tightly.
The nuclear force is stronger than the Coulomb force.
Each nucleon feels the nuclear attraction of all others.
The range of the nuclear force is smaller for a single nucleon in larger nuclei than it is for the nucleus.
The Coulomb repulsion can be added to overcome the nuclear attraction if the nucleus is large.
There are some noticeable spikes on the graph.
Confirmation that closed-shell nuclei are more tightly bound is one of the details revealed by these spikes.
The spikes show that some nuclei are tightly bound.
This finding can be linked to some of the elements.
The most common elements in the universe are hydrogen and, with much smaller amounts of other elements.
The most tightly bound nuclei are the most common elements.
One of the most tightly bound light nuclei emits light in decay.
The binding energy of the particle is calculated.
The first thing we need to do is find BE using the Equation.
We need to look up the appropriate atomic mass in Appendix A.
The binding energy per nucleon is large compared to other low-mass nuclei.
The chart of the nuclides shows that that is tightly bound.
It has less mass than other nuclei and can't spontaneously decay into them.
The binding energy helps explain why some nuclei decay.
Smaller mass in decay products can mean energy release.
Two protons and two neutrons in a nucleus can randomly find themselves together, experience the large nuclear force that binding this combination, and act as a unit within the nucleus, at least for a while.
In some cases, decay has taken place after the escapes.
There is more to be learned.
Energy production in stars and fusion and fission energy sources on Earth are dependent on the general trend in.
This application is covered in Medical Applications of Nuclear Physics.
The abundance of elements on Earth, in stars, and in the universe as a whole is related to the binding energy of nuclei and has implications for the continued expansion of the universe.
Identifying the unknowns will help determine exactly what needs to be determined in the problem.
You can decide whether the energy of a decay or nuclear reaction is involved, or if the problem is primarily concerned with activity.
A list of what can be inferred from the problem can be made.
Atomics are used for reaction and binding-energy problems.
The number of electrons involved must be counted since the neutral atoms are used.