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Nuclear Physics
Most commonly known for its applications in nuclear energy and nuclear weapons, Nuclear Physics also has applications in medicine and archaeology. This category is for questions about the branch of physics that deals with the study of the forces, reactions, and internal structures of atomic nuclei, Nuclear Physics.
3,164 Questions
When an atom splits it gives off what?
What species are given off when an atom "splits" depends on what causes the atom to split. There are four ways an atom can split: 1) Using a cyclotron or a syncrotron, some species traveling at very high velocity is collided into an atom. The atom may spit depending on the isotope of the atom used, the species it collides with and the velocity of the species. 2) Certain isotopes can capture a "slow" or "thermal" neutron after which the isotope will fission. 3) Certain isotopes are capable of splitting after being hit with a "fast" neutron. Slow neutrons must have a kinetic energy below a specific value, and fast neutrons must have a kinetic energy above a specific value. The kinetic energies required vary depending on the isotope capturing or being hit with a neutron. 4) There are a few isotopes that undergo spontaneous fission, meaning that they will fission without capturing or being hit with a neutron.
In case 1, if the atom splits, it and usually also the species with which it collides, disintegrates into at least two of the following species: isotopes with a smaller mass, subatomic particles and photons of electromagnetic radiation. For case 2, there are about nine or ten isotopes capable of capturing a slow neutron. These isotopes are named "fissile" isotopes, not to be confused with a "fissionable" isotope, which includes any isotope capable of undergoing nuclear fission regardless of the mechanism of the fission (not including fission caused in an atom smasher). Almost instantly after capturing a slow neutron, a fissile isotope becomes a new isotope of the same element, but with a nominal atomic mass of one AMU greater. The heavier isotope is unstable an immediately fissions into two lighter isotopes and releases at least one neutron plus ionizing radiation such as a gamma ray(s), beta particle(s) or an alpha particle(s). It is impossible to know what the two lighter isotopes are; one only knows the probability that the atom will split into two specific species. During the last approx. 70 years, socalled "fission curves" were emperically determined for the known fissionable isotopes. A fission curve is a graph that plots the mass of the fission products vs. the probability that a pair of specific lighter isotopes will be formed. In case 3, there are a handfull of isotopes that may split if they collide with a fast neutron traveling above a specific velocity. Each of these isotopes also has its own fission curve. Case 4 applies to the small number of isotopes that can split spontaneously, that is, without capturing or colliding with a neutron. Again, each of these isotopes have a specific fission curve.
It is important for someone who considers themselves a "Scientist" to know that only a very small fraction of all the isotopes are capable of "splitting," and, only if one of those isotopes disintegrates in a atomic accelerator, is the fissionable material in a "fast neutron" or a "fast flux" nuclear reactor, or is a constituent of a thermonuclear bomb. Lastly, a scientist should avoid using the word "split" when describing nuclear fission because that word implies that something hits an atom hard enough to cause it to break into pieces, and, in my opinion, causes most people to think that just about any atom will spit if it is hit hard enough by whatever. All 104 of the commerical nuclear power reactors in the USA, all the ones in Canada and in Europe, and probably in the rest of the world, operate by slow neutron capture by U-235 (and to a much lesser degree Pu-239) followed by nuclear fission. In other words, neutrons do not slam into U-235 or Pu-239 atoms breaking them into pieces.
All or virtually all commercial power reactors operate as follows: The nuclear fuel is a blend of uranium (238) oxide and uranium (235) oxide. Only about 0.7-2.5% of the uranium atoms are U-235, which is the primary isotope responsible for generating the heat that either causes the water in the reactor to boil or turns it into steam outside of the reactor vessel, depending on the design of the plant. A U-235 atom captures a neutron that has been slowed by normal water, heavy water (deuterium oxide, which is not radioactive) or graphite to form U-236. U-236 is an unstable isotope and breaks into two lighter isotopes, according to its fission curve, and releases an average of 2.4 neutrons. The entire process is incredibly fast, only taking a few nanoseconds to occur. Some of the neutrons from the U-235 fission go on to be captured by other U-235 atoms, however some of them must be captured to prevent a run-away chain reaction. Materials in the control rods are very efficient at capturing neutrons, and some plants add boron to the reactor water since boron is also efficient at capturing neutrons. Maintaining a nearly perfect balance that allows the right concentration of neutrons is necessary to keep the plant running.
Because of numerous automatic safety functions required in the USA, Canada and Europe, it is literally much more difficult to keep a plant running than to have an accident. If all of the nuclear operators just walked out of the control room, the plant would automatically shut down. The Three Mile Island accident was caused when improperly trained operators intentionally over-rode one or more automatic safety mechanisms. Even then, only a very small amount of tritium (H-3) was released from the plant, even though the reactor was ruined. Newer plants and all existing plants were designed or upgraded to prevent anyone from preventing or over-riding certain safety functions. The problem with Chernobyl was that the operators were performing some kind of unauthorized experiment that caused much of the water in the reactor to be lost. When they began to add water back into the reactor, the fuel was so hot that it caused the water to instantly turn to steam, and that caused a steam explosion that ruptured the reactor vessel. To make it worse, Chernobly was a graphite-moderated reactor, and without water and now with air able to enter the reactor, the graphite moderator ignited. None of the countries listed nor Japan has any graphite reactors.
After 50 years, 1500 g of actinium-227 will have undergone approximately 2.3 half-lives (50 years / 21.772 years per half-life). This means that approximately 25% (50% decayed after 1 half-life, and 50% of the remaining amount decays after the second half-life) of the original sample will remain radioactive, so there will be around 375 g of actinium-227 remaining.
How do the electric charges of alpha particles beta particles and gamma rays differ from each other?
From Physics Forums The alpha particle has a 2+ charge, beta has 1- charge, and the gamma is neutral (no charge).
The beta particle could also have a 1+ charge if it undergoes positron emission [a proton turns into a neutron and a positron (the "anti-electron")]
Is the mass of an atom uniformly distributed within the nucleus?
My God. NO! Protons and neutrons are in the central portion, called the nucleus, and electrons are in the outer part, forming shells around the nucleus. There is empty space between the nucleus and the electron shells.
What do you know about nuclear changes?
You are probably thinking of changes to a nucleus in nuclear reactions. This can be during radioactive decay, a nucleus emitting an alpha or beta particle is transmuted to another nucleus which defines it as a different element. Also during nuclear fission the nuclei of uranium or plutonium are split up and hence become other elements
How the forces between neutral atoms are formed?
Forces between neutral atoms are typically due to Van der Waals forces, which are weak and temporary electrostatic interactions between temporary dipoles in the atoms. These forces arise from fluctuations in electron distributions around the atoms, leading to attraction or repulsion between them, depending on the relative orientation of the dipoles.
What is the emission of electromagnetic radiation by an excited atom called?
The emission of electromagnetic radiation by an excited atom is called spontaneous emission. This process occurs when an atom transitions from a higher energy state to a lower energy state, releasing a photon in the form of electromagnetic radiation in the process.
What is the difference between nuclear fusion and sunspot?
Fusion is happening deep inside a star, not near its photosphere (commonly called the star's surface because we see it, a star is just a ball of gas contained by gravity and has no actual surface). The photosphere is just hot enough to glow in visible light. A sunspot is a colder area in the photosphere that does not glow as brightly (and thus looks like a dark spot) because of a sort of "magnetic storm" occurring there. Sunspots always occur in pairs: one a north pole and one a south pole. There is a magnetic flux loop connecting the pair and sometimes a solar flare following the flux lines. If the flux lines "brake" the flare will be ejected away from the star into space. These ejected flares cause the auroral displays, communications interruptions, and occasionally electrical blackouts.
What part of a nuclear reactor system contains uranium?
The fuel rods in a nuclear reactor system contain uranium. This uranium undergoes a nuclear reaction, generating heat used to produce electricity.
Nuclear fission can be safe when managed properly with appropriate safety measures in place. However, accidents such as Chernobyl and Fukushima have shown that there are risks associated with nuclear fission. It is important for strict regulations, inspections, and maintenance to be in place to ensure safety.
Who named the process by which materials give off energy of an uranium atom radioactivity?
The process by which materials give off energy from a uranium atom was named radioactivity by Marie Curie in the early 20th century. She discovered that certain elements, like uranium, emit radiation spontaneously.
What is an example of a homogenous mixture that is very evenly mixed?
A bottle of pure water is an example of a homogeneous mixture that is very evenly mixed. Each part of the solution contains the same concentrations of water molecules, resulting in a uniform composition throughout the entire mixture.
Why are protons converted into neutrons during positron emission?
Protons are converted into neutrons during positron emission to satisfy certain conservation laws, like charge and baryon number.
The following reaction takes place during positron emission:
p+ --> n + e+ + ve, where p+ is a proton, n is a neutron, e+ is a positron (antielectron), and ve is an electron neutrino.
Charge is +1 on both sides of the reaction, and so is conserved.
Baryonic number is 1 on both sides of the reaction (both the p+ and the n have baryonic numbers of 1), and so is conserved.
Also, lepton number is 0 on both sides of the reaction (e+ has a lepton number of -1 while ve has one of +1, thus adding up to zero), and so is conserved.
How the principle of conservation of energy is violated in beta decay?
In beta decay, a neutron decays into a proton, electron, and antineutrino. Energy appears to not be conserved because the initial neutron has more mass-energy than the resulting proton, electron, and antineutrino combined. However, this apparent violation is resolved by accounting for the kinetic energy of the particles involved and the energy carried away by the antineutrino, ensuring overall energy conservation in the process.
What is the relationship between plasma and nuclear fission?
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You can create a plasma reactor with a complete removal of fission systems.
Of course, my theory is not yet complete. But it is doable.
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Nuclear fission is a type of nuclear reaction in which the nucleus is?
Nuclear fission is a type of nuclear reaction in which the nucleus is split into two or more parts, releasing excess binding energy that is available due to the negative slope (for high mass nuclides) of the binding energy per nucleon curve. See the Related Link below for more information.
What was the element americium named after?
America, the country it was discovered in. Many elements are named after the country where they were first found.
What determines which radioactive element will give more accurate measurement of a rock's age?
By looking at the half-life of a radionuclide (as well as its chemistry), we can select which one will be best for determining the age of rock. The longer the half-life, the "farther back" in time we can measure to discover some things about when it originated.
What element does californium make when it emits an alpha particle?
When californium emits an alpha particle, it creates curium.
The results of beta transmutation will depend on which beta decay even occurs. If it's beta minus, a neutron will be converted into a proton and an electron will be ejected from the nucleus. The original atom with its 6 protons and 8 neutrons (6 + 8 = 14, the mass number as specified) will be an atom with 7 protons and 7 neutrons. In a beta plus decay event, a proton will be converted into a neutron and a positron will be ejected from the nucleus. The original atom with its 6 protons and 7 neutrons will be an atom with 5 protons and 8 neutrons. In addition to the ejected electron or positron, there will also be an ejected antineutrino or neutrino (respectively). Use the links below for more information on beta decay.
How do you calculate daughter in half life?
To calculate the number of daughter atoms present after a certain amount of time in a radioactive decay process, you would use the formula: N = N0 * (1/2)^(t/T), where N0 is the initial number of parent atoms, N is the number of daughter atoms, t is the elapsed time, and T is the half-life of the radioactive isotope. Simply plug in the values to determine the number of daughter atoms after the given time.
Paired forces are two forces that are equal in magnitude but act in opposite directions on an object. Examples include the force of gravity pulling an object downward and the normal force acting upward to balance it, or the tension in a rope pulling on an object and the equal and opposite tension in the object pulling on the rope.
