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Both positron and electron are of equal mass i.e about 9.1*10^-31 kg .
The speed of light is about 3*10^8 m/s, and as per Einstein's theory E=m*c*c .
Total mass = 2*9.1*10^-31 and c*c = (3*10^8)^2 = 9*10^16.
So, energy released = 2*9.1*10^-31*9*10^16 = about 1.637*10^-13 joules, or about 1.02 MeV.
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What is pair production?
Pair production is the transformation of electromagnetic energy into matter, into a particle and its antiparticle, usually an electron and a positron. Let's have a look at this situation. When a high energy gamma ray with a minimum energy of 1.022 MeV passes close to an atomic nucleus, a phenomenon called pair production can occur. In this event, the energy of the gamma ray is converted into mass. It's a play right out of Albert Einstein's quantum mechanical playbook. The electron and positron are opposites of each other, and the appearance of an elementary particle and its antiparticle must obey conservation laws. That's where the "assistance" of a nearby atomic nucleus comes in. The electron and positron will appear and come away from the event with some given kinetic energy, and will scatter and slow down as they move off. The positron, of course, will end up combining with an electron in a mutual annihilation event where the two particles have their mass entirely converted into energy. This will result in a pair of electromagnetic rays, or photons, leaving the annihilation event and moving in opposite directions.
What is the minimum charge on an object?
The minimum charge on an object is the charge of an electron, which is approximately -1.6 x 10^-19 coulombs.
What is the work function formula used to calculate the minimum energy required to remove an electron from a material?
The work function formula is given by: ( textWork Function textEnergy of Incident Photon - textKinetic Energy of Ejected Electron ) This formula is used to calculate the minimum energy needed to remove an electron from a material.
What is the work function equation used to calculate the minimum energy required for an electron to escape from a material?
The work function equation is: ( textEnergy textWork Function textKinetic Energy ). It calculates the minimum energy needed for an electron to escape from a material.
How is a positron produced?
A positron is created in a pair production event or in beta+ nuclear decay (which is called positron emission). It (the positron) appears "out of nowhere" with an associated electron under certain conditions in pair production. And in the nuclear decay schemes of some radionuclides, it is generated spontaneously within the (unstable) nucleus and exits that nucleus in the decay event. Curious? Let's look further.In positron emission (beta+ decay), a proton in an atomic nucleus experiences a change mediated by the weak interaction (the weak force), and one of its up quarks is transformed into a down quark. The change results in the "conversion" of a proton into a neutron. This causes atomic number to go down by one because there is one fewer proton in the atomic nucleus than just before the event. Here's an example:In the beta plus decay of carbon-11, a new element, boron-11, is created. A positron, a neutrino, and a gamma ray will be ejected from the nucleus. Here's the equation for it:6C => 5B + e+ + ve + 0.96 MeVAn atom of carbon becomes an atom of boron. The e+ is the positron and the ve is the neutrino. The gamma ray has an energy of 0.96 MeV (million electron-volts). There aren't many nuclei that do this. It is only seen in carbon-11, potassium-40, nitrogen-13, oxygen-15, fluorine-18, and iodine-121. That's it. Beta+ decay isn't all that tough to understand. What about pair production?Pair production is the "making" of a positron and an electron out of a high energy gamma ray. Both pair production and beta plus nuclear decay occur naturally, so the positron can be said to occur in nature. Remember that the positron is an antiparticle - it's antimatter - and it will, after appearing, slow down via scattering and will eventually combine with an electron in mutual annihilation. The positron has a short mean lifetime and a short mean path of travel. They usually don't last long after they're created. But lets look at the creation of the particle pair.The energy of the photon that creates the electron pair must have must meet a minimum threshold. And the threshold energy necessary for this even to be possible is 1.022 MeV. That's a lot of energy, and all that energy will be converted into mass - the rest mass of the electron and the rest mass of the positron. Higher energy gamma rays might still initiate pair production, but the extra energy would be accounted for in the kinetic energies of the pair of particles produced.A gamma ray of sufficient energy passes near an atomic nucleus and the pair is produced. Note that pair production is not the spontaneous "option" that high energy gamma rays have. The photons must pass close by an atomic nucleus for there to be a probability that pair production will occur. This is because momentum must be conserved, and the "assisting" nucleus will handle this chore.We should also note that researchers using high powered lasers on gold target material are able to produce considerable quantities of positrons for research, and this work is continuing. Links are provided to associated Wikipedia articles and related questions.
What is the definition of annihilation in physics?
the conversion of matter into energy, especially the mutual conversion of a particle and an antiparticle into electromagnetic radiation.Above is the definition, that is given for annihilation, on Google.The positron and electron annihilate into two gamma rays.As per the equation of Einstein, you have E = m * C square.Now that the mass of electron and positron is same. So you put the mass of both into the formula.You get 2 E = 2 m * C square.You divide this equation by 2.You get, E = m * C square.That means from one positron, you get one gamma ray.That means from one electron, you get one gamma ray.That means from one gamma ray, you get one electron.That means from 2 gamma rays, you get 2 electrons.( Just multiply the equation by 2.)(Here C is the speed of light. It is very high figure. The square of the speed of light is too high a figure.it's about 300,000,000 m/s. The square of 300,000,000 comes to be 90,000,000,000,000,000.)The electron is supposed to be the smallest mass in the atom. The photon emitted is supposed to be the smallest unit of energy. So if you multiply the one electron by the figure 90,000,000,000,000,00, you get minimum 90,000,000,000,000,000 photons emitted. From the positron also you should get the same amount of energy got released. Gamma ray is high frequency photon emitted. Only two gamma rays are emitted. "Two gamma rays are produced out of the mass of two electrons (or positrons) into energy" is the most not so wise statement I have ever encountered.So the mass to energy ratio just does not match.So either the equation of the Einstein is wrong, or the definition of the annihilation is wrong.Here the definition of annihilation is wrong.The fact is that mass get destructed into nothing in case of annihilation. The gamma rays come from the kinetic energy of the electron and positron. Mathematically one of the two gamma rays is anti-gamma ray and other is gamma ray.It comes that mass of the electron is plus m. The mass of the positron is minus m.The plus m + minus m = 0.So from zero, you get positron and electron.So from zero you get matter and anti-matter.Hence proved.
What is pair production?
Pair production is the transformation of electromagnetic energy into matter, into a particle and its antiparticle, usually an electron and a positron. Let's have a look at this situation. When a high energy gamma ray with a minimum energy of 1.022 MeV passes close to an atomic nucleus, a phenomenon called pair production can occur. In this event, the energy of the gamma ray is converted into mass. It's a play right out of Albert Einstein's quantum mechanical playbook. The electron and positron are opposites of each other, and the appearance of an elementary particle and its antiparticle must obey conservation laws. That's where the "assistance" of a nearby atomic nucleus comes in. The electron and positron will appear and come away from the event with some given kinetic energy, and will scatter and slow down as they move off. The positron, of course, will end up combining with an electron in a mutual annihilation event where the two particles have their mass entirely converted into energy. This will result in a pair of electromagnetic rays, or photons, leaving the annihilation event and moving in opposite directions.
What is the minimum gamma ray energy needed to produce a positron?
The minimum photonic energy required to create an electron-positron pair is 1.022 MeV. This energy is the equivalent of the rest masses of the pair of particles created. There is a bit more to this, as conservation of momentum must be observed. Pair production will occur, when it occurs, in the vicinity of an atomic nucleus when a high energy gamma ray zips in. The nucleus provides some "help" to "balance the equations" that describe the event, and that atomic nucleus will allow symmetry to be preserved. Specifically, that atomic nucleus acts in the conservation of momentum. That's why pair production won't occur as gamma rays are flying through the vacuum of space; there are (virtually) no atoms out there to facilitate the event. It may sound complex, but it's not all that difficult to get a handle on the phenomenon. A link is provided to our friends at Wikipedia. Knowledge there is free, and pair production isn't all that tough to understand. The article is brief and readable, and the complex equations that might have been posted are absent. Check it out.
Why is it that sometimes when a very high energy electron hits a target material a positron and two or more electrons come out of the event?
An electron at high energy entering into a scattering event will bring all that energy with it. All that energy will have to be "dealt with" in the outcome. One way that a big chunk of it can be "handled" is almost magical. A large portion of the energy can be transformed into an electron-positron pair. This event is called pair production. We usually see it when a high energy gamma ray causes it, but it can be one of the outcomes in an energetic electron collision. The production of this pair of particles is the direct result of the conversion of energy into matter, and it will carry off a lot of the energy in the event. The minimum energy need to create the pair is 1.022 MeV. The original electron is still "in one piece" after the event, so it may look like the single electron crashed into a target and two electrons and a positron came away. It was actually the original electron and that electron-positron pair. If the original electron ionized another electron (or more) in the target material (which is possible), they will come away as well. Certainly there are a number of possible outcomes in an energetic electron scattering event, but pair production is one of the possible outcomes, depending on the energies involved and the target material.
What is the minimum energy to produce ionization?
The minium required energy of a photon that is involved in the creation of an electron-positron pair (which is pair production), is 1.022 MeV.An electron-positron pair has a given probability of being produced when a photon of the stated energy (or a higher energy) passes close the nucleus of an atom. Pair production does not happen "in the presence of a photon" but happens as a direct result of the the actual presence of a photon (having at least the stated energy) in the presence of an atomic nucleus. The presence of an atomic nucleus is necessary to insure conservation of the quantum mechanical characteristics of the event. Said another way, the high energy photon alone cannot spontaneously create the electron-positron pair in pair production. A link can be found below to related questions.
Definition of electron affinity?
The energy change that occurs when an electron is added to a neutral atom. This is usually exothermic. Noble Gases are excluded from this. Equation: X(element)+e-(electron)---------> X-1+ energy
What is the minimum charge on an object?
The minimum charge on an object is the charge of an electron, which is approximately -1.6 x 10^-19 coulombs.
What is the work function formula used to calculate the minimum energy required to remove an electron from a material?
The work function formula is given by: ( textWork Function textEnergy of Incident Photon - textKinetic Energy of Ejected Electron ) This formula is used to calculate the minimum energy needed to remove an electron from a material.
What is the work function equation used to calculate the minimum energy required for an electron to escape from a material?
The work function equation is: ( textEnergy textWork Function textKinetic Energy ). It calculates the minimum energy needed for an electron to escape from a material.
How is a positron produced?
A positron is created in a pair production event or in beta+ nuclear decay (which is called positron emission). It (the positron) appears "out of nowhere" with an associated electron under certain conditions in pair production. And in the nuclear decay schemes of some radionuclides, it is generated spontaneously within the (unstable) nucleus and exits that nucleus in the decay event. Curious? Let's look further.In positron emission (beta+ decay), a proton in an atomic nucleus experiences a change mediated by the weak interaction (the weak force), and one of its up quarks is transformed into a down quark. The change results in the "conversion" of a proton into a neutron. This causes atomic number to go down by one because there is one fewer proton in the atomic nucleus than just before the event. Here's an example:In the beta plus decay of carbon-11, a new element, boron-11, is created. A positron, a neutrino, and a gamma ray will be ejected from the nucleus. Here's the equation for it:6C => 5B + e+ + ve + 0.96 MeVAn atom of carbon becomes an atom of boron. The e+ is the positron and the ve is the neutrino. The gamma ray has an energy of 0.96 MeV (million electron-volts). There aren't many nuclei that do this. It is only seen in carbon-11, potassium-40, nitrogen-13, oxygen-15, fluorine-18, and iodine-121. That's it. Beta+ decay isn't all that tough to understand. What about pair production?Pair production is the "making" of a positron and an electron out of a high energy gamma ray. Both pair production and beta plus nuclear decay occur naturally, so the positron can be said to occur in nature. Remember that the positron is an antiparticle - it's antimatter - and it will, after appearing, slow down via scattering and will eventually combine with an electron in mutual annihilation. The positron has a short mean lifetime and a short mean path of travel. They usually don't last long after they're created. But lets look at the creation of the particle pair.The energy of the photon that creates the electron pair must have must meet a minimum threshold. And the threshold energy necessary for this even to be possible is 1.022 MeV. That's a lot of energy, and all that energy will be converted into mass - the rest mass of the electron and the rest mass of the positron. Higher energy gamma rays might still initiate pair production, but the extra energy would be accounted for in the kinetic energies of the pair of particles produced.A gamma ray of sufficient energy passes near an atomic nucleus and the pair is produced. Note that pair production is not the spontaneous "option" that high energy gamma rays have. The photons must pass close by an atomic nucleus for there to be a probability that pair production will occur. This is because momentum must be conserved, and the "assisting" nucleus will handle this chore.We should also note that researchers using high powered lasers on gold target material are able to produce considerable quantities of positrons for research, and this work is continuing. Links are provided to associated Wikipedia articles and related questions.
Which is the substance having minimum mass in the world?
answer is one electron..........its mass is about 9.109*10 power -31
What is a work function?
A work function is the minimum amount of energy required to remove an electron from a solid to a point just outside its surface. It is essentially the energy barrier that needs to be overcome for electrons to be emitted from a material.
