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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
Is velocity of electrons increase by increasing voltage?
Depends on what is between the potential difference (ie, the voltage).
If it's an evaculated tube, and the electrons are travelling between the anode and the cathode without much interference, then then a higher voltage will mean that the electrons arrive with more kinetic energy -- ie, increased velocity.
However, if there's a wire between the two voltages, then the drift velocity of the electrons (which is pretty slow to begin with) does not increase, but only the number of electrons that are drifting.
How can pathology affect the image in terms physics on medical ultrasound?
Some pathology will affect the image on medical ultrasound because it will reflect or absorb sound waves differently from the surrounding tissue, making a light or dark image on the screen that makes the pathology visible.
Why doesn't storing a radioactive source in a freezer stop radiation from being emitted?
Because radioactivity is a naturalphenomenonthat is independent on any external conditions of temperature,pressure,humidity, ... etc.
A nuclear fission process in which neutrons produced by fission trigger more fissions?
nuclear chain reaction
Note: there are also chemical chain reactions (e.g. polymerization), of course they involve no neutrons
What is the nuclear reaction for alpha decay of Radium-226?
Since an alpha particle is a helium-4 nucleus, the resulting atom has an atomic mass that is 4 less, so 226 minus 4. Also, to get the element, look up the element number for radium, and subtract two from that.
Why do some researchers complain when the emission of a gamma particle is called gamma decay?
Because its not a decay process. Gamma is an emission of energy in the form of photons from the nucleus when the nucleus changes from one energy level to a lower energy level. It is true that this is often preceded by a decay event, such as alpha or beta, but it is a distinct, non decay, event.
A reaction to obtain hassium is:
Pb-208 + Fe-58-------------Hs-265 + n
Can one neutron can split into an alpha particle and a beta particle?
No, this is not possible. There are multiple reasons one could give for this.
For example electric charge is not conserved; the neutron has no charge, the beta particle has a charge of -1 (times the positive elementary charge) and the alpha particle has a charge of +2. Therefore you go from 0 charge to (-1 + 2 = 1) +1 charge. You could fix this by making two beta particles (but it would still not work for the reasons below).
Every such reaction must conserve baryon number. A baryon is an object consisting of three quarks. The neutron is a baryon and therefore has baryon number +1. The alpha particle consists of two neutrons and two protons (the proton is also a baryon) so it has baryon number +4. The beta particle has baryon number 0. So the reaction n -> alpha + beta would increase the total baryon number by (+4 - 1 = 3) 3 which is not allowed. To fix this one would need, for example, to add three baryons to the initial state.
The lepton number is also not conserved by this reaction. Protons and neutrons both have lepton number 0, but the beta particle has lepton number +1. Therefore this reaction would go from lepton number 0 to +1, which is also not allowed. This could be easily fixed by adding an antielectron-neutrino to the final state.
A possible reaction that would fix everything would be something like:
4n -> alpha + 2 beta + 2 antielectron-neutrinos
Why was the Higgs boson named after Peter Higgs?
Peter Higgs is credited with first proposing the existence of the Higgs Field, an idea that resulted in a unification of the electro-magnetic force with the weak interaction. Peter did not name the field after himself, that came later.
Is it true that Unlike protons or neutrons electrons have no mass?
no electrons have mass, about 1/1800 that of a proton or neutron.
its called a beta particle, but its an electron
What is the lightest element having naturally occurring isotopes that undergo alpha decay?
Samarium-146 is the lightest element found naturally on earth to undergo Alpha emission. There are no accompanying gamma radiations.
Source: Chemistry: The Practical Science, Volume 10 By Paul B. Kelter, Michael D. Mosher, Andrew Scott
Tellurimum- 106 to 110 will be the answer if artificially made isotopes are included.
A fermi gas is a model from quantum mechanics first proposed by Fermi. A neutron star is said to be an example of a Fermi gas, and that would indeed be a dangerous place.
Why do nuclei that emit alpha particles such as americium-241 are safe to use in smoke defectors?
Actually, americium-241 is not safe.
If you disassemble the smoke detector and remove the americium-241 pellet, and then ingest it, you are at risk of developing cancer, because an alpha emitter is dangerous when ingested. There are clear warnings on the smoke detector about this.
The reason smoke detectors in general are safe is that the amount of americium-241 is very small, and it is very difficult to extract it from the smoke detector. Also, the alpha particles will not travel more than an inch or so in free air, and they will be stopped by the internal design anyway, so the alpha particle field inside the smoke detector is limited to the ion chamber, also inside the smoke detector.
What is a simple explanation of alpha and beta decay?
Alpha decay:- It is a process of disintegration of an element which involves formation of a new element by loosing an alpha particle(He2+).
Example:-
84Po214 --------->82Pb210 + 2He4 + Q
Where subscripts denote atomic number, Superscripts denote atomic mass and Q is the energy released in the process.
Beta Decay:- It is also a process of disintegration but the difference from alpha decay lies in the fact that an electron is given out in the process rather than alpha particle.
Example:-
0n1 ----->1p1 + -1e0 + anti-neutrino.
Where n is neutron, p is proton, e is electron, subscripts are atomic charge and and superscripts are atomic mass.
Does nuclear radiation go away?
No, it doesn't.
Wrong, it does. There are 2 types of nuclear radiation: prompt & decay.
- Prompt nuclear radiation occurs for a period of time while the reaction that generates it is happening. Examples are the flash of neutrons, light, x-rays, etc. when a nuclear bomb explodes as well as the sustained neutron flux as a nuclear reactor is in operation. When the reaction stops, prompt nuclear radiation goes away.
- Decay nuclear radiation occurs as radioactive isotopes decay to different isotopes. As the decay happens (which is a probabilistic process) the radioactive isotope is consumed. This follows an exponential function with one half of the current amount of the radioactive isotope consumed in each period of time called a halflife. While there will always be a tiny residue of the original radioactive isotope, for practical purposes it is considered to be negligible after 5 halflives have passed. When 5 halflives of the radioactive isotope decaying have passed, decay nuclear radiation is considered to have gone away for practical purposes.
Why did the neutrino take so long to discover?
Lack of lab equipment, Cowan Reines proved the existence of the neutrino in 1956 but to do that they needed a nuclear reactor as a source of a neutrino flux
How long is Rubidium's half life?
Most rubidium (about 72.2%) is of the isotope 85Rb, which is stable. The remainder of natural rubidium (about 27.8%) is of isotope 87Rb, which has a half life of 4.88 x 1010 years and decays into 87Sr. There are a number of other isotopes of Rubidium, all of which are synthetic, having half lives ranging from less than a microsecond to something more than 86 days.
point particles that are bosons, they have no internal structure.
Where did positrons come from?
Where did they come from? They weren't invented they've always been around the positron is a fundamental part of this universe, it is the antiparticle to the electron and is found in many reactions throughout the universe.
If you mean how are they created? they can be created in many ways but a common method is a nuclear reaction called a 'Beta Positive Decay' where a Proton decays into a Neutron Positron and neutrino
P --> n + e(+) + v
How do you create a big explosion?
A sudden, rapid increase in pressure. This is most commonly done chemically, but can be done by electrical means, or mechanical pressure. If you are asking for instructions in making explosives, we do't do that here. Sorry.
