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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
What particles have very weak penetrating power?
Alpha particles have very weak penetrating power. They are heavy and charged, so they interact strongly with matter, causing ionization and losing energy quickly. Therefore, alpha particles can generally only travel a few centimeters in air and can be easily stopped by a sheet of paper or skin.
Why does gamma radiation NOT change the type of atom?
The type of atom is only changed if the proton number changes. Change in neutrons create an isotope, change in electrons create an ion and the change in protons change the atom (Hydrogen to Helium for example). Gamma radiation is the emission of a photon, of pure energy, it is neither positive or negative and it has nothing to do with the protons.
electromagnetic fields. These fields are generated by powerful magnets which create a strong magnetic field. The particles are then guided in circular paths, and as they pass through the electromagnetic field pulses, they gain energy and accelerate. This process is repeated multiple times to achieve the desired energy for the particles.
Why is density of water more in deep water?
The density of water increases with depth due to the increase in pressure. As water molecules are packed closer together under high pressure, the density of water increases. Therefore, in deep water where the pressure is higher, the density of water is also higher.
Can you board a plane with a geiger counter?
You would have to contact the airline and explain why you wish to carry a Geiger counter with you. With current security and paranoia, they will probably only let you on board if you are a researcher and have a formal letter of request from your university or institute. There's no safety reason why they wouldn't allow it during the flight.
However, the last thing the airline want is someone scaring fellow passengers by telling them they are getting irradiated by cosmic radiation whilst they fly, without being educated enough to explain how minor the effects of this radiation really are...
For example, the annual dose (from cosmic radiation) for staff working on commercial aircraft is around 200mrem (2mSv). The annual dose for someone at ground level (from radioactive rock, cosmic radiation etc) is ~300mrem (3mSv). Add to this that people at ground level, in cities are probably breathing in carcinogenic fumes from cars, factories and smoking/passive smoking, it is probably more healthy to be in an aircraft! :)
What makes up an alpha particle and how powerful is it?
An alpha particle consists of two protons and two neutrons, which is essentially the nucleus of a helium atom. It is relatively powerful due to its high kinetic energy and its large mass compared to other types of radiation. It can penetrate only a few centimeters in air and is stopped by a piece of paper or a few centimeters of human skin. However, it can cause significant damage if it enters the body through inhalation or ingestion.
What is uniformly accelerated motion?
It means that acceleration is constant.
This meaning that velocity is varying with respect to time, we see this by this formula (v - v(initial) ) / t (Time).
What is an example for a force causing an object to start moving?
The force you apply to the mouse button to make it click is.
A reduction in the strength of a signal, the flow of current, flux, or other energy in an electronic system.
How do you use electromagnets in medicine?
MRI (Magnetic Resonance Imaging) is widely used in modern medicine to image the body's internal structures in high contrast.
One new and still very experimental use is Transcranial Magnetic Stimulation: the stimulation of specific areas of the brain through electromagnetic induction. Repeated sessions have shown improvement in disorders such as depression and Parkinson's Disease. Altered states of consciousness, out of body states and religious experiences have been reported by human subjects.
How is gamma radiation used in medicine?
gamma radiation is used in cancer treatment. the most common source of gamma radiation is.
How dangerous is the threat of Water contamination from Nuclear waste?
If you put nuclear waste in a situation where groundwater can flow over it on the way to a water course, you will obviously get contamination. Nuclear waste stores have to be very carefully considered to find locations that are safe from water access.
Has the Higgs boson been found yet?
We are not sure if the theorized Higgs boson is real or not. If it is, it would be provide some support to ideas about what mass (and, therefore, gravity, which is associated mass) really is. We're still looking for experimental support that the Higgs boson is real, and now that the Large Hadron Collider is up and running, all (interested) eyes are on CERN and awaiting results.
How is nuclear power dangerous?
Nuclear energy as it is used to generate power can be dangerous. The nuclear reactors used to heat water to generate steam to spin turbines to generate electricity must be operated by individuals who know what they are doing. If something goes wrong, the duty crew must make all the right decisions and make them first time, every time. Failure to do so can cause structural elements of the core to fail and release both nuclear fuel and waste into the coolant passages in the core. (The fuel rods are designed to hold everything inside throughout the life of the fuel bundle.) This is what happened at Three Mile Island. Both mechanical failure and the failure of the duty crew to react correctly caused a meltdown. Spent fuel presents its own special problems. Fuel bundles must be recovered from the reactor and taken away and stored for an extremely long period of time before radiation levels are low enough to try to do anything with them. Fission byproducts are highly radioactive, and remain so for tens of thousands of years. Links are provided for further reading.
Is there a positron in the nucleus of an atom?
Positrons can be produced in atomic nuclei by some kinds of radioactive decay, and they can be observed to be leaving a nuclear reaction called beta plus decay. But the positron leaves the nucleus of an atom as soon as it is created. It does not (cannot) exist in the nucleus of an atom.
Do electrons have the mass as protons?
Protons are part of the nucleus, so they have less mass than the nucleus (except in the specific case of hydrogen, where the nucleus is a single proton so they have the same mass).
Electrons are much less massive than protons. It would take 1836 electrons to equal the mass of one proton.
Neutrons are very slightly more massive than protons, by just about the mass of an electron. They're close enough that they're generally treated as having essentially the same mass.
What are the major branches of physical science?
In general, the Physical sciences study non-living matter, energy, and their interactions. Earth science, Chemistry, Mathematics, and Physics are, traditionally, the main branches of the physical sciences.
There are many sub-branches. To name only a few:
Aerodynamics: Motion of air and its interaction with moving objects;
Astronomy: Motion and character of the universe and the bodies within it;
Astrophysics: Properties, origin, and evolution of celestial bodies;
Biochemistry: Chemistry of living organisms;
Classical mechanics: Behavior of objects in a system of forces;
Computer sciences: Fundamentals of Information Management and computation;
Earth sciences: Encompassing term for the study of the planet, Earth;
Electricity: Fundamentals of electrical energy, its transport, and uses;
Electronics: Emission, behavior, and effects of electrons;
Engineering (most): Development of technology from new discoveries;
Geography: Earth's features and the distribution of life over it;
Geology: Earth's Origin, History, and structure
Mechanics: Motion and behavior of objects under force;
Fluid Dynamics: Motion and behavior of fluids and gases under force;
Optics: Behavior and properties of light;
Physical Chemistry: Application of any of several physical sciences to chemical systems;
Quantum mechanics: Structure and behavior of atoms and sub-atomic systems;
Statistical mechanics: Predicts behavior of materials from atomic & molecular observations;
Thermodynamics: Transformational relationships between heat and other energy forms.
etc.
Which causes primarily by the gravitational force between earth and moon?
There is insufficient information in the question to answer it. You did not provide the list of "these". However, it seems obvious that the answer is the tides of the oceans are caused by the gravitational force between the Earth and the Moon, with the Sun also a significant part. Also, it is known that the Moon tends to keep the alignment of the Earth's axis with respect to the plane of the ecliptic relatively constant, stabilizing our seasons.
Example 1If a 235U atom splits up into two nuclides with mass number 117 and 118, estimate the energy released in the process.
SolutionA search of stable nuclides with mass numbers 117 and 118 are 117Sn50, and 118Sn50, their masses being 116.902956 and 117.901609 amu respectively. The mass of 235U is 235.043924 amu. The difference in mass 235.043924 - (116.902956 + 117.901609)
= 0.2394 amu (931.5 MeV) / (1 amu)
= 223 MeV.
Discussion
Actually, the fission is induced by neutrons, and usually the split is uneven. In reality, two neutrons are also released, but they were ignored in this example to make the estimate simple. Furthermore, the fission products are beta emitters as illustrated by example 2.
Example 2Assume the neutron induced fission reaction to be, 235U + n ® 142Cs55 + 90Rb35 + 4 n.
explain the results and estimate the energy released.
Solution
The neutron-rich fission products are beta emitters:142Cs55 ( , b) 142Ba56 ( , b) 142La57 ( , b) 142Ce58 ( , b) 142Pr59 ( , b) 142Nd60 (stable)
90Rb37 ( , b) 90Sr38 ( , b) 90Y39 ( , b) 90Zr40 (stable)
The masses of n, 142Nd60 and 90Zr40 are 1.008665, 141.907719 and 89.904703 amu respectively. The energy per fission and the decay energy are estimated as follows. Energy = 235.04924 - (89.904703 + 141.907719 + 3 x 1.008665)
= 0.210823 amu (931.5 MeV / amu)
= 196 MeV (1.6022e-13 J / MeV)
= 3.15e-11 J
Can an optical fiber transmit microwaves?
To be perfectly technical, the answer to this question would have to be 'yes', but
only because light and radio are the same physical phenomenon.
The optical fiber only conducts the electromagnetic waves that we usually describe as "light".
The waves that we normally describe as "radio" cannot pass through optical fiber.
How do neutrinos differ from photon?
A photon is a unit of light and has a mass of 0 where is a Neutrino has a small but nonzero mass. Neutrino's are similar to electrons in most regards, except neutrino's have no charge. Where photon's travel at the speed of light neutrino's come close but do not.
What are quarks and electrons made up of?
There is no evidence of a smaller particle than the quarks and electrons and other fundamental particles, but there is a theory of smaller particles called "rishons". The theory states that there are T, V, t, and v rishons. The T and t rishons are antoparticles, the T's having an electric charge of +1/3, and the t's having -1/3. The v and V are antiparticles, but they are both neutral. (Again, this is only theory.)
What happens when an unstable nucleus decays via alpha radiation?
- mass number decreases by 4
- atomic number decreases by 2
- the nuclei recoil quite strongly (compared to other modes of decay) due to the large mass of the alpha particle
Does nuclear fusion produce more radioactive waste than nuclear fision?
The waste from coal power stations has virtually no radioactive waste where as a
nuclear plants waste is nearly all toxic.
Completely Wrong. All coal waste is toxic. Coal fired power plants chuck out all the radioactive elements that were in the coal that was burned. This is fairly old news from the 70's. Excellent source: http://www.ornl.gov/info/ornlreview/rev26-34/text/colmain.html .
More facts that are totally ignored by the media as governors and industrial groups lobby to continue to launch toxic, hazardous and poisonous elements and compounds into the air from the stacks, and onto the land downwind.
The following is quoted. There is no copyright on this article at this website. Thanks to ORNL.
Web site provided by Oak Ridge National Laboratory's Communications and External Relations
ORNL is a multi-program research and development facility managed by UT-Battelle for the US Department of Energy
"Because existing coal-fired power plants vary in size and electrical output, to calculate the annual coal consumption of these facilities, assume that the typical plant has an electrical output of 1000 megawatts. Existing coal-fired plants of this capacity annually burn about 4 million tons of coal each year. Further, considering that in 1982 about 616 million short tons (2000 pounds per ton) of coal was burned in the United States (from 833 million short tons mined, or 74%), the number of typical coal-fired plants necessary to consume this quantity of coal is 154.
Using these data, the releases of radioactive materials per typical plant can be calculated for any year. For the year 1982, assuming coal contains uranium and thorium concentrations of 1.3 ppm and 3.2 ppm, respectively, each typical plant released 5.2 tons of uranium (containing 74 pounds of uranium-235) and 12.8 tons of thorium that year. Total U.S. releases in 1982 (from 154 typical plants) amounted to 801 tons of uranium (containing 11,371 pounds of uranium-235) and 1971 tons of thorium. These figures account for only 74% of releases from combustion of coal from all sources.
Releases in 1982 from worldwide combustion of 2800 million tons of coal totaled 3640 tons of uranium (containing 51,700 pounds of uranium-235) and 8960 tons of thorium.
Based on the predicted combustion of 2516 million tons of coal in the United States and 12,580 million tons worldwide during the year 2040, cumulative releases for the 100 years of coal combustion following 1937 are predicted to be:
U.S. release (from combustion of 111,716 million tons):
Uranium: 145,230 tons (containing 1031 tons of uranium-235)
Thorium: 357,491 tons
Worldwide release (from combustion of 637,409 million tons):
Uranium: 828,632 tons (containing 5883 tons of uranium-235)
Thorium: 2,039,709 tons
Radioactivity from Coal Combustion
The main sources of radiation released from coal combustion include not only uranium and thorium but also daughter products produced by the decay of these isotopes, such as radium, radon, polonium, bismuth, and lead. Although not a decay product, naturally occurring radioactive potassium-40 is also a significant contributor.
According to the National Council on Radiation Protection and Measurements (NCRP), the average radioactivity per short ton of coal is 17,100 millicuries/4,000,000 tons, or 0.00427 millicuries/ton. This figure can be used to calculate the average expected radioactivity release from coal combustion. For 1982 the total release of radioactivity from 154 typical coal plants in the United States was, therefore, 2,630,230 millicuries.
Thus, by combining U.S. coal combustion from 1937 (440 million tons) through 1987 (661 million tons) with an estimated total in the year 2040 (2516 million tons), the total expected U.S. radioactivity release to the environment by 2040 can be determined. That total comes from the expected combustion of 111,716 million tons of coal with the release of 477,027,320 millicuries in the United States. Global releases of radioactivity from the predicted combustion of 637,409 million tons of coal would be 2,721,736,430 millicuries.
For comparison, according to NCRP Reports No. 92 and No. 95, population exposure from operation of 1000-MWe nuclear and coal-fired power plants amounts to 490 person-rem/year for coal plants and 4.8 person-rem/year for nuclear plants. Thus, the population effective dose equivalent from coal plants is 100 times that from nuclear plants. For the complete nuclear fuel cycle, from mining to reactor operation to waste disposal, the radiation dose is cited as 136 person-rem/year; the equivalent dose for coal use, from mining to power plant operation to waste disposal, is not listed in this report and is probably unknown.
...
Although trace quantities of radioactive heavy metals are not nearly as likely to produce adverse health effects as the vast array of chemical by-products from coal combustion, the accumulated quantities of these isotopes over 150 or 250 years could pose a significant future ecological burden and potentially produce adverse health effects, especially if they are locally accumulated. Because coal is predicted to be the primary energy source for electric power production in the foreseeable future, the potential impact of long-term accumulation of by-products in the biosphere should be considered. "
Personally, more concerned about the complete waste slate, but the radioactive portion always deserves mention.
Simple search by high school chemistry students found the West Virginia coal trace elements shown in an average ppm for nearly 800 samples.
Antimony (Sb)
1.02
Arsenic (As)
17.13
Barium (Ba)
109.86
Beryllium (Be)
2.57
Bismuth (Bi)
0.32
Boron (B)
20.01
Bromine (Br)
23.88
Cadmium (Cd)
0.096
Cerium (Ce)
16.88
Cesium (Cs)
1.15
Chlorine (Cl)
959
Chromium (Cr)
17.85
Cobalt (Co)
7.41
Copper (Cu)
20.4
Dysprosium (Dy)
2.03
Erbium (Er)
1.09
Europium (Eu)
0.33
Fluorine (F)
62.68
Gadolinium (Gd)
1.46
Gallium (Ga)
6.45
Germanium (Ge)
3.09
Gold (Au)
6.062
Hafnium (Hf)
0.72
Holmium (Ho)
0.52
Indium (In)
0.91
Iridium (Ir)
0.95
Lanthanum (La)
9.23
Lead (Pb)
8.19
Lithium (Li)
19.09
Lutetium (Lu)
0.133
Manganese (Mn)
21.29
Mercury (Hg)
0.19
Molybdenum (Mo)
2.37
Neodymium (Nd)
8.65
Nickel (Ni)
13.99
Niobium (Nb)
3.21
Praseodymium (Pr)
3.11
Rhenium (Re)
0.57
Rubidium (Rb)
23.62
Samarium (Sm)
1.52
Scandium (Sc)
3.71
Selenium (Se)
4.2
Silver (Ag)
0.058
Strontium (Sr)
91.68
Tantalum (Ta)
0.195
Tellurium (Te)
0.083
Terbium (Tb)
0.261
Thallium (Tl)
1.194
Thorium (Th)
3.02
Thulium (Tm)
0.283
Tin (Sn)
2.2
Tungsten (W)
0.79
Uranium (U)
1.59
Vanadium (V)
24.36
Ytterbium (Yb)
0.8
Yttrium (Y)
7.53
Zinc (Zn)
14.97
Zirconium (Zr)
24.32
To determine emissions of these elements just follow the example above with the Thorium and Uranium and factor from those tons.
