Nuclear Physics

Uranium-238 and Uranium-235 do not release neutrons spontaneously in nature in the same way they do during a fission process. Neutrons are typically required to initiate the fission process in nuclear reactions. In natural settings, radioactive decay processes such as alpha and beta decay occur in uranium isotopes, but not neutron release.

Alpha particles have little ability to penetrate. They are generally stopped by a few inches of air, or a piece of paper. In general, if they strike a person's body, they are stopped by the outermost layer of skin, which is mostly made up of dead cells. If they are emitted inside a person's body, however, the first cells they hit are likely to be living. So the protection from alpha particles consists primarily of being careful not to ingest or breath anything that can give them off.

The commonest source of alpha particles that cause problems is radon gas, which is often a problem in the basements of buildings, rooms with floors that contact the earth, and in well water. If there is any doubt about the presence of radon, it is wise to test the air. Many hardware stores have kits, they can be purchased online, and a variety of companies perform service. Remediation can be done on most buildings.

Some people work in environments where dust of alpha emitting materials could be breathed in or ingested. Precautions vary depending on the materials, but anyone who could conceivably be exposed should be instructed as to safety.

Yes, that's correct. The half-life of an unstable isotope is the time it takes for half of the original sample to decay. Some isotopes decay quickly, with half-lives on the order of milliseconds, while others have extremely long half-lives, lasting billions of years. This variation in half-lives influences the stability and radioactive potential of different isotopes.

Deuterium is written

4

H

1

I'm not sure how to type superscript and subscript but the top number is the atomic weight and the bottom # is the atomic number or the amount of protons

The naturally occurring isotope of radium we encounter is radium-226. It appears in the decay chain of uranium. When radium-226 undergoes alpha decay, radon-222 is the result. The equation looks like this: 88226Ra => 24He + 86222Rn The 24He is the alpha particle, which is a helium nucleus.

Yes, a linear absorption coefficient of 0.1 mm^-1 for lead at 1 MeV gamma radiation is a reasonable value. Lead is an effective shield for gamma radiation due to its high density and atomic number, which results in strong interactions with gamma rays, leading to effective absorption at this energy level.

Physics is the broadest of the sciences. In the 1800's it was called Natural Philosophy. It is the description of "how the natural world works". Physics comprises astronomy, electronics, optics, thermodynamics, hydraulics, mechanics (statics and dynamics), atomic theory, cosmology, physical chemistry. and other fields. Some sciences like biology, organic and inorganic chemistry, botany, zoology, physiology, etc. are all physics at their base, although they are studied at a much higher level.Formerly called natural philosophy, physics is concerned with those aspects of nature which can be understood in a fundamental way in terms of elementary principles and laws. In the course of time, various specialized sciences broke away from physics to form autonomous fields of investigation. In this process physics retained its original aim of understanding the structure of the natural world and explaining natural phenomena. The most basic parts of physics are mechanics and field theory. Mechanics is concerned with the motion of particles or bodies under the action of given forces. The physics of fields is concerned with the origin, nature, and properties of gravitational, electromagnetic, nuclear, and other force fields. Taken together, mechanics and field theory constitute the most fundamental approach to an understanding of natural phenomena which science offers. The ultimate aim is to understand all natural phenomena in these terms. See also Classical field theory; Mechanics; Quantum field theory. The older, or classical, divisions of physics were based on certain general classes of natural phenomena to which the methods of physics had been found particularly applicable. The divisions are all still current, but many of them tend more and more to designate branches of applied physics or technology, and less and less inherent divisions in physics itself. The divisions or branches, of modern physics are made in accordance with particular types of structures in nature with which each branch is concerned. In every area physics is characterized not so much by its subject-matter content as by the precision and depth of understanding which it seeks. The aim of physics is the construction of a unified theoretical scheme in mathematical terms whose structure and behavior duplicates that of the whole natural world in the most comprehensive manner possible. Where other sciences are content to describe and relate phenomena in terms of restricted concepts peculiar to their own disciplines, physics always seeks to understand the same phenomena as a special manifestation of the underlying uniform structure of nature as a whole. In line with this objective, physics is characterized by accurate instrumentation, precision of measurement, and the expression of its results in mathematical terms. For the major areas of physics and for additional listings of articles in physics See also Acoustics; Atomic physics; Biophysics; Classical mechanics; Electricity; Electromagnetism; Elementary particle; Fluid mechanics; Heat; Low-temperature physics; Molecular physics; Nuclear physics; Optics; Solid-state physics; Statistical mechanics.

The Geiger-Müller region is the area on the performance curve of a Geiger-Müller (GM) tube where the voltage (or difference of potential, if you prefer) between the inner wire (the anode) and the outer case (the cathode) is sufficiently high to cause a current avalanche when any "substantial" unit of ionizing radiation (either particulate or electromagnetic) enters the detector. So much of the gas in the tube is ionized, and so many of the ions have moved in a given ionizing event that increasing the voltage won't affect any increase in this so-called avalanche current. Even increases of differential voltage in the range of hundreds of volts won't substantially alter the performance of the tube. This region, the one where current avalanches and no increase in current can be had by further increasing the voltage, is the Geiger-Müller region. This unit of ionizing radiation will ionize enough of the gas inside the tube that when the ions of gas move toward the electrodes (positive toward the negative and negative toward the positive), they will ionize more gas in the tube until much or most of the gas is ionized and moving. This will create a big "pulse" or a "current shot" or an avalanche of current that can be detected by support circuits in the electronics package that supports the GM tube. Additionally, the large-scale involvement of much of the gas in its ionized form to support this current flow will eventually insulate the anode with a big positive charge. The effect will be to "cut off" the tube and force it to "reset" or "un-ionize" throughout. This will restore conditions so that another pulse will again cause the same chain of events resulting in a "click" on counter. The electronics package records a "pulse" or a "count" of ionizing radiation, as it was designed to do. Links can be found below.

The smallest part or fragment of an atom is the Electon.

Oralloy is an acronym for "Oak Ridge Alloy". Which is an alloy of Uranium 235 and Uranium 238. The U235 is the fissile isotope that is used in fission type nuclear weapons. The actual concentration is classified, but generally U235 is greater than 90%.

It does if you want to detect the beta radiation. Beta radiation, beta particles, can be stopped with a sheet of aluminum foil. An aluminum "absorber" would act as a shield to the Geiger-Müller (GM) detector and stop the beta radiation, which is really high energy electrons or possibly positrons. Placing a shield between the source of the beta radiation and the GM detector would block the radiation, thus shielding the detector from it. The detector would be "blind" to the radiation. Note that this would be effective if all you wanted to do was look at gamma rays. The gamma rays and the beta radiation would leave the source and head to the GM detector, the beta particles would be blocked by the aluminum, and only the gamma rays would make it to the GM tube to be counted. Links can be found below.

yes

This has quite a few meanings, the most common is the starting velocity of an object. u is also somtimes used for kinetic energy

U, written majuscule, is the symbol of the potential energy in U.S.

the miniscule u can be the symbol of atomic mass unit,

e.g 1 atomic mass unit (u) = 1.66053886 × 10-27 kilograms

The element that is used to fight tooth decay in toothpaste is fluoride. There are debates as to how safe and effective this element is when added to toothpaste or water.

White is not a colour. It is sensed only by human eye. Actually white is a composite of many colours. Such a composite white light could be spilit up by using a triangular prism. This splitting of composite white light into its constituent colours is called dispersion.

The weak force is transmitted by the exchange of W and Z bosons between particles. These bosons are responsible for mediating interactions that involve the weak force, such as beta decay and neutrino interactions.

The alpha particle is the nucleus of a helium atom and hence has 2 protons and 2 neutrons. The neutron is neutral and the proton has a +1 elementary charge. The alpha particle therefore has an elementary charge of +2

A pi meson, also known as a pion, is a type of subatomic particle called a meson. Pions are the lightest mesons and come in three forms: positive, negative, and neutral. They play a role in the strong nuclear force that binds protons and neutrons together in atomic nuclei.

The nucleus of a helium-4 atom is an alpha particle. When an alpha particle, which is two protons and two neutrons, is released in nuclear decay (alpha decay), it will zip out with a lot of kinetic energy. But it will quickly slow down and pick up a pair of electrons from the environment and "become" a 24He atom.

See the following taken from wikipedia 'Nuclear free Zone' The meaning is what the local group decides, but it would certainly encompass being free of nuclear weapons. If a local authority which included a military nuclear weapons facility decided to ban it, it would introduce some farcical scenes, but this would probably not happen. Presumably the local group would not go so far as to ban medical use of radioisotopes. ''A nuclear-free zone is an area where nuclear weapons (see Nuclear-Weapon-Free Zone) and/or nuclear power is banned. The specific ramifications of these depend on the locale in question. Many local authorities worldwide have declared themselves "nuclear-free". However, this label is largely symbolic, since most local authorities would be powerless to stop the construction of a nuclear plant if one was planned for the area. In the case of New Zealand its status as a nuclear-free zone is not symbolic but enshrined in the nation's legislation. New Zealand was the first Western-allied nation to legislate towards a nuclear free zone, effectively renouncing the nuclear deterrent.''

A change in speed divided by time is called acceleration. If the acceleration is negative, it is called deceleration. Technically, acceleration is the first derivative of velocity, and velocity comprises both speed and direction. Even more technically, the limit of the delta change in speed (velocity) divided by delta time, as the delta time approaches zero, is the acceleration.

Finally, by Newton's Second Law of Motion, acceleration is force divided by mass, so it is also true that a change in speed divided by time is force divided by mass.

INFRARED RADIATION is also referred to as Heat Radiation.