Nuclear Physics

It takes 4 half-lives for something with 400 cps to decay to 25 cps. The half-life of 131I is 8.0252 days, so it would take four times that, or 32.1008 days for this to happen.

Atoms cannot trade neutrons and protons. In particle physics, it is theorized that atoms exchange certain subatomic particles all of which are much smaller than a proton or a neutron. Atoms can share electrons, in fact, that is the definition of a covalent chemical bond.

Certain atoms under the right conditions can give up or receive one or more electrons from another atom, thereby giving rise to cations and anions.

The alpha particle is a helium nucleus. Its symbol is 24He2+, meaning 2 protons, 2 neutrons, and no electrons.

The half-life is a fixed period of time: the average time it will take for one of every two atoms to decay to another isotope or element.

So no matter how much of a given radioactive isotope that you start with, only one-half of it will still be that isotope after a single half-life period. Likewise only half of that remaining material will be the same isotope after another half-life period.

Of course, some of the atoms will be decaying all the time, so the half-life is only a convenient way to define the quantity at any given time.

The Rad is a unit of ionizing radiation, measuring its energy distribution in air. A Rontgen is similar, but it measures the energy absorbed by an object. A REM is a Rontgen Equivalent Man, so it measures the energy absorbed by a human being.

No, radioactive decay is not affected by temperature, at least, not in anything like a normal range. At millions of degrees, yes, it would speed up.

The intermediate product is neptunium 237 ( a very long-lived radioisotope).

An alpha particle, consisting of two protons and two neutrons.

The range is within 10-15 Meter (diameter of medium sized nucleus)

Close, but not exactly. Hydrogen is not formed by nuclear reactions in stars, hydrogen was formed not long after the Big Bang, when the expanding universe had cooled sufficiently that an electron and a proton could combine to form a hydrogen atom. Helium and all the other elements that are heavier than hydrogen, were formed by the process of nuclear fusion, in stars.

Only a tiny fraction of a percent. Its easier to simply give the total estimate than calculate percent. However I don't have the figures in front of me now. The largest contribution is probably the Hiroshima & Nagasaki bombings with all other contributions to the total being orders of magnitude less.

Let's take a little trip through the history of science and bring things current. It was Ernest Rutherford who first split the atom in 1917 by bombarding nitrogen with alpha particles, and he and his team continue to investigate. John Cockcroft and Ernest Walton, Rutherford's students, applied a different twist in 1932, and they used a particle accelerator (the Cockcroft-Walton accelerator) to shoot protons at lithium nuclei. James Chadwick discovered the neutron at this time, and Enric Fermi and associates in Roma experimented with bombarding uranium with neutrons in 1934. And it was Ida Noddack who, in 1934, first proposed the idea of atomic or nuclear fission. From there, the number of investigators grows and the trails branch. Many of these early investigations were looked at under the science of chemistry, and physics was in the process of wrestling them away and making them its own. Use the link below to review the history of nuclear fission. It's chockablock with the names of giants in the history of the new physics.

The most penetrating power is for beta particles compared to those given here.

Nuclear fuel rods could not go through the Earth because of the intense temperature and thickness of the Earth's layers. A while back somewhere in Russia , people made a giant hole in the ground (i don't know how many miles wide it was) and sent giant super drills inside. They got 7 miles deep as far as i can remember , that barely scratched the surface of the Earth. They could not continue because the temperature was too intense and the rock was too tough to work with (diamond super drills were needed to pierce the rock but was too expensive). If we or any other country would have thought of another method it would have surely been used by now.

Well it is not a fixed ratio, each element has its own diameter for the atom and nucleus depending on atomic number and atomic weight. but an idea can be given: for a certain elemnt the atom daimeter is 225 picometer and the nucleus diameter is 6 femtometer ,the ratio would be ( 225x 10^ - 12) /(6x 10^ - 15)= 37500.

yup.

The length of time for the second half-life is the same as the first half-life. Each half-life represents the time it takes for half of the radioactive atoms in a sample to decay. This process continues exponentially with each subsequent half-life.

Photons are not solid objects, they are packets of energy, which are also describable as waves, and if the pathway of two photons intersects, they will pass through each other, although in some cases there is interference, if the waves align in the right way. Interference will cause a pattern in which there are brighter than normal bands, where the waves coincide, and darker than normal bands, where the waves are opposed. However, in the case you describe, of infrared light and visible light, there won't be any interference pattern. When the frequencies differ, there is no alignment of the waves.

mass of proton is 6 x pi raised to power 5 times mass of electron

Only 1/32 of the original radioactive material will remain.

(½)5 = 1/32

The atomic mass increase with 1 unit.

Uranium-235 and plutonium-239 release alpha, beta, and gamma rays during the process of radioactive decay. Alpha particles are helium nuclei, beta particles are high-energy electrons or positrons, and gamma rays are electromagnetic radiation.

if they give you a diagram of half life, it is very hard to find the answer. unfortunatly my test is about that adn I don't know how to do it. please help me? i'm not dissappointed yet,

Neither, a CAT scan is one where computers are used to synthesise an image, but the radiation used is usually X-rays, though positron emission can be used, in this case it will be using appropriate radiation sources. Fusion and fission don't come into it.

Alpha rot follows.