explian nuclier fussion and fisson?

Answer 1

Atomic nuclei are constiuted of protons and neutrons, also known as nucleons. The number of protons is called atomic number Z and it determines the total electric charge of the nucleus. The total number of nucleons (protons + neutrons) is called mass number A because the mass of the atom is concentrated in the nucleus (electrons are approximately 1800 times lighter than nucleons). So, the number of neutrons in a nucleus is A - Z.

There is a law of conservation of baryon number in elementary particle physics, which tells that the sum of the baryon numbers of all particles before the reaction is the same as the sum after the reaction. Baryon particles have baryon number +1, and antiparticles -1. Mesons and leptons have baryon number 0. Since the only present baryons in a nuclear reaction are the nucleons and they all have baryon number +1, this law comes down to the law of conservation of mass number A.

However, it turns out that mass is not strictly conserved in a nuclear reaction. This is beacuse of the BINDING ENERGY of nuclei. Namely, the mass of an atomic nucleus is slightly less than the sum of the masses of its constituents. This is because you need to invest a certain amount of energy to dissolve a nucleus to its elementary constituents. And, because E = m c^2, the invested energy increases the mass of the system. Conversly, binding energy is equal to:

B = [Z mp + (A - Z) mn - M] c^2

mp - mass of proton
mn - mass of neutron
M - mass of the nucleus

It is customary to work with atomic masses rather than nuclear, since it is the former that is measured experimentaly.

There is a plot showing biniding energy per nucleon B/A as a function of the mass number A of the isoton. It has a maximum at for Fe - 56. Since A is conserved before and after the reaction, we can say that energy can be produced in two ways:

1) When a heavy nucleus (such as U - 235) is split onto lighter fragments, which is nuclear fission;

2) When two light nuclei (H - 2 and H - 3) are merged to give a heavier nucleus (He - 4).

However, there is a large difference in the mechanisms that produce these reactions. Fission of a nucleus can be down by absorption of a neutron. In turn, the split nucleus releases 2 to 3 neutrons which are capable of spliting more nuclei and a chain reaction can start. If it is uncontroled, as in an A - bomb, a large amount of energy is released in a very very short time - explosion. If it is controlled, it can be a power generator - nuclear reactor. Fussion, on the other hand, relies on overcoming the Coloumb repulsion force between the positive nuclei, which can only be done if the atoms move fast relative to each other, i.e. they have high kinetic energies, which means high temperatures. The only way we can achieve suitable conditions for a fussion to go on is by exploding a small fission bomb in a hydrogen environment, which is uncontroled and is an H - bomb. Sustainable controled nuclear fussion has not been achieved so far!

Answer 2

Nuclear Fusion :
this a process which can't be carried out at normal temperatures.In this process, 2 hydrogen molecules combine together to form a helium molecule, with the release of a large amount of energy. This is the energy that the sun emits in the form of sun light. The temperature required for this process is about 10-15 million kelvin.

Nuclear Fission :
This process is just the reverse of what is performed in fusion. This can take place at room temperatures, which is employed even in the gereration of electricity thro' nuclear reactors. In this process, a neutron is supplied at a very high speed and is made to hit a Uranium-235 nucleus, hih is very unstable compared to U-238, which splits giving off a large amount of energy and an atom each of Krypton and Barium and 3 neutrons.

Answer 3

Simply in fission an atom is spared and in fussion the two or more atoms are united. Both techniques requires high amounts of energy to execute them.

Answer 4

nuclear fission breaks a nucleus into two necleiafter the bombardment
and nulear fusion joins two nuclei to make one.

its the simplest way to understand.....but if u need einsteinian answer then let me tell u ...u wont get a damn idea from the book or encyclopedia about ur answer.

Answer 5

My professor talked about it today in class however he is not American and his accent was hard to understand so I would have to go back and read it... sorry