Nuclear binding force

Nuclear energy (associated with the nuclear binding forces)... 

The ultimate structures or components of reality (top) are subatomic particles, when I was a high school student, only a few such particles were known and many scientists thought that electrons, protons, and neutrons were the basics whose arrangement in patterns accounted for the way the world was. Now literally hundreds of subatomic particles have been "discovered." The word is enclosed in quotation marks because, of course, no one has actually ever seen a subatomic particle. They are assumed to exist because their presence enables sensible interpretation of various kinds of instrumental readings. Thus modern physicists picture the universe as composed of hundreds of subatomic particles being influenced by three basic types of forces (1) the nuclear binding forces, which operate only at the extremely tiny distances inside atomic nuclei i i - uis pi... 

Figure 19.16 A plot of energy versus the separation distance for two iH nuclei. The nuclei must have sufficient velocities to get over the electrostatic repulsion hill and get close enough forthe nuclear binding forces to become effective, thus fusing the particles into a new nucleus and releasing large quantities of energy. The binding force is at least 100 times the electrostatic repulsion.

In the previous section we saw that the stability of a nucleus is affected by its neutron/proton ratio. Even among those nuclei that we consider stable, however, there is a variation in the forces which hold the nucleus together. In order to study this variation in nuclear binding energy, let us consider the process of building a nucleus from protons and neutrons. For an example, let us look at the hypothetical reaction... 

As described in Chapter 2, nuclei with more than one nucleon are held together by the strong nuclear force. Energy must be provided to overcome this force and remove a nucleon from a nucleus. This energy is called the nuclear binding energy. 

The difference in mass is significant. It would show up on any reasonably precise balance. Thus, the mass of the nucleus of carbon-12 is significantly less than the mass of its component nucleons. The difference in mass between a nucleus and its nucleons is known as the mass defect. What causes this mass defect It is caused by the nuclear binding energy the energy associated with the strong force that holds a nucleus together. 

Four parameters are thus imaged in MRI by means of mathematical calculations (I.) proton density, (2.) relaxation time Tj (= binding force between the nuclear spin grate and the surrounding molecular grate), (3.) relaxation time T2 (= binding effect between the various nuclear spins), and (4.) flow velocity. 

A mass deficiency represents the amount of matter that would be converted into energy and released if the nucleus were formed from initially separate protons and neutrons. This energy is the nuclear binding energy, BE. It provides the powerful short-range force that holds the nuclear particles (protons and neutrons) together in a very small volume. 

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