Standard of Competence, Basic Competency, and Indicator
137 Coulombs law, it will cause electrostatic force in the form of repulsion force.
But why protons can be in fused the atomic nucleus? The gravity causes the attraction force between masses of nucleon, i.e.
proton with proton, proton with neutron, neutron with neutron. While electrostatic force causes repulsion force between proton and proton charged.
Nuclear force is greater than the grafity and electrostatic force. Nuclear force working between proton and proton, proton and neutron, or neutron and neutron.
The force that responsible for binding proton and neutron into atomic nuclei is the nuclear force. Energy that occurs is nuclear energy.
Nuclear force only works at short distances. If the nuclear force applies in a long distance as well, all particles in the universe will clump together. At the
distance more than 4 fermi 1 fermi = 10-15 meters this force should be ignored. That has been shown in Rutherford experiments.
b.
Nuclear Binding Energy
Their nuclear binding energy is evidenced in the fact that the mass of the atomic nucleus or nucleon mass is not equal to the mass elementary particle. A
number of protons and neutrons that having mass M will be through a mass reduction when that protons and neutrons form the nucleus nucleus mass M.
The energy released when a free nucleon forming nucleon bound that called the nuclear binding energy. Because the mass is equivalent to energy , the nuclear
binding energy can be searched by finding the difference between the mass of a nucleon is currently free with the mass of the nucleus.
The amount of the nuclear binding energy expressed by a margin around the nucleon mass amounts [proton mass m
p
and neutron mass m
n
] with a nucleus mass formed which can be expressed in the equation:
E
B
= [ Z . m
p
+ A-Zm
n
] - m
nucleus
x 931.5 MeV M-A= [ Z . m
p
+ A-Zm
n
] - m
nucleus
Note: EB = nuclear binding energy
m
p
= proton mass m
n
= neutron mass
138 m
nucleus
= nucleus mass Z = the number of protons in nucleus
A-Z = the number of neutron in nucleus M= relative atomic mass. The average mass of isotopes of the standard C- 12
A= the number of protons , electrons , neutrons in atomic mass
While the mass defect is denoted as: Δ MeV = M-A
M = A +
5 ,
931
The formula then inserted in nuclear binding energy equation , it becomes:
E
B
= [ Z . {A
p
+
5 ,
931
p
} + A-Z {A
n
+
5 ,
931
n
}] - A
nucleus
+
5 ,
931
nucleus
s.m.a x 931.5 MeV
It will be obtained the same results with the nuclear binding energy formula before. Then the general formula of nuclear binding energy is as
follows: E
B
= [ Z . Δ
p
+ A- Z. Δ
n
] - Δ
nucleus
MeV Binding energy per nucleon
is nuclear binding energy divided by the amount of nucleons in the nucleus. It is expressed in the equation:
Binding Energy per Nucleon =
A
B
E
Note: A = mass number
Here is an illustrative graph of nuclear binding energy with mass number: