Nuc.
Assignment
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Page limit 2 pages – in A4 size, Single-spacing
Topics will be distributed later.
Individual reports and no copy-paste.
Submit in soft-copy – no need to print.
Submission date: 25 May, 2013
Use LaTex – Use template of http://ijcvsp.com
Must provide referencing.
- Example of an academic paper or write-up
- If you have any choice of topic – let me know
1.1 Atomic Mass Unit [AMU]
• The unified atomic mass unit (also known as
amu, symbol: u) or dalton (symbol: Da) is the
standard unit that is used for indicating mass on
an atomic or molecular scale (atomic mass).
• It is defined as one twelfth [1/12] of the rest
mass of an unbound neutral atom of carbon-12 in
its nuclear and electronic ground state [C-12
atom has six protons and six neutrons in its
nucleus.]
• That's about the mass of one proton or neutron.
• … differentiate between, various isotopes of elements.
E.g.,
 uranium-235 (U-235) has an AMU of approximately
235,
while uranium-238 (U-238) is slightly more massive.
The difference results from the fact that U-238, the most
abundant naturally occurring isotope of uranium, has
three more neutrons than U-235, an isotope that has
been used in nuclear reactors and atomic bombs.
Neutron, Proton
1.2 Stable Nucleus
• The nucleus is the very dense region consisting of
protons and neutrons at the center of an atom.
• It was discovered in 1911, as a result of Ernest
Rutherford's interpretation of the famous 1909
Rutherford experiment performed by Hans
Geiger and Ernest Marsden, under the direction
of Rutherford.
• The branch of physics concerned with studying
and understanding the atomic nucleus, including
its composition and the forces which bind it
together, is called nuclear physics.
Rd. - Makeup
• The nucleus of an atom consists of protons
and neutrons  bound by the nuclear force
(also known as the residual strong force).
• These p/n are further composed of subatomic
fundamental particles known as quarks bound
by the strong interaction.
Rd.
• Protons and neutrons are fermions, with different values of
the isospin quantum number
• So two protons and two neutrons can share the same space
wave function since they are not identical quantum entities.
• They sometimes are viewed as two different quantum states
of the same particle, the nucleon.
• Two fermions, such as
 two protons, or
 two neutrons, or
 a proton + neutron (the deuteron)
can exhibit bosonic behavior when they become loosely bound
in pairs.
Rd.
• Fermions  any particle characterized by
Fermi–Dirac statistics and following the Pauli
exclusion principle; fermions include all quarks
and leptons, as well as any composite particle
made of an odd number of these, such as all
baryons and many atoms and nuclei.
• Bosons  which obey Bose–Einstein statistics.
1.3 Binding energy
Play from –
http://www.ndted.org/EducationResources/HighSchool/Radiography/s
tableunstableatoms.htm
1. E is close to P: mix
2. E is close to E – depart
3. 2 Electrons – both neg charge – so their lines of force
are repelled
4. 2 Ps – both positives – repelled
5. E and P  their lines of force bend towards each
other
• A force called the strong force opposes and
overcomes the force of repulsion between the
protons and holds the nucleus together.
• The energy associated with the strong force is
called the binding energy.
• The electrons are kept in orbit around the
nucleus because there is an electromagnetic field
of attraction between the positive charge of the
protons and the negative charge of the electrons.