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8/12/2019 Structure of Matter & Electromagnetism
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WELCOME
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BASIC OF RADIATION
ATOM ELECTROMAGNETISM
Capt.Ridwana HabibGrading trainee(1stterm)CMH, Dhaka
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STRUCTURE OF MATTER
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MatterIndefinite composition
SubstancesEach has definite composition
Elements CompoundsCannot be decomposed to simpler substances by ordinary mean can be decomposed chemically
Atom MoleculesSmallest units smallest units
SUBDIVISION OF MATTER
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Anything which occupies space and has inertia
MATTER
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Smallest subdivision of a substance having the characteristics properties ofthat substance
MOLECULE
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Smallest particle of an element that has the characteristic properties of that element
ATOM
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SUBSTANCE
A substance is any matter that has a definite, constant composition, such aspure salt
ELEMENT
The simple substances are called element that cannot be decomposed tosimpler substances by ordinary means
COMPOUNDS
The complex substances are called compounds, formed by the chemical unionof two or more elements in definite proportions
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DIATOM
The commonly occurring gases such as oxygen (O2), nitrogen(N2), and
hydrogen(H2) occur in nature in the form of molecules consisting two atoms andhence they are called diatomNEUCLEUS
Stable Particles : Proton, Neutron & Neutrino
Unstable Particles: Mu mesons, Pi mesons , K mesons , Hyperons , Antiproton etc.
PROTONS
Elementary positive particles with mass about 1.67 10 -24g , and diameter about10-13cm. It is about 1840 times heavier then an electron
NEUTRONS
Elementary neutral particles having virtually the same mass as the proton
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ELECTRONS
Elementary negative particles with mass about 9.1110 -28 gand diameter about 4 10 -13cm
ATOMIC NUMBER
The number of protons or positive charges in thenucleus of an atom denotes its atomic number
ATOMIC MASSThe total number of protons and neutrons in the nucleus
of an atom denotes its mass number or atomic mass number
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ISOTOPES
Can be defined as atoms that have the same number of nuclear
protons (equal to the atomic number of the element) but differentnumbers of nuclear neutrons
Example: Hydrogen (H) has 3 stable isotop
H (Protium) , H (Deuterium), H(Tritium)
HYDROGEN ISOTOPEOXYGEN ISOTOPE
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ISOBARThe atoms composed of nuclei with the same mass number(A)but
different number of proton or neutron are called ISOBAR
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ISOMERThe atoms composed of nuclei with the same atomic number (Z)
and mass number (A) but different in energy state are called
ISOMER
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ISOTONE
The atoms composed of nuclei with the same number of neutron butdifferent number of proton are called isotone
Example: I & Xe
Here mass number of I=131 & Xe=132Proton number of I=53 & Xe=54
So neutron number of I=(A-Z)=131-53=78Neutron number of Xe=132-54=78..are same
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Isotopesequal Z
Isobarsequal A
Isotonesequal N
Isomersequal all the above
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Points Atomic number
(Z)
Neutron number
(N)
Mass number
(A)
Isotope Same Different Different
Isotone Different same Different
Isobar Different Different Same
Isomer Same Same Same
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ATOMIC WEIGHT
It refers to the mass of any atom relative to the mass of carbon 12isotope taken as 12
IONIZATION
The process of converting atoms to ions is termed ionization
NUCLEAR BINDING ENERGY
It is the energy necessary to dissociate nucleus into its constituent part
It is the result of the strong attractive forces between nucleons
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An induced fission reaction. A neutronis
absorbed by a uranium-235nucleus, turning itbriefly into an excited uranium-236 nucleus,with the excitation energy provided by thekinetic energy of the neutron plus the forcesthat bind the neutron. The uranium-236, inturn, splits into fast-moving lighter elements
(fission products) and releases three freeneutrons. At the same time, one or more"prompt gamma rays" (not shown) areproduced, as well.
http://en.wikipedia.org/wiki/Neutronhttp://en.wikipedia.org/wiki/Uranium-235http://en.wikipedia.org/wiki/Gamma_rayhttp://en.wikipedia.org/wiki/Gamma_rayhttp://en.wikipedia.org/wiki/Uranium-235http://en.wikipedia.org/wiki/Uranium-235http://en.wikipedia.org/wiki/Uranium-235http://en.wikipedia.org/wiki/Neutron8/12/2019 Structure of Matter & Electromagnetism
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Nuclear fusion:NUCLEAR FUSION
Nuclear fusion is a nuclear reaction in which two light nuclei (such as H-2 & He-3)combine to form a heavier nuclei (such as helium-4). The process releases excess bindingenergy from the reaction, based upon the binding energies of the atoms involved in theprocess.
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AUGER ELECTRON
Removal of an electron from tungsten atom during electron bombardment to the targetcauses the atom to have an excess positive charge and the atom thus becomes apositive ion. In the process of returning to its normal state , the ionized atom of tungstenmay get rid of excess energy in two ways :
1. An additional electron may be expelled by the atom and carry off the excess energy.This additional electron is known as auger electron.
2. To emit radiation that has wavelength within the x ray range.
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ATOMIC MODELS
JJ Thomson discovered a negatively charged particle much smaller than any atom
,which came to be called electron .
Based on Rutherford and Bohrs work a simple model of an atom may be visualized as
a massive positively charged nucleus surrounded by electrons in orbits of different
diameters.
Nils Bohr suggested that the electrons are negatively charged particle and moves
around the nucleus in various orbits .
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The orbit of electron is fixed .
Unlike the solar system with one planet in each orbit, the atomic system allows 2
electrons in the first , up to 8 in the second , up to 18 in the 3 rd, up to 32 in the 4th, up
to 50 in the 5th
The electron orbits are designated by letters: K,L, M,N,O,P and so on
An electron in the shell closest to the nucleus is in the K shell and the electron is called
a K electron
Cont
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Cont..
The attractive force between the positively charged nucleus and the negatively charged
electron is the force that keeps the electrons in the atom . This force is called the binding
force of the electron, and is inversely proportional to the square of the distance
between the nucleus and the electron.
Therefore, a K electron has a larger binding force than other electrons.
The binding energy of the electron shells varies from one element to another.
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An electron can move to either a higher or lower energy shell if the shell is not already
filled .
Other than K shell energy shells have sub-shell of slightly different energy.
e.g. L shell has 3 sub-shell.
Diameter of atom is 100000 times larger than the diameter of its nucleus.
Cont..
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IONIC BOND
The Attraction between two ion is called Ionic bond/Chemical bond
Charged atoms are called ion
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COVALENT BOND
Covalent Bonds are the strongest chemical bonds, and are formed by the
sharing of a pair of electrons ( Outer orbital electrons)
Once formed, covalent bonds rarely break spontaneously.
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IONIZATION
The Process of converting atoms to ions is termed as ionization.
Ionization is an extremely important process .Many chemical ionization takesplace between ion and solution. Ionization of air by x-rays underlies the modernmeasurement of the exposure rate of an x-ray beam. Ionization of body tissuesindirectly through preliminary release of electrons underlies the fundamentalmode of action of x-ray & gamma rays in therapy .
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WAYS OF IONIZATION
Exposure of matter to x-ray or gamma rays
Exposure of matter to stream of electrons
Spontaneous breakdown of radioactive nuclides
Exposure of certain elements to light
Chemical ionization
Thermionic emission
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ELECTROMAGNETISM
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2 Non-ionizing radiation
2.1 Non-ionizing electromagnetic radiation
2.1.1 Visible light
2.1.2 Infrared
2.1.3 Microwave2.1.4 Radio waves
2.1.5 Very low frequency (VLF)
2.1.6 Extremely low frequency (ELF)
2.1.7 Thermal radiation (heat)
2.1.8 Black-body radiation
1 Ionizing radiation1.1 Alpha1.2 Beta
1.3 Neutron
1.4 X-ray
1.5 Gamma
http://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiationhttp://en.wikipedia.org/wiki/Radiation8/12/2019 Structure of Matter & Electromagnetism
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ELECTROMAGNETIC RADIATION
Any accelerating charge not bound to an atom (including the nucleus) will emit EM radiation.
Thus, energy is transmitted through space by EM radiation .
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WAVE CONCEPT OF EM RADIATON
EM radiation is propagated through space in the form of wave. The EM wave poses wave length (), frequency () and velocity (c).
The relation between c, & of electromagnetic radiation is expressed as:
c=
All EM wave travel at the same velocity in a given medium. So in above mentioned
equation C is constant so different EM radiation varies in their wave length.
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EM SPECTRUM
Electromegnetic spectrum includes radiation from very long radio wave toshort, penetrating gamma rays. All of them travel at a velocity C invacuum.
The wave length and the photon energy of the whole range of EMradiation is summarized in the next slide
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RADIATION WAVELENGTH PHOTON ENERGY
Radio wave, Radar wave 3105cm to 1 cm 410-10to 1.2410-4eV
Infra red radiation 0.01cm to 0.0001cm 0.0124 ev to 1.24 eV
Visible light 7000 to 4000 1.77ev to 3.1 eV
Ultraviolet light 3900 to 20 3.1 ev to 124 eV
Soft X-ray 100 to 1 124 ev to 12.4 KeV
Diagnostic X-ray 1 to 0.1 12.4 KeV to 124 KeV
Deep therapy X-ray andGamma ray
0.1 to 10-4 124 KeV to 1.24 Mev
Small betatron 0.001 12.4 MeV
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REFLECTION
REFRACTION
DIFFRACTION
POLARIZATION
WAVE CONCEPT CAN EXPLAIN :
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PARTICLE CONCEPT OF EM RADIATTION
Short EM wavs such as X rays , may react with matter as if they were particle rather
than wave.
This particles are discrete bundles of energy known as quantum or photon.
The amount of energy carried out by each quantum or photon ,depends on the
frequency of the radiation.( If the frequency [number of vibration per sec] is double
than the energy is double).
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The Mathematical Expression Of Energy Of EM Radiation Is:
E=hHere, E= Photon energy
h = Plancks constant (4.13 10-18KeV-sec)
= frequency
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The product of velocity of light (C) and Plancks constant (h) is 12.4 when the unit of energy is
KeV and the wave length is in the relation between energy and wavelength is :
c= v
so, v=c/
E= hc/ =12.4/
Here, E = Energy in Kev= Wavelength in
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SI BASE:
SI UNIT NAME SI SYMBOL
METER LENGTH m
KILOGRAM MASS Kg
SECOND TIME S
AMPERE ELECTRIC CURRENT A
KELVIN TEMPERATURE K
MOLE AMOUNT OF SUBSTANCE mol
CANDELA LUMINOUS INTENSITY Cd
RADIAN Rad
STERADIAN sr
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SI DRERIVED UNITS WITH SPECIAL NAMES
QUANTITY SI UNIT NAME SI SYMBOL EXPRESSED INSI BASE UNIT
MOREFAMILIAR UNIT
Frequency Hertz Hz 1/s
Force Newton N m-kg/s2
Energy Joule J m2kg/s2 erg
power Watt W A-Sm2kg/s2
Charge Coulomb C A-S
Radioactivity Becquerel Bq 1/S curie
Absorbed dose Gray Gy m2/s2, A-S/KG rad, roentgen
Electric potential Volt V m2-KG/S3-A
Capacitance Farad F A2S4/m2kg
Magnetic flux Weber Wb m2Kg/s2-A
Magnetic fluxdensity(magnetic
induction)
tesla T Kg/s2-A gauss
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THANK YOU