structure of matter & electromagnetism

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/Neutron


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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/Radiation


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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

structure of matter & electromagnetism

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