• The course covers the knowledge and application of
Medical Physics in the field of Physical Therapy.
• Medical Physics covers application of basic
concepts, laws, theories of Physics in health care and
Physiotherapy. Construction of the instruments
used in Electrotherapy.
• Understand the Basic concepts of Physics of
currents, production and physiological and chemical
• In medical physics we study the basic principal of
physics applied on modalities used in
3. Table of content
• Structure of Atom
• States of matter
• Formation of compound
• Types of elements
• Transmission of heat
• Formation of compound
• John Dalton; matter is composed of atom.
• J.J Thompson; structure of atom.
• Rutherford; discovery of Nucleus.
• Neil Bohr; electronic arrangement
• Quantum Physics; atom consist of many sub
• Atom, tiny basic building block of matter. All the
material on Earth is composed of various
combinations of atoms. An atom consists of a
cloud of electrons surrounding a small, dense
nucleus of protons and neutrons. Atoms are the
smallest particles of a chemical element that still
exhibit all the chemical properties unique to that
• Diameter of atom is 10-10 m.
• An atom consists of a cloud of electrons
surrounding a small, dense nucleus of protons
and neutrons. The nucleus contains nearly all of
the mass of the atom, but it occupies only a tiny
fraction of the space inside the atom. The
diameter of a typical nucleus is only about 1 ×
10-15 m to 1 × 10-14 m.
• Central part of an atom is nucleus.
• It has two particles proton and neutron
(nucleon). These are held together by nuclear
• It has positive charge.
12. RUTHERFORD’S MODEL
• RUTHERFORD’S MODEL
• Most of the positively charged “bullets” passed
right through the gold atoms in the sheet of gold
foil without changing course at all.
• Some of the positively charged “bullets,”
however, did bounce away from the gold sheet as
if they had hit something solid . He knew that
positive charges repel positive charges.
• Proton (p+) was discovered by E.Goldstein.
Proton has 1 unit mass. Protons have a positive
electrical charge of 1.602 x 10-19 coulomb. This
charge is equal but opposite to the negative
charge of the electron. A proton’s mass is about
1,840 times the mass of an electron. Protons
carry a positive charge of +1, exactly the opposite
electric charge as electrons. The number of
protons in the nucleus determines the total
quantity of positive charge in the atom.(atomic
• Neutron (n) was discovered by Sir James
Chadwick. The neutron is slightly heavier than a
proton and 1,838 times as heavy as the electron.
Neutron, electrically neutral elementary particle
that is part of the nucleus of the atom. The
neutron is about 10-13 cm in diameter and
weighs 1.6749 x 10-27 kg
16. Atomic mass / Atomic number
• The sum of protons and neutrons is called
• Example Carbon12.
• The number of proton in an atom is called
atomic number. Example carbon 6.
• In certain elements number of neutrons are
different in their nuclei. These are called isotopes.
• Example carbon 12, 13, 14.
• Isotope, one of two or more species of atom having
the same atomic number, hence constituting the
same element, but differing in mass number. The
nucleus, and mass number is the sum total of the
protons plus the neutrons in the nucleus, isotopes of
the same element differ from one another only in
the number of neutrons in their nuclei.
• The total number of nucleons is the same in the
atoms of this pair of elements. Atoms of
different elements with different atomic
numbers, which have the same mass number,
are known as isobars.
• The electrons are arranged in definite energy
shell or orbits around the nucleus called
principal quantum shell.
• These are seven. K,L,M,N……
• Octets rule. 2n2.
• Each shell is divided into 4 sub shells, s,p,d,f.
• The electrons fill lowest shell first.
• Electrons (e-) were discovered by sir. J.J.
Thomson.Electrons are tiny, negatively charged
particles around the nucleus of an atom. Each
electron carries a single fundamental unit of
negative electric charge–1.602 x 10-19 coulomb
and has a mass of 9.109 x 10-31 kg. The electron
is one of the lightest particles with a known
• These are responsible for physical and chemical
activities of an atom.
• A strong force of attraction is present between
electron and nucleus.
• It obeys the inverse square law.
• F 1/d2
25. Bound electrons Valance electrons
• Electrons which are close to
the nucleus are tightly bound.
These are called bound
• As the number of orbit
increases, the force of
attraction between electrons
and nucleus is weak. As a
result these are free electrons.
Positive ion cation Negative ion anion
• If an atom loses on electron it
becomes positive ion.
• Example sodium ion
• If an atom gains on electron it
becomes negative ion.
• Example chlorine ion
• Every thing that have weight and occupy space is
• Cohesive forces are attractive forces between the
molecules of matter.
• Kinetic forces are movement of the
• Matter which have fix shape and fix volume.
• Cohesive forces are strongest.
• Kinetic forces are weak. Just about there mean
• Strong m.p and b.p.
• Example wood. Iron. Glass.etc
• Matter having fix volume but not fix shape. They
take the shape of container.
• Cohesive forces weak
• Kinetic forces are strong.
• Moderate m.p and b.p.
• Example water mercury.
• Matter which do not have fix shape and fix
• Cohesive forces weakest.
• Kinetic forces are strongest.(randomly)
• Example different gases oxygen nitrogen etc
• It is considered as forth state of matter.
• It consist of atoms, Ions, free electron, etc.
• It is in the form of semi solid.
• Universe is made up of plasma.
• Elements which allow passage of heat and
electricity are called conductors.
• These elements have free electrons in their outer
most shell. These electrons allow flow of heat.
• All metals are good conductor. Cupper, gold,
• elements which do not allow passage of heat and
electricity are called insulators.
• These elements do not have free electrons in
their outer most shell. Outer shells are
• All non metals are insulators. Wood, carbon,
38. Conductivity of Selected Materials
Conductors Fair Conductors Insulators
Copper Water with dissolved
Aluminum Moist Air Wood
Iron Human Body Plastic
Mercury Carbon Pure Water
Other metals Soil Metal oxides such as
• It is a form of energy that is transferred from
one body to the other body as a result of
42. Transmission of heat
• Heat has ability to transfer from area of higher
temperature to area of lower temperature. It is
• Transmission of heat in solids is called
• If one end of a metal rod is heated, it causes
increase in temperature at that end. Kinetic
forces of molecules increase. It conduct the heat
to the other end.
• Transmission of heat in liquids
and gases is called convection.
• When fluid in a pot is heated,
kinetic energy increases,
molecules moves away from
each other, area become less
dense, the more fluid come to
take its place. The whole
process continues until the
temperature of liquid become
• Transmission of heat between air and vacuum is
• Transmission of heat from sun to earth is by
• Heat in vacuum is transmitted by
• As a substance is heated, it cause electron to
move the higher energy shell. When the electron
moves back to lower energy shell. Energy is
released in the form of heat.
Ionic compound Covalent compound
• These compounds are formed
by the complete transfer of
• Example NaCl
• These compounds are formed
by the mutual sharing of
• Example CH4