Physics is a Greek work and in a wider
sense it means science of nature.
All physical phenomena
has to be reproducible
is one of the vital
elements in physics.
It is important that all the theories be
established by experiments or observations
as it is the initial step towards the
progress of any physical theory.
The next step would comprise of
structuring a model or theory
in order to explain the
experiment or the observations.
Besides producing results
of the said theory
a model also has to
make predictions.
Predictions are important to clearly
grasp the model of the physical process.
To conclude the theory
needs to be corroborated
by the experimentations
offered by the model.
The model will be accepted and validated
only if the forecasts are correct.
It is important that more
experiments be directed with
more precision to test the
theory over and over again.
In physics it is said
that an experiment might
be enough to quash a
model and there are
no fixed numbers of experiments which can
verify that a theory is absolutely correct.
There is dissimilarity among models
overall and fundamental concepts.
Models are basic descriptions of nature
whereas fundamental theories are sources
on some maxims from which in principle all
physical occurrences can be explained.
Like, a complicated system is
abridged by justified suppositions.
These models play a vital role
in nuclear physics where the
collaboration is very complex to
permit a usage by first principles.
For all situations it is important that
a theorist be imaginative and intuitive
as having a good imagination is more
significant than being knowledgeable.
It denotes the cognizance of mechanics
of how the universe functions.
History of Physics
The rudiments of what
has now become physics
were mainly derived from
fields like optics,
astronomy and mechanics,
these subjects were
meticulously unified via
the study of geometry.
All these mathematical disciplines
started in the ancient times
with the Babylonians and Greek
writers Ptolemy and Archimedes.
The ancient beliefs concentrated
on explaining the nature
through ideas such as the four
types of cause by Aristotle.
The lucid understanding of nature started
in Greece with Pre-Socratic philosophers.
Since the Archaic period which was
somewhere around 650-480 BCE.
It was Thales from Miletus
who refused to accept any
mythological, supernatural or
religious explanations for
the natural events that
happened around, instead he
said that for every event
there was a natural cause.
Thales was successful
in many progresses and
accepted water as the
basic element and
experimented with various
subjects like magnets
and rubbing amber to
form cosmologies.
Thales has been names as
the "Father of Science".
There were many after Thales like
Anaximander, Heraclitus, Leucippus who
challenged each other’s theories and it
was Democritus who finally discovered
the theory of atomism, his theory said
that all the things in the universe
were composed of indivisible and
imperishable elements known as atoms.
This was milestone in
the history of physics
and to a much evolved
atomic theory of
today, as everything revolves around the
atoms, their size, state, arrangements etc.
Aristotle had discovered physics in a much
detailed way, his writings and works and
his student led to the discovery of the
laws governing the physical phenomenon.
In India the philosopher
Maharishi Kanada was
the first to uncover the
systematic theory of
atomism in 200 BCE which
was further detailed by
two Buddhist atomists
Dignaga and Dharmakriti.
The theories of Indian philosophers were
merely based on logic and void of any
experience or experiments
and were therefore
considered as nonconcrete
and entangled.
Later in 499 BCE astronomer
Aryabhata offered the theory
of earth’s rotation through
his works Aryabhatia.
ShenKuo from China has
been accredited with the
study of magnetism and
described the magnetic
needle compass, later on
he developed the camera
obscura (device which later
led to photography).
IbnSina a famous polymath from Uzbekistan
then Bukhara made many important
contributions in the fields of optics,
philosophy, physics and medicine.
Ibn-Al-Haytham is considered as
the founders of modern optics.
Works of the Muslim scientists
like Abu RayhanBiruni and Ibn Al
Haytham travelled to Europe which
was studies by the scholars.
The awareness of
historical works entered
West by translation of
Arabic works to Latin.
This re-introduction of works
was merged with Judeo Islamic
doctrinal explanations and the
Medieval European scholars were
greatly impressed by these works
as they wanted to reunite the
philosophy of the historical
theorists with Christian theology.
Mechanics
The science which is related
with the behaviour of bodies
when force or displacement is
applied and the consequent
effects of these bodies on
the surroundings is known
as mechanics or we could
frame it in an easier way;
the science that is concerned with
the motion of physical bodies
under action of forces, inclusive
the time when a body is at rest.
This theory further leads to studies
of various topics such as electricity,
magnetism, and gravitation as per
the nature of forces connected.
Considering the fact that one can pursue
the manner of how the bodies move
when these forces are applied, this
is actually what mechanics means.
Mechanics was the first
among the few exact
sciences that was developed
in the ancient times.
The internal beauty of
mechanics as a mathematical
discipline and its
early extraordinary
accomplishment in accounting and in
computable facet for the motions the Earth,
of the Moon, and other terrestrial bodies
had huge effect on metaphysical thought and
gave motivation towards the methodical growth
of science into the twentieth century.
There are three branches which
mechanics can be divided in
Statics deals with forces acting
in and on a body which is at rest.
Kinetics that endeavours
to clarify or forecast
the motions which will
occur in a certain state.
Kinematics which defines the probable
motions of a body or structure of bodies.
On the other hand, mechanics
can be distributed
as per the type of
system studied.
The most simple of all
mechanical system is particle,
which can be described
as a very small body
which does not have any
internal structure or shape
and is of no importance
in the definite problem.
The motion of a system which has two or
more particles which apply forces on each
other and perhaps endure forces applied
by bodies in the external of the system;
this is a more complicated situation.
The principles of mechanics are functional
with three overall realms of occurrences.
The motions of universal bodies
like planets, stars and satellites
can be foretold exactly many
years before they can happen.
The theory of relativity
foretells some deviancies from
the motion as per the Newtonian
or classical mechanics.
Nevertheless these deviations are too
small to be observed without proper
techniques excluding problems which involve
a big part of the noticeable cosmos.
As the second demesne,
ordinary substances on earth
which are of microscopic
size, which move at a speed
that is lesser than light,
are explained by classical
mechanics without
important rectifications.
An engineer who structures
aircraft and bridges might use
the Newtonian laws of classical
mechanics with assurance
even if the forces seem to be
complex and the calculations
do not have the minimalism
of celestial machines.
The behaviour of electromagnetic
and matter radiation on atomic
and subatomic scale encompasses
the third realm of phenomena.
Even though there have
been many achievements
earlier against the
description of atoms where
classical mechanics is
concerned these phenomena
are appropriately used
in quantum mechanics.
Classical mechanics studies the motion
of physical bodies under the effect of
forces or with the steadiness of physical
forms when all forces are stable.
The topic may be assumed as the
expansion and use of basic
suggests first articulated in
Philosophiae Naturalis Principia
Mathematica by Isaac Newton,
also known as Principia.These
hypothesizes are known as the
Newton’s laws of motion.
It is amazing to know that even
though the three laws of Newton;
momentum, angular
momentum and conservation
of energy are not
deliberated to be essential
or precisely correct they continue to be
true in relativity and quantum mechanics.
Force in modern physics is not
an essential perception anymore
and mass is the only one among
the many traits of matter.
Angular momentum, energy and momentum
continue to be the centre of attraction.
The enduring significance
of these philosophies
congenital from conventional
mechanics might
help to elucidate why this topic preserves
such great prominence in science currently.
Geneses of Mechanics
Nicolaus Copernicus changed
the view of people
about how they thought of
universe in his book De
revolutionibusorbiumcoelestiumlibri
VI -six books
about the revolutions of
the heavenly planets.
Copernicus mentioned how the predicting
the position of planets would become
much simpler if sun instead of earth would
be taken as the centre of the cosmos.
There were certain problems with the
theory of Copernicus as he did not
explain why the motion was not apparent
if earth was spinning on its axis.
Italian scientist Galileo
Galilei provided with an
answer to this he experimented
with motion of balls
on inclined planes and
concluded that physical bodies
do not require a proximate
reason to be in motion.
As a substitute, a body moving
in the horizontal course would
incline to stay in motion
except something obstructed it.
This is why earth’s
motion is not ostensible.
Everything on earth and
surrounding it are in motion
together which is why
they seem to be in rest.
Many theorists like
Galileo, Descartes, Kepler
and other prepared the
stage for Newton’s
impressive synthesis he
additionally gave to the
world the theory of
universal force of gravity.
Newton also published his book
Principia, in which he set out
his basic hypothesises regarding
motion, mass and force.
Wave
A commotion which travels through
a medium, mass or space,
from one location to the other
can be defined as a wave.
The motions of wave
transfer energy from one
pint to the other and
this relocates the
particles of the mode of transmission and
there is very less or no mass transported.
Instead of oscillating
or vibrating, waves
"consist" around most of
the stable locations.
Waves could be distributed
in two main types:
Mechanical waves which
promulgate via a medium,
the material of the
medium is distorted.
The distortion backs itself
because of the restoring
forces which results
from its own distortion.
Like sound waves promulgate from
air molecules and crash with their
neighbours, on colliding they tend
to bounce away from each other;
restoring force and this keeps
the molecules going and
they continue travelling
in the course of the wave.
Electromagnetic waves
comprise of periodic
oscillations of magnetic and
electrical fields which
are initially produced
by particles which are
charged and hence can
travel through vacuum;
these waves do not need a medium to travel.
They have different wavelengths ad
comprise of microwave, infrared radiation,
radio waves, gamma rays, ultraviolet
radiations, visible light and X-rays.
Waves can be defined by
wave equations which
set out how the disruption
ensues over time.
The type of the waves decides the
mathematical form of the equation.
Additionally, the activities of particles
in quantum mechanics are termed as waves.
The gravitational waves also
move through space;
it is because of the movement or vibrations
caused in the gravitational fields.
A wave could either
be longitudinal or transverse.
Longitudinal waves take
place when the oscillations
are parallel to the course
of energy promulgation.
Transverse waves take place when a
disruption generates oscillations
which are perpendicular to the
promulgation of transfer of energy.
In free space all electromagnetic
waves are transverse whereas
mechanical waves could either
be longitudinal or transverse.
There is no single all-inclusive
direct definition of wave.
A vibration happens when particles
of a medium of an elastic body
move periodically back and forth
which happens when any physical
system is moved from its standing
position and permitted to
respond to the forces which try
to reinstate the equilibrium.
Nonetheless, a vibration
is not inevitably a wave.
An effort to outline the essential and
adequate physiognomies which qualify
a phenomenon to be named a wave
results in an uncertain border line.
Description of waves is associated
closely to their physical
source for every precise
occasion of a wave process.
Like the acoustics is differentiated from
optics in that sound waves are connected
to a mechanical than electromagnetic wave
transmission triggered by vibration.
Perceptions like elasticity, momentum,
inertia and mass hence become
essential in explaining acoustic, as
discrete from optic, wave processes.
This difference in origin
hosts definite wave facets
specific to the properties
of the involved medium.
For air: pressure, shockwaves or vortices.
For solids: dispersion
or Rayleigh waves etc.
Additional properties, frequently
defined in terms of derivation,
might be indiscriminate to all
waves because the theory of wave
signifies a certain branch of
physics which is connected with the
properties of wave processes
self-sufficiently of their bodily source.
For instance, established
on mechanical
origin of acoustic waves,
a moving disruption
in space-time can occur only if the medium
involved is infinitely pliable and stiff.
If all the fragments
building up a medium were
tightly bound, then they
would be vibrating as one
without any interruption
in the transmission of
the vibration and
consequently no wave motion.
Whereas, if all the fragments were
free, there would be no transmission
of vibration and once again resulting
in no wave motions at all.
The above statements would not be
valid if waves do not need a medium;
they show characteristics
which are relevant
to all waves irrespective
of their origin.
The phase of a vibration within a wave
is distinct for adjacent points in space
as the time taken to reach the adjacent
points is disparate for every vibration.
Physical Properties
There are some common behaviour which
waves exhibit in certain situations:
Transmission and media -
Waves usually move in a
straight line via
transmission medium and they
could be linear medium,
bounded medium, isotropic
medium, uniform medium
and anisotropic medium.
Absorption - Certain waves which
strike matter are absorbed
by them transforming them
into a vibrational mode.
Reflection - On striking a
reflective surface waves change
their course so that the angle
which is made by the incident
wave line normal to the surface
is equal to the angle which
is made by the wave that is
reflected and the same line.
Interference - Waves which encounter
with one another combine by
superposition and create new wave
known as interference pattern.
Diffraction - On encountering a hurdle
which bends the wave is diffraction.
Polarization - When a wave
motion happens in concurrently
two orthogonal directions
it causes polarization.
Only transverse waves can be polarized.
For example, the electromagnetic
waves transmitting
in space can be polarized
as they are transverse.
Sound waves are longitudinal
hence cannot be polarized.
Dispersion - the best example of
dispersion is when white light
passes through a prism which
produces a spectrum of colours.
Thermodynamics
This section of physics
studies the temperature
and heat and their relation
to work and energy.
Thermodynamics describes macroscopic
variables like pressure, entropy and
integral energy which partially
define radiation or a body of matter.
According to thermodynamics
the actions of those
variables depends on the
general constrictions
which are mutual for all materials, beyond
the unusual properties of specific things.
The macroscopic explanation
of processes and bodies
can be referred to as
thermodynamics in plain terms.
Default to equilibrium as
contract to non-equilibrium
is what denotes the plain
term thermodynamics.
The competent term 'statistical
thermodynamics' denotes
to explanation of processes
and bodies in terms
of the other microscopic
constitution of matter or
atomic, using probable and
numerical intellectual.
One of the vital concepts in thermodynamics
is thermodynamic equilibrium.
The most distinctive
quantity and well defined
system of thermodynamics
is its temperature.
The exact study of thermodynamics
gets more tough if the processes and
systems of curiosity are moved away
from the thermodynamics equilibrium.
Comparatively easy estimated
calculations, still, using the
variables of equilibrium thermodynamics,
are of much applied value.
Many essential applied
engineering circumstances,
as in refrigerators or
heat engines, can be
estimated as structures
containing of many
subsystems at diverse
pressures and temperatures.
If a physical procedure happens very fast,
the equilibrium thermodynamic variables,
like the temperature, will not be properly
set to supply a helpful calculation.
There are four laws in
the fundamental types
of entities in
thermodynamics, however
originally there were three laws which
have now been classified into four.
The Zeroth Law says that if there are
two bodies which are in equilibrium
with a third body, then they are also
in equilibrium with one another.
Hence temperature
is established as a
fundamental and measurable
property of matter.
According to the First Law the total
rise in the energy of a system is
equivalent to the rise in thermal energy
and the effort done on the system.
This means that heat is
a form of energy and is
thus subject to the
principle of conservation.
The Second Law states that heat energy
cannot be transmitted from a body at a
lower temperature to a body at a higher
temperature without additional energy.
Now you know why air conditioners
are expensive to run.
The Third Law states
that the entropy (waste
energy) of a crystal at
absolute zero is zero.
Entropy is at times
referred to "waste energy,"
which is the energy that
is incapable of doing any
work, and as there is no
heat energy of any kind
at absolute zero, there
can be no waste energy.
Entropy is also a degree of
the disorder in a system, and
despite the fact a perfect crystal
is by description flawlessly
ordered, any positive value of
temperature signifies there
is motion inside the crystal,
that leads to disorder.
Because of this there can be no
physical system with entropy lower
than that, hence entropy will
always have a positive value.
It is important that a physical system’s
internal atomic mechanism falls into one of
the two categories for
statistical thermodynamics
and thermodynamics
to apply on it.
The atomic mechanism should be so fast that
in the given time frame the atomic states
speedily bring system to its self-state
of internal thermodynamic equilibrium.
The atomic mechanism
is so slow that in the
given time frame the
system is left unchanged.
The fast atomic mechanism is because
of the internal energy of the system.
They are mediators for the
macroscopic alterations
which are concern for
statistical thermodynamics
and thermodynamics, as
they bring the system
close to thermodynamic
equilibrium in no time.
Statistical mechanics and
thermodynamics are not applicable if
intermediate rates are present
as this rate of atomic processes
doesn’t bring the system close
enough to thermodynamic equilibrium
within the given time of the
macroscopic process of interest.
The separation of time
gauges of atomic processes
is a theme which repeats
all through the subject.
Like the traditional thermodynamics
is categorized by its study of
resources which have or characteristic
equations or equations of state.
They prompt equilibrium
associations among temperature
and inner energy and macroscopic
mechanical variables.
They show the organized individualities
of the material of the system.
A conventional material can
normally be explained by a
function which makes pressure
reliant on temperature and
volume, the pressure which
is build is much faster than
any enforced modification
of temperature or volume.
The specifics of thermodynamics could
be elucidated by describing objects
as assemblies of atomic objects
which follow Hamiltonian dynamics.
The atomic or microscopic
objects occur in species,
and the objects of all
species being the same.
This cause of resemblance
and statistical methods
could be used to account
for the macroscopic
characteristics of
thermodynamic system as per
the characteristics of
microscopic species.
This description is known as
statistical thermodynamics and is at
times denoted by the term statistical
mechanics, although this term
could have a broader meaning,
speaking of microscopic objects like
economic quantities which do not
follow the Hamiltonian dynamics.
Electromagnetism
Electromagnetism is a part of
physics that covers magnetism
and electricity and the
interaction with each other.
It was first learnt about
in the 19th century and has
been broadly put to use in
modern world of physics.
The science of electromagnetic fields
is fundamentally electromagnetism.
A field made by objects which
are electrically charged
is known as an electromagnetic
field.Infrared waves,
radio waves, ultraviolet
waves and x-rays are all
electromagnetic fields in a
particular range of frequency.
The occurrence is also known
as electromagnetic induction.
Likewise the magnetic field is generated
by motion of electric charges.
The basic law of electromagnetism is
known as "Faraday's law of Induction."
The occurrence of electromagnetism
was learnt in the 19th century which
helped Albert Einstein in the discovery
of the special theory of relativity.
According to the theory of Albert
Einstein, with a relative motion,
magnetic and electric fields can
be turned into one another.
It was not only Albert Einstein
who discovered this phenomenon
and its uses but the works
of many amazing scientists
like James Clerk Maxwell,
Michael Faraday, Heinrich Hertz
and Oliver Heaviside who
contributed to the theory.
In the year 1802, a
scholar from Italy proved
the relationship
between magnetism and
electricity by refracting a magnetic needle
with the help of electrostatic charges.
Electromagnetism is mainly a
speculation of a mutualcountenance
of an unrevealed force, called
the electromagnetic force.
The force is visible when
an electric is traveling.
The movement caused by the
travel generates magnetism.
In 1865, James Clerk Maxwell was
the first to present this theory
to the world through his publishing’s
of electricity and magnetism.
Using Maxwell’s theory as the
foundation many other scientists
discovered the effects and
applications of magnetism.
Electromagnetism has been stretched
to the area of quantum physics as
well, where light interacts as a
particle and proliferates as a wave.
It has been evidenced that magnetism can
give rise to electricity and vice versa.
An example to prove is that
of an electric transformer.
The exchange happens within the transformer
which gives rise to electromagnetic waves.
Another datum of these waves is that they
do not require a medium to proliferate even
though their speed is
comparatively leisurelier
while moving through
transparent materials.
After the electromagnetic waves
had been discovered by James
Clerk Maxwell it was later on
established by Heinrich Hertz.
Maxwell copied a wave form of
magnetic and electric equation which
presented that the magnetic and electric
fields had the nature of waves.
The aspects which make the
electromagnetic waves different
from one another are the
frequency, polarization
and amplitude, like a laser
beam is rational and
there is only one frequency
in the radiation.
There are different kinds
of waves which differ
in frequencies like
radio waves that are at
extremely low frequencies
whereas the x-rays
and the gamma rays both
have high frequencies.
Electromagnetic waves can
proliferate to quite long
distances and are unaffected
by any hindrances;
they could be huge towers or strong walls.
The exceptional interaction of
magnetism and electricity has
helped in many developments in
modern science and technology.
There are continuous
efforts and steps being
implemented all over
the world to uncover
more properties of electromagnetism and how
they could be helpful in our everyday work.
More types of forces are gravitational
forces, weak and strong forces.
Combining the electromagnetism with a
weak force produces electroweak force.
Applications of Electromagnetism
There are many uses of electromagnetism
in the world of physics and science.
The most common application of
electromagnetism in its use in motors.
There is a switch present in
the motor which continuously
switches the polarity
of the motors outside.
The same thing is performed
by an electromagnet also.
The direction can easily be
changed by reversing the current.
There is an electromagnet present in
the interior of the motor but the
current is controlled in a way that
the exterior magnet repels it.
The CAT scan machine is a well -known
application for electromagnetism.
The machine is used in
hospitals to identify disease.
Our body has current within
and the stronger the
current is the stronger
the magnetic field.
With this technology the machine is
able to detect the magnetic fields
and identify which part of the
body has more electrical activity.
Human brain is an intricate pattern
of electromagnetic fields.
The electrical impulses cause the brain
to function and if two magnetic fields
intersect each other there is intrusion,
which is unhealthy for the human brain.
Optics
Optics has been often
associated with the making of
different types of lenses for
telescopes, microscopes or
eyeglasses however the term
optics broadly discusses the
study of light’s behaviour and
its interactions with matter.
The development of different optical
tool impelled the scientists to
closely research the behaviour of
light which the tools directed.
Optics can be broadly categorized
into three subfields of research:
a) Geometrical optics which
is the study of light as rays
b) Physical optics which is
the study of light as waves
c) Quantum optics which is the
study of light as particles
a) Geometrical optics
Initial optics researchers used
geometry to show this view of light.
Light is expected to
travel along rays which
are line segments
that are straight in
free space but might
alter direction, or even
bend, if it comes in
contact with matter.
There are two laws which
explain about what
happens if light comes
in contact with surface.
Law of reflection according to which if
light comes in contact with a flat surface
the angle of incidence of the ray is
equivalent to the angle of reflection.
Law of refraction which states the
way in which a light ray alters its
path if it crosses a planar boundary
from one substance to another.
A direct result of this ‘bending’
of light rays is if something
is half immersed in a glass of
water will look like it is bent.
The behaviour of optical devices
like microscopes and telescopes can
be ascertained with the help of the
laws of reflection and refraction.
The paths of various rays
can be traced to see their
magnification, relative orientation
and how images are formed.
b) Physical optics
The study of the wave properties
of light can be termed
as physical optics and be
categorized in three categories
Interference is the capacity of a wave to
obstruct with itself, crafting contained
areas where the field is consecutively
extremely dark and extremely bright.
Diffraction is the capacity
of the waves to curve round
corners and disperse after
passing via an aperture
Polarization denotes the characteristics of
light connected to the transverse nature.
Anyone can determine the
wave nature of sound
without the use of any
scientific tools.
For example, in diffraction, if you stand
facing your friends building and he shouts
back at you, his shouts
will clearly be audible
to you because of
direct line of sight.
The sound waves moderately
cover the corners of
the building enabling you
to hear your friend.
Wave nature of light is
not ostensible because
of the wavelength of
every wave in each case.
For sound to be audible the
wavelength ranges from
millimetres to 20 meters
whereas for visible light the
wavelength is only 0.0000005
meters, which is very
small in comparison to what
a human eye can observe.
c) Quantum optics
Quantum optics is the part
of quantum physics that is
involved in the study of interaction
of photons with matter.
With conclusions from
quantum electrodynamics,
quantum optics can
be interpreted in
the form of obliteration and creation of
photons, explained by the field operators.
The approach enables the use
of particular arithmetical
approaches which are useful
in evaluating the behaviour
of light, though if it
represents something that is
physically taking place is
a point still in debate.
The application of quantum optics
can be seen in masers and lasers.
The light which is emitted from
these machines is in rational
state, which means the light
looks like a sinusoidal wave.
These three types of quantum
are still being studied.
In order to better the geometric models so
that there is a better overlap with the
wave theory of light, researchers are
having continued studies in this field.
Engineering and pure science
are thoroughly related with
physical optics and the
magnitudes of wave of nature of
light are still being unfolded
and many optical machines
are being built to take
advantage of this wave nature.
Quantum optics is an important
thing to understand
the theory of quantum
mechanics although
numerous hypothetical uses
like quantum cryptography,
quantum computing are
being discovered.
Special relativity
Special relativity also
referred to as special
theory of relativity in
physics, is the commonly
recognized and experimentally
established physical
theory about the connection
between time and space.
According to Albert Einstein’s academic
treatment it is based on two hypotheses.
The laws of physics are invariant;
which is identical, in all inertial
The speed of light in vacuum
is same for all those who
observe, irrespective of the
motion of the source of light.
The laws were initially suggested by
Albert Einstein that was published
in 1905, in paper "On the
Electrodynamics of Moving Bodies".
The discrepancy of Maxwells equations of
electromagnetism with Newtonian mechanics
and the absence of investigational
validation for a theorize luminiferousaether
is what caused the progress of special
relativity, that amends mechanics to take
care of situations which involve motions
which is nearing the speed of light.
Today, special relativity is a precise
model of motion at any given speed.
Even if the model of Newtonians mechanics
continues to be useful, as it its precise
and simple, approximately atminor
velocities relative to the speed of light.
Special relativity suggests a
broad range of magnitudes,
which have been experimentally
proved, including time
dilation, length contraction,
relativity of simultaneity,
universal speed limit and
mass-energy equivalence.
It has taken the place of conservative
belief of a complete universal time
with the idea of a time which depends on
reference frame and spatial position.
Instead of an invariant
time gap between two
events there is an invariant
space-time interval.
If combined with other laws of
physics there are two assumptions
of special relativity which
foretell the equivalence of
energy and mass, which is conveyed
in the energy-mass equivalence
formula E = mc2 , c being the
speed of light in vacuum.
An important aspect of special relativity
is that the Galilean transformations
of Newtonian mechanics have taken the
place of Lorentz transformations.
There cannot be a definition for space and
time if they are separated from each other.
Infact space and time are
intertwined in a single
continuum which is
referred to as space-time.
Events which occur at the same
time for a particular observer
may happen at different times
for a different observer.
This is a "special" theory and
implies especially when the
curvature of space-time is
negligible because of gravity.
Albert Einstein framed
general relativity in 1915.
Disagreeing certain out-dated
descriptions special relativity
has the ability of managing
accelerated frames of references.
Today Galilean relativity is reflected
an estimate of special relativity
which is effective for low speeds,
special relativity is reflected
as estimate of general relativity
which is effective for gravitational
fields( in conditions of free
fall and a very small scale).
While general relativity includes
non-Euclidean geometry so
as to characterize the gravitational
effects as the geometric
curvature of space-time, special
relativity is contained
to the flat space-time referred
to as Minkowski space.
A close by Lorentz invariant frame
which stands by special relativity
can be described at small gauges
even in curved space-time.
Earlier Galileo Galilei
has already hypothesized
that there is no
definite and complete
state of rest through a principle which is
known as Galileo’s principle of relativity.
Albert Einstein stretched
this principle so
that it took into account
the speed of light,
an occurrence that had
been recently uncovered
in the Michelson-Morley
experiment.
He also hypothesized that it is
applicable for all the laws of
physics inclusive the two laws of
electrodynamics and mechanics.
Although the fundamentals of physics
might not be quite understood by
everyone but it is something which is
unknowingly used in our daily life.
No matter how hard the subject may be to
learn but it helps us make our lives easy.
It plays an important role in the
history of mankind and will continue
to hold a pivotal place in
futuristic science and technology.
For those who admire the subject
physics can be an intellectual
experienced and when studied
deeper will never stop to amaze.
It is the most basic
amongst all the sciences
and other sciences like
chemistry, biology,
geology or cosmology can
be understood by the
theories which have been
developed in physics.
Most of the tools on which the
progress of technology and
science are dependant have
been produced by physics.
The presence of physics can
be felt all around you.
From checking your blood pressure to getting
an x-ray done, from petrol required to run
your vehicle to electricity
at your home, from
an email that your send from
your computer or laptop
to a smartphone that
you love to flash,
from an aeroplane
to a ship, from a DVD
to a television and even the house that you
live in is built with the help of physics.
A country’s development highly
depends on how strong the
nation’s team of physics
researches or institutes are.
Nations understand the importance of
physics and which is why they encourage
researches which in turn help in the
overall development of the country.
Understanding physics
is important and easy.
