Physics Part 2 - Quick Guide


Physics - Introduction


  • Physics is one of the most significant disciplines of natural science, which describe the nature and properties of matters.

  • The term ‘physics’ is derived from the Ancient Greek word i.e. ‘phusikḗ’ meaning ‘knowledge of nature’.

Physics Introduction


  • Physics is the branch of natural science that studies the nature and properties of matter and energy.

  • The significant subject matter of physics includes mechanics, heat & thermodynamics, optics, sound, electricity, magnetism, etc.

  • Development of Physics also makes significant contributions in the field of technologies. For example, inventions of new technology such as television, computers, cell phone, advanced home appliances, nuclear weapons, etc.

Development of Physics

  • During the ancient period, the development of physics took place with the development of astronomy.

  • However, during the medieval period, a notable work of the Arab writer and scientist Ibn Al-Haitham revolutionized the concept of physics.

  • Ibn Al-Haitham had written a book in seven volumes namely “Kitāb al-Manāẓir “also known as “The Book of Optics.”

  • In this book, Ibn Al-Haitham disprove the ancient Greek concept of vision and introduced a new theory.

  • Ibn Al-Haitham had also introduced the concept of the pinhole camera.

  • During the late medieval period, Physics became a separate discipline of the natural science.

  • In making physics as a separate discipline, the major contributions were given by the European scientists.

  • These modern European scientists had been introduced different concepts of physics and discovered and invented many new technologies.

  • For example, Copernicus replaced the ancient view of geocentric model and introduced the heliocentric concept; Galileo invented the telescopes, Newton discovered the laws of motion and universal gravitation, etc.

  • The era of modern physics came with the discovery of quantum theory by Max Planck and theory of relativity by Albert Einstein.

Physics Scientists
  • After development of modern physics, the ear of applied physics commenced where emphasis is given on ‘research’ on a particular use.

  • The particle physicists have been consistently designing and developing the high energy accelerators, detectors, and computer programs.

  • Nuclear physics is another branch of modern physics that studies the constituents and interactions of the atomic nuclei.

  • The most widely known inventions and applications of nuclear physics are the generation of nuclear power and the development of nuclear weapons technology.

  • At present, the physic scientists are working on the concept of high-temperature superconductivity.

Physics - Branches

The following table illustrates the major branches and their sub-branches) of physics −

Branch/Field Sub-branch/Sub-field
Classical mechanics
Newtonian mechanics
Analytical mechanics
Celestial mechanics
Applied mechanics
Analytical mechanics
Dynamics (mechanics)
Elasticity (physics)
Fluid mechanics
Thermodynamics and statistical mechanics Heat
Optics Light
Condensed matter physics
Solid state physics
High pressure physics
Surface Physics
Polymer physics
Atomic and molecular physics
Atomic physics
Molecular physics
Chemical physics
Gravitation physics
High-energy astrophysics
Planetary astrophysics
Plasma physics
Solar physics
Space physics
Stellar astrophysics
Nuclear and particle physics
Nuclear physics
Nuclear astrophysics
Particle physics
Particle astrophysics
Applied Physics
Chemical Physics
Communication Physics
Engineering physics
Laser Physics
Medical physics
Physical chemistry
Plasma physics
Quantum electronics

Physics - Acoustics


  • Acoustics is an interdisciplinary science that studies different mechanical waves passing through solid, liquid, and gases.

  • Basically, acoustics is the science of sound that describes the generation, transmission, and effects of sounds; it also, including biological and psychological effects sound

  • Likewise, acoustics studies vibration, sound, ultrasound, infrasound.

  • Acoustics
  • The term "acoustic" is a Greek word i.e. ‘akoustikos,’ which means "of or for hearing, ready to hear."

  • These days, acoustics technology is very much applicable in many industries specially to reduce the noise level.


  • The person who is an expert in the field of acoustics is known as acoustician.

  • There are a variety of acoustics fields of study. For example, the production sound, control of sound, transmission of sound, reception of sound, or effects of sound on human beings as well as on animals.

Types of Acousticians

  • Following are the major types of acousticiansn −

  • Bioacoustician − The expert of this field researches and studies birds of a given geographic region to determine that the man-made noise changes their behavior.

  • Biomedical Acoustician − The expert of this field researches and develop medical equipment to treat kidney stone.

Types of Acousticians
  • Underwater Acoustician − The expert of this field research and design sophisticated sonar hardware that explores the ocean floor.

  • Audiologist − The expert of this field diagnose hearing impairments.

  • Architectural Acoustician − The expert of this field designs an opera house to manage the high pitch sound (inside the house).

Fields of Acoustics

  • Following are the major fields of acoustics.

  • General Acoustics − This field of acoustic studies about the sounds and waves.

  • Animal Bioacousticians − This field of acoustic studies how animals create, use, and hear sounds.

  • Architectural Acoustics − This field of acoustic studies about the building designs to have the pleasing sound quality and safe sound levels.

  • Medical Acoustics − This field of acoustic researches and studies the use acoustics to diagnose and treat various types of illnesses.

  • Archaeoacoustics − This field of acoustic studies sound systems of archaeological sites and artefacts.

  • Psychoacoustics − This field of acoustic studies – how human beings respond to a particular sound.

Physics - Biophysics


  • Biophysics is a fascinating term for the biology researchers as well as for the physics researcher, as it creates bridge between these two subjects of science.

  • Biophysics (also known as biological physics) is basically an interdisciplinary approach to study the biological systems. It is uses physics technology to understand the biological systems.

  • Likewise, biophysics integrates all levels of biological organization, i.e. from molecular level to organismic and population level.

  • In 1892, first time Karl Pearson used the term ‘Biophysics.’

Subject Matter of Biophysics

  • Biophysicists study the life (basically human life); starting from the cellular organs (such as ribosome, mitochondria, nucleus, etc.) to organisms, and their environment.

  • With the advancement of technology, the scientists and researchers of both the disciplines (namely Biology and Physics) started exploring a different level of life to understand how actually biological system works.

  • The biophysicists largely research on the following types of questions −

    • How do the cells of nervous system communicate?

    • How and why do viruses invade cells?

    • What is the functionality of protein synthesis?

    • How do plants harness sunlight to make their food?

Advantages of Biophysics

  • The study of life at molecular level helps to understand many phenomena of a human body including various diseases and their treatment.

  • Biophysics helped to understand the structure and function of DNA.

DNA Structure
  • The study of biophysics helps to understand the various elements of bio-chemistry.

  • Biophysics also help to understand the structure and various functionality of protein.

Sub-Branches of Biophysics

  • Following are the major sub-branches of biophysics −

    • Biochemistry

    • Physical chemistry

    • Nanotechnology

    • Bioengineering

    • Computational biology

    • Biomechanics

    • Bioinformatics

    • Medicine

    • Neuroscience

    • Physiology

    • Quantum biology

    • Structural biology

Technology of Biophysics

  • Following are the major technologies used in Biophysics −

    • Electron microscope

    • X-ray crystallography

    • NMR spectroscopy

Technology of Biophysics
  • Atomic force microscope (AFM)

  • Small-angle scattering (SAS) technology

Physics - Econophysics


  • Econophysics is an interdisciplinary science that studies the dynamic behavior of finance and economic markets.

  • In order to solve the problems of economics and also to understand the dynamic behavior of the market, the econo-physicists develop applied theories.

  • Econophysics, sometime, is also known as the physics of finance.

  • It applies statistical mechanics for the economic analysis.

Econophysics Questions

  • The econophysics questions include −

    • How to accurately measure and explain the significant properties of market dynamics?

    • How to stabilize the markets?

    • What are the different behaviors in different markets?

Tools of Econophysics

  • The fundamental tools of econophysics are −

    • Probabilistic method

    • Statistical method

    • These two methods are borrowed from statistical physics.

  • Other tools taken from Physics

    • Fluid dynamics

    • Classical mechanics

    • Quantum mechanics

Models of Econophysics

  • Following are the major models those are used in Econophysics −

    • Percolation Model

    • Percolation Model
    • Kinetic exchange models of markets

    • Chaotic models

    • Information theory

    • Random matrix theory

    • Diffusion theory

Physics - Geophysics


  • Geo-physics is a specialized branch of Earth science that studies the physical properties and physical process of the Earth.

  • Geophysicists use some quantitative methods and advance technology to analyze the Earth’s properties and process.

  • Technology of geophysics is used to locate mineral resources, mitigate natural hazards, and protection of the environment.

  • Geophysics has been carved out as an independent discipline from different subjects, such as, geology, physical geography, astronomy, meteorology, and physics.

Elements of Geophysics

  • Major elements those are studied under the geophysics are −

    • Shape of the Earth

    • Gravitational force of the Earth

    • Magnetic Fields of the Earth

    • Internal structure of the Earth

    • Composition of the Earth

    • Movement of the Earth’s plate (plate tectonics)

    • Volcanic activity

    • Rock formation

    • Water cycle

    • Fluid dynamics, etc.

Problems that Geophysicists Address

  • Following are the problem areas that geophysicists address −

    • Building highways and bridges

    • Mapping and exploration of mineral resources

    • Mapping and exploration of water

    • Mapping the earthquake and volcanic regions

    • Geological mapping

    • Problems that Geophysicists Address
    • Archeology discovery

    • Construction of dam and its safety

    • Forensic discovery (finding the buried dead bodies)

Techniques and Technology of Geophysics

  • Following are the major techniques and technology of geophysics −

    • Geo-magnetism

    • Electromagnetics

    • Polarization

    • Seismic technology

    • Ground penetrating radar (GPR), etc.

Benefits of Geophysics

  • Following are the major benefits of geophysics −

    • Researching and studying archeological sites without destroying them

    • Designing environmental friendly urban architecture

    • Locating and judiciously exploiting natural resources

    • Helping in mitigation of natural hazards such as landslide, earthquake, etc

Physics - Nanotechnology


  • Nanotechnology is the science of management and manipulation of atoms and molecules to design a new technology.

  • Nanotechnology is the supramolecular technology, which means, it is the engineering of functional systems at the molecular or supramolecular scale.

  • Interestingly, one nanometer (nm) is equal to one billionth, or 10−9, of a meter.

  • The concept and idea of nanotechnology original discussed first time in 1959 by Richard Feynman, the renowned physicist.

  • Richard Feynman in his talk “There's Plenty of Room at the Bottom,” described the feasibility of synthesis via direct manipulation of atoms.

  • However, in 1974, the term "Nano-technology" was first used by Norio Taniguchi.

Major fields of Research

  • Following are the major fields in which nanotechnology is being researched −

    • Advance computing − Developing super computer

    • Electronics − developing conductors and semi-conductors

    • Medicines − Developing technology to treat cancer (especially breast cancer)

    • Textile Engineering − Nanofabrication, etc.

Application of Nanotechnology

  • Following are the major application of nanotechnology −

    • Manufacturing of lifesaving medical robots

    • Making available the networked computers for everyone in the world

    • Plant networked cameras to watch everyone’s movement (very helpful for the administrative service and maintaining the law and order.

    • Manufacturing untraceable weapons of mass destruction.

    • Swift inventions of many wonderful products useful in everyday life.

Application of Nanotechnology
  • Likewise, the molecular technology has range of potentials that benefit to humankind; however, at the same time, it also brings severe dangers. Untraceable weapon of mass destruction is an ideal example of its deadliness.

Major Branches of Nanotechnology

  • Following are the major branches of nanotechnology −

    • Nanoelectronics

    • Nanomechanics

    • Nanophotonics

    • Nanoionics

Contributory Disciplines of Nanotechnology

  • Following are the major disciplines that integrated into the development of science of nanotechnology −

    • Surface science

    • Organic chemistry

    • Molecular biology

    • Semiconductor physics

    • Microfabrication

    • Molecular engineering

Implication of Nanotechnology

  • Every coin has two faces, similarly, the application of nanotechnology at industrial scale i.e. manufacturing nanomaterials might have negative implications on human health as well as on the environment.

  • The workers who especially work in such industry where non materials are used, are more vulnerable, as they inhale airborne nanoparticles and nanofibers. These Nano materials may lead to a number of pulmonary diseases, including fibrosis, etc.

Physics - Neurophysics


  • The branch of medical physics that studies the nervous system, such as brain, spinal cords, and nerves, is known as neurophysics.

  • The researchers of neurophysics research the basic physical basis of the brain to understand its different functionality.

  • Neurophysicists also study the cognitive process of a human being.

  • The term ‘neurophysics’ was originally taken from Greek term namely ‘neuron’ meaning "nerve" and ‘physis’ meaning ‘nature,’ or ‘origin.’ So, neurophysics is basically concerned with the study of the workings of the nervous system.

  • Furthermore, the integrity of neural physics also postulates that the whole universe is in living, but in a way that is beyond the conception of biological organisms.

Neurophysics Therapy

  • Neurophysics therapy is highly sophisticated exercise-based method of treatment. Such technique treats a wide range of diseases and its successful rate is also high.

Neurophysics Therapy
  • Some of the significant diseases that can be treated through neurophysics therapy are listed below −

    • Arthritis

    • Athletic performance

    • Metabolic disorders

    • Rehabilitation

    • Bipolar disorder

    • Migraine

    • Chronic pain

    • Motor neuron disease

    • Degenerative disorders

    • Depression (clinical; reactive)

    • Muscular dystrophy

    • Drug addiction

    • Epilepsy

    • Osteoarthritis

    • Parkinson’s disease

    • Vestibular disorders

    • Hereditary spastic paraplegia, etc.

  • Furthermore, the practice of neurophysics facilitates us to remain healthy and function better in everyday life, as it provides the technique i.e. how to disperse stress evenly in your body and not allowing it to become isolated.

Physics - Psychophysics


  • Psychophysics is basically an interdisciplinary branch of psychology and physics; it studies the relationship between physical stimuli and the sensations along with the perceptions they produce.

  • The psychophysicists analyze the perceptual processes by studying the effect on a behavior; further, they also study the systematically varying properties of a stimulus along one or more physical dimensions.

  • The concept of psychophysics was first time used in 1860 by Gustav Theodor Fechner in Leipzig, Germany.

  • Fechner published his research namely ‘Elemente der Psychophysik’ (i.e. Elements of Psychophysics).

Terms of Psychophysics

  • Following are the commonly used terms in psychophysics −

    • Signal detection theory − It explains the interaction of the sensory capabilities and the decision making elements in detecting the stimulus.

    • ‘Ideal observer analysis − It is a technique for investigating i.e. how information has processed in a perceptual system.

    • Difference thresholds − It helps to differentiate two stimuli. This point is termed just-noticeable difference.

    • Absolute threshold − The point at which the person first detects the stimulus strength i.e. presence of stimulus.

    • Scaling − It uses rating scales to allocate relative values.

Modern Approaches of Psychophysicists

  • Modern Psychophysicists research on −

    • Vision

    • Hearing

    • Touch (or sense)

  • Based on these, psychophysicists measure what the perceiver's decision extracts from the stimulus.

Application of Psychophysicists

  • In the present world, psychophysics is commonly applied to treat many of psychological problems.

Physics - Astrophysics


  • Astrophysics is one of the oldest branches of natural science or astronomy.

  • Astrophysics is being used as the basis for making calendars and navigation.

  • Astrophysics is also being used as an important input for religions because since the beginning, astrologers taking help of this science to in their astrological works.

  • The modern branch of astrophysics namely ‘Theoretical astrophysics,’ describes the functions and behaviors of celestial bodies.

  • Theoretical astrophysics uses a wide variety of tools such as analytical models (e.g., polytropes to approximate the behaviors of a star) and the computational numerical simulations.

Topics of Astrophysics

  • Following are the major topics of astrophysics (modern) −

    • Solar System (formation and evolution);

    • Stellar dynamics and evolution;

    • Galaxy formation and evolution;

    • Magneto-hydrodynamics;

    • Origin of cosmic rays;

    • General relativity and physical cosmology.

Major Works in Astrophysics

  • Following are the major developments in Astrophysics −

    • By using telescope, Galileo had performed the first astronomical studies in 1609. Galileo discovered sun spots and four satellites of Saturn.

    • Based on observations of Tycho Brahe, Kepler had developed three laws of planetary motions.

    • In 1687, Newton had introduced the laws of motion and gravitation.

    • By giving the theory of relativity in 1916, Einstein provided the first consistent basis to study cosmology.

    • In 1926, Hubble discovered that the galaxies are recessing and their velocity is increasing with the distance. It means, the universe is expanding and extrapolating this expansion back in time led to the concept of ‘Big Bang.’

    • In 1974, Hulse and Taylor discovered a binary system of two pulsars that proved the existence of gravitational waves.


  • Astronomy the oldest branch of is a natural science that studies celestial objects their functional phenomena.

  • In order to explain the origin of the celestial bodies, their evolution, and phenomena, the different disciplines of science such as physics, chemistry, mathematics are applied.

  • The objects of study are −

    • Planets

    • Satellites or moons

    • Stars

    • Galaxies

    • Comets, etc.

  • Some of the important phenomena those are studied are −

    • Supernova explosions

    • Gamma ray bursts, and

    • Cosmic microwave background radiation, etc.

  • During the 20th century, based on approach of study, the astronomy is categorized as −

    • Observational astronomy − Based on the approach and methods, observational astronomy scientists observe, collect, and analyze the celestial data. To analyze the data, they use basic principles of physics.

    • Theoretical astronomy − The scientists of theoretical astronomy attempt to develop computer or analytical models in order to describe the celestial bodies and their functionalities.

  • Likewise, astronomy incorporates the diverse disciplines such as celestial navigation, astrometry, observational astronomy, etc.; this is how astrophysics is profoundly related to astronomy.

Physics - Measurement Units

The following table illustrates the major measuring units in physics −

Mass And Related Quantities
Quantity Symbol Unit
Density ρ kg.m-3
Volume V m-3
Force F Newton (N)
Torque M N.m
Pressure P Pascal (Pa)
Dynamic viscosity η Pa.s
Acoustic pressure p Pascal (pa)
Dynamic volume v m3
Electricity and Magnetism
Quantity Symbol Unit
Power P watt (W = J/s)
Energy W joule (J = N.m)
Magnetic field strength H ampère per metre (A/m)
Electric field E volt per metre (V/m)
quantity of electricity Q coulomb (C = A.s)
Electrical resistance R ohm (Ω = V/A)
electrical capacitance C farad (F = C/V)
Potential difference U volt (V = W/A)
International System of Units
meter m Length
kilogram kg Mass
second s Time
ampere A Electric Current
kelvin K Thermodynamic temperature
mole mol Amount of substance
candela cd Luminous intensity
radian rad Angle
steradian sr Solid Angle
hertz Hz Frequency
newton N Force, weight
pascal Pa pressure, stress
joule J energy, work, heat
watt W Power, radiant, flux
coulomb C Electric charge
volt V Voltage, electromotive force
farad F Electric capacitance
ohm Ω Electric resistance
tesla T Magnetic flux density
degree Celsius 0C Temperature
becquerel Bq radioactivity
henry H Magnetic induction
Angstrom Å Wave length

Conversion of Units

Unit I Value in another unit
1 Inch 2.54 centimeter
1 Foot 0.3048 meter
1 Foot 30.48 centimeter
1 Yard 0.9144 meter
1 Mile 1609.34 meter
1 Chain 20.1168 meter
1 Nautical mile 1.852 kilometer
1 Angstrom 10-10 meter
1 Square inch 6.4516 square centimeter
1 Acre 4046.86 square meter
1 grain 64.8 milligram
1 dram 1.77 gm
1 ounce 28.35 gm
1 pound 453.592 gram
1 horse power 735.499 Watt

Physics - Major Instruments and Their Uses

The following table illustrates the major scientific instruments and their uses −

Instrument Use
Accelerometer Measures acceleration
Altimeter Measures altitude of an aircraft
Ammeter Measures electric current in ampere
Anemometer Measures wind speed
Barometer Measures atmospheric pressure
Bolometer Measures radiant energy
Caliper Measures distance
Calorimeter Measures heat (in chemical reaction)
Crescograph Measures growth in plant
Dynamometer Measures torque
Electrometer Measures electric charge
Ellipsometer Measures optical refractive indices
Fathometer Measures depth (in sea)
Gravimeter Measures the local gravitational field of the Earth
Galvanometer Measures electric current
Hydrometer Measures specific gravity of liquid
Hydrophones Measures sound wave under water
Hygrometer Measures atmospheric humidity
Inclinometer Measures angel of slope
Interferometer Infrared light spectra
Lactometer Measures purity of milk
Magnetograph Measures magnetic field
Manometer Measures pressure of gas
Ohmmeter Measures electric resistance
Odometer Measures distance travelled by a wheeled vehicle
Photometer Measures intensity of light
Pyrometer Measures temperature of a surface
Radiometer Measures intensity or force radiation
Radar Detects distance object, e.g. aircraft, etc.
Sextant Measures angle between two visible objects
Seismometer Measures motion of the ground (earthquake/seismic waves)
Spectrometer Measures spectra (light spectrum)
Theodolite Measures horizontal and vertical angles
Thermopile Measures small quantities of radiant heat
Thermometer Measures temperature
Udometer Measures amount of rainfall
Viscometer Measures the viscosity of fluid
Voltmeter Measures volt
Venturi meter Measures flow of liquid

Inventions & Inventors in Physics

The following table illustrates the major inventions and their inventors in physics uses −

Invention Inventor
Centigrade scale Anders Celsius
Watch Peter Henlein
Radio Guglielmo Marconi
Telephone Alexander Graham Bell
Electricity Benjamin Franklin
Electric Light Bulb Thomas Edison
Thermometer Galileo Galilei
Telescope Hans Lippershey and Zacharias Janssen; later Galileo
Telegraph Samuel Morse
Cosmic Rays Victor Hess (but the term ‘cosmic rays’ first used by Robert Millikan
Automobile Karl Benz
Magnetic Tape Fritz Pfleumer
Transformer Michael Faraday (later Ottó Titusz Bláthy)
Electromagnetic Induction Michael Faraday
Quantum mechanics Werner Heisenberg, Max Born, and Pascual Jordan
Wave mechanics Erwin Schrödinger
Nuclear Reactor Enrico Fermi
Fuel Cell William Grove
Airplane Wright Brothers
Barometer Evangelista Torricelli
Camera Nicéphore Niépce
Diesel Engine Rudolf Diesel
Helicopter Igor Sikorsky
Dynamite Alfred Nobel
Lift Elisha Otis
Laser Printer Gary Starkweather
Mobile Phone Martin Cooper
Printing Press Johannes Gutenberg
Video Games Ralph Baer
Steam engine Thomas Newcomen
Railway Engine George Stephenson
Jet Engine Frank Whittle
Seismograph John Milne
Electric Generator Michael Faraday
Television John Logie Baird
Refrigerator William Cullen (later Oliver Evans)
Carburetor Luigi De Cristoforis & Enrico Bernardi
Air Brake George Westinghouse
Atomic bomb Robert Oppenheimer, Edward Teller et al
Air conditioner Willis Carrier
Machine Gun Sir Hiram Maxim
Radar Sir Robert Alexander Watson-Watt
Submarine Cornelius Drebbel (later) David Bushnell
First military submarine Yefim Nikonov
Transistor John Bardeen, Walter Brattain, and William Shockley
Galvanometer Johann Schweigger
Laser Theodore H. Maiman (first demonstrated)
Neon lamp Georges Claude
Rocket Engine Robert Goddard
Typewriter Christopher Latham Sholes

Physics - Timeline

The following table illustrates the major events (along with probably time period) that occurred in physics −

Event Time Period
Babylonians collected information of planets and stars 2000 BC to 1600 BC
Ancient Indians explained the evolution of universe and also explained about sun, moon, earth, and other planets 1500 BC to 1000 BC
Greek philosopher Anaxagoras explained the physical universe During 5th Century BC
Two Greek philosophers namely Leucippus and Democritus established the school of Atomism During 5th Century BC
Aristotle, the Greek philosopher, described a geocentric universe During 4th Century BC
The Greek philosopher Heraclides explained the motions of planets and stars During 4th Century BC
Eratosthenes, the Greek mathematical geographer proposed the round shape of the Earth During 3rd Century BC
Hipparchus was the first who measured the precession of the equinoxes During 2nd Century BC
Based on Aristotelian ideas, the Roman-Egyptian mathematician and astronomer Ptolemy described a geocentric model During 2nd Century AD
The Indian astronomer and mathematician Aryabhata described the earth’s elliptical orbit around the sun and its axis (heliocentric view) During 5th Century AD
Brahmagupta, the Indian mathematician and astronomer noticed the gravity of earth During 7th Century AD
Abu al-Rayhan al-Biruni, the Persian astronomer described the Earth's gravitation. During 11th Century AD
Nicolaus Copernicus, the Polish astronomer and polymath explained the heliocentric principal scientifically During 16th Century Ad
Johannes Kepler, the German mathematician and astronomer propounded Laws of Planetary Motion During 17th Century AD
Galileo Galilei, the Italian mathematician and physicist invented an astronomical telescope During 17th Century AD
Sir Isaac Newton, the English mathematician, astronomer, and physicist propounded Laws of Motions and Universal Law of Gravitation During 17th Century AD
Emanuel Swedenborg first suggested parts of the nebular hypothesis 1734 AD
Immanuel Kant publishing “Universal Natural History and Theory of the Heavens,” and explained nebular hypothesis 1755 AD
Max Planck, the German physicist described the law of black body radiation and led the foundation of quantum physics During 20th Century AD
Albert Einstein, the German physicist propounded the theory relativity During the 20th Century AD
Max Planck introduced formula for Black Body radiation 1900 AD
Kamerlingh Onnes experimented and noticed superconductivity 1911 AD
Wolfgang Pauli, the Austrian theoretical physicist proposed an important quantum mechanical principle namely the ‘Pauli exclusion principle’ 1925 AD
Georges Lemaître proposed Big Bang theory 1927 AD
Edwin Hubble explained the expanding nature of universe (known as Hubble’s Law) 1929 AD
Otto Hahn discovered nuclear fission discovered 1938 AD
Black Hole Entropy 1972 AD
Richard Feynman proposes quantum computing 1980 AD
Theory of cosmic inflation 1981 AD
Top quark discovered 1995 AD
Gravitational waves detected 2015 AD

Physics - Unsolved Problems


  • The meaning of unsolved problems is – the developed theories and models are incapable to explain some ongoing phenomenon or science experiments are not able to rectify the concerned phenomena.

  • The following table illustrates the major unsolved problems in physics −

Quantum Physics
Is there a single possible past?
Is the present time physically distinct from the past and future?
How is quantum information stored as a state of a quantum system?
Is there any feasibility to reconcile time with general relativity?
Why is the distant universe so homogeneous when the Big Bang theory appears to predict larger measurable anisotropies of the night sky than the observed one?
Is the universe heading towards a Big Freeze, a Big Crunch, a Big Rip, or a Big Bounce?
What is the size of the whole universe?
What is the identity of dark matter?
What is the probable cause of the observed accelerated expansion of the universe?
Black holes Is there any way to probe the internal structure of black holes somehow?
Extra dimensions Does nature have any fifth space time dimensions?
Particle physics
Is the proton fundamentally stable?
Did particles that carry "magnetic charge" exist in the past?
What is the electric charge radius of the proton?
How does electric charge differ from gluonic charge?
How does the Sun generate its periodically reversing large-scale magnetic field?
Why & how is the Sun's corona (i.e. atmosphere layer) much hotter than the Sun's surface?
What is responsible for the numerous interstellar absorption lines discovered in astronomical spectra?
What is the origin of the M-sigma relation between the supermassive black hole mass and the galaxy velocity dispersion?
What is the precise mechanism by which an implosion of a dying star becomes an explosion?
What is the source of space roar?
Where did Earth's water come from?
What is the nature of neutron stars and dense nuclear matter?
What is the origin of the elements in the cosmos?
Optical physics What is the momentum of light in optical media?
How do genes govern human body, withstanding different external pressures and internal stochasticity?
What are the quantitative properties of immune responses?
What are the basic building blocks of immune system networks?
Condensed matter physics
Is topological order stable at non-zero temperature?
Is it feasible to develop a theoretical model to describe the statistics of a turbulent flow?
What causes the emission of short bursts of light from imploding bubbles in a liquid when excited by sound?
What is the nature of the glass transition between a fluid or regular solid and a glassy phase?
What is the mechanism that causes certain materials to exhibit superconductivity at temperatures much higher than around 25 kelvin?
Is it possible to make a material that is a superconductor at room temperature?

Terminologies in Physics

The following table illustrates the major ‘Terms’ in physics −

Terms Meaning
Absolute Zero It means the theoretical lowest possible temperature
Acoustics The branch of physics that studies sound
Adhesion The propensity of dissimilar particles or surfaces to adhere or cling to one another
Alpha particles It consists of two protons and two neutrons bound together into a particle (i.e. identical to a helium nucleus)
Amorphous solid It is non-crystalline solid, which has no definite shape
Amplitude It is height of a wave, which is measured from its center position
Angstrom (Å) It is an unit of linear measurement that measures micro-particles
Atomic mass unit It is one-twelfth the mass of an atom of the isotope 12⁄6C
Beta Particles It is high-energy, high-speed electrons or positrons emitted by the particular types of radioactive nuclei
Big Bang The cosmological model that explains the early development of the Universe
Binding energy The mechanical energy that is required to disassemble a whole into separate parts
Black hole A region of space-time, which gravity is very powerful and prevents anything, including light, from escaping
Boson It is one of two classes of elementary particles; second one is fermions
Cathode An electrode through which electric current flows out of a polarized electrical device
Centrifugal force Center fleeing
Centripetal force Center seeking
Condensed matter physics A branch of physics that studies the physical properties of condensed phases of matter
Convection The process of transfer of heat by the actual transfer of matter
Crest The point on a wave with the maximum value
Doppler effect The change in frequency of a wave for an observer moving relative to its source
Ductility It is the property of solid material that deform under tensile stress
Elasticity It is physical property of materials which return to their original shape once they are deformed.
Electromagnet A typical magnet in which the magnetic field is produced by passing the electric current
Entropy A quantity that describes the randomness of a substance or a system
Escape velocity The speed at which the kinetic energy and the gravitational potential energy of an object is zero. Likewise, the escape velocity is the speed required to "break free" from a gravitational field without further propulsion
Free fall Any motion of a body where its weight is the only force acting upon it
Ice point A transitional phase of a substance from a liquid to a solid.
Inertia It is the tendency of an object to resist any change in its motion
Kinematics Geometry of motion
Neutrino An electrically neutral subatomic particle
Photon It is an elementary particle
Quark It is an elementary particle and a fundamental constituent of matter
Redshift Shifting towards the red end of the spectrum
Screw It is a mechanism that converts rotational motion to linear motion
Siphon An inverted U tube that causes a liquid to flow uphill without support of any pump. It is basically powered by the fall of the liquid as it flows down the tube under the force of gravity
Sublimation It is a process of transformation in which solid directly changed to gas without passing through an intermediate liquid phase
Supernova A stellar explosion, which is more energetic than a nova
Vector Vector is a quantity, which has both magnitude and direction
White dwarf It is a stellar remnant, which is composed largely of electron-degenerate matter. These are very dense
Wind shear It is the difference between wind speed and direction over a relatively short distance in the atmosphere

Major Theories and Laws in Physics

The following table illustrates the major theories in Physics along with their respective fields −

Theory Filed
Standard Model Nuclear Particle Physics
Quantum field theory
Quantum electrodynamics
Quantum chromodynamics
Electroweak theory
Effective field theory
Lattice field theory
Lattice gauge theory
Gauge theory
Grand unification theory
Superstring theory
Quantum optics Optical physics
Quantum chemistry Atomic and molecular physics
Quantum information science
BCS theory Condensed matter physics
Bloch wave
Density functional theory
Fermi gas
Fermi liquid
Many-body theory
Statistical Mechanics
Big Bang Astrophysics
Cosmic inflation
General relativity
Newton's law of universal gravitation
Lambda-CDM model
Newton's Law of universal gravitation Mechanics
Newton's Laws of motion
Ampère's circuital law Current Electricity
Birch's law Geophysics
Bell's theorem Quantum mechanics
Beer–Lambert law Optics
Avogadro's law Thermodynamics
Boltzmann equation
Boyle's law
Coulomb's law Electrostatics and Electrodynamics
Doppler effect Sound
Theory of relativity (Einstein) Modern Physics
Faraday's law of induction Electromagnetism
Gauss's law Mathematical Physics
Pascal's law Fluid statics and dynamics
Planck's law Electromagnetism
Raman scattering Optics
Vlasov equation Plasma physics

Nobel Prize In Physics


  • The Nobel Prize in Physics is the most prestigious award given yearly by the Royal Swedish Academy of Sciences.

  • The Noble prize is given to those physicists who conferred the most outstanding contributions for mankind (in physics).

  • Wilhelm Röntgen, a German/Dutch physicist, was the first person who had received the first Nobel Prize in 1901.

  • Wilhelm Röntgen had received the Nobel Prize for discovery of the remarkable x-rays).

  • In the field of physics (by the time), only two women have won the Nobel Prize, namely Marie Curie (in 1903) and Maria Goeppert Mayer (in 1963).

  • The following table illustrates some of the significant physicists who have received the Nobel Prize along with their remarkable works −

Name Year: Country Work
Wilhelm Conrad Röntgen 1901: Germany Discovery of the remarkable rays
Hendrik Lorentz 1902: Netherlands Worked on the influence of magnetism upon radiation phenomena
Pieter Zeeman
Antoine Henri Becquerel 1903: France Spontaneous radioactivity
Pierre Curie Radiation phenomena
Maria Skłodowska-Curie 1903: Poland/France
Philipp Eduard Anton von Lenard 1905: Austria-Hungary Worked on cathode rays
Guglielmo Marconi 1909: Italy Development of wireless telegraphy
Karl Ferdinand Braun 1909: Germany
Max Planck 1918: Germany Discovered energy quanta
Johannes Stark 1919: Germany Discovered Doppler effect in canal rays
Albert Einstein 1921: Germany-Switzerland For the discovery of the law of the photoelectric effect
Niels Bohr 1922: Denmark Investigated the structure of atoms
Chandrasekhara Venkata Raman 1930: India Worked on scattering of light
Werner Heisenberg 1932: Germany Created quantum mechanics
Erwin Schrödinger 1933: Austria Discovered productive forms of atomic theory
Paul Dirac 1933: United Kingdom
James Chadwick 1935: UK Discovered Neutron
Victor Francis Hess 1936: Austria Discovered cosmic radiation
Willis Eugene Lamb 1955: US Discovered the fine structure of the hydrogen spectrum
Emilio Gino Segrè 1959: Italy Discovered the antiproton
Owen Chamberlain 1959: US
Lev Davidovich Landau 1962: Soviet Union Theories for condensed matter
Maria Goeppert-Mayer 1963: US Discovered nuclear shell structure
J. Hans D. Jensen 1963: Germany
Hans Albrecht Bethe 1967: US Worked on the theory of nuclear reactions
Murray Gell-Mann 1969: US Classification of elementary particles and their interaction
Hannes Olof Gösta Alfvén 1970: Sweden Worked on plasma physics
Louis Néel 1970: France Worked solid state physics (antiferromagnetism and ferrimagnetism)
Dennis Gabor 1971: Hungary-UK Developed the holographic method
John Bardeen 1972: US Developed the theory of superconductivity
Leon Neil Cooper
John Robert Schrieffer
Arno Allan Penzias 1978: US Discovered cosmic microwave background radiation
Robert Woodrow Wilson
Nicolaas Bloembergen 1981: Netherlands-US Developed laser spectroscopy
Arthur Leonard Schawlow 1981: US
Ernst Ruska 1986: Germany Designed the first electron microscope
Johannes Georg Bednorz 1987: Germany Discovered the superconductivity in ceramic materials
Karl Alexander Müller 1987: Switzerland
Robert B. Laughlin 1998: US Discovered a new form of quantum fluid
Horst Ludwig Störmer 1998: Germany
Daniel Chee Tsui 1998: China-US
Jack St. Clair Kilby 2000: US Developed integrated circuit
Riccardo Giacconi 2002: Italy-US Discovered cosmic X-ray sources
Roy J. Glauber 2005: US Worked on the quantum theory of optical coherence
Willard S. Boyle 2009: Canada-US Invented an imaging semiconductor circuit – the CCD sensor
George E. Smith 2009: US
Takaaki Kajita 2015: Japan Discovered neutrino oscillations, which illustrations that the neutrinos have mass
Arthur B. McDonald 2015: Canada

Awards Given in Physics

Following are the exclusive category of awards given in the field of Physics −

David Adler Lectureship Award in the Field of Materials Physics
Alexander Hollaender Award in Biophysics
Hannes Alfvén Prize
Andrew Gemant Award
Appleton Medal and Prize
ASA Gold Medal
ASA Silver Medal
Hans Bethe Prize
Blaise Pascal Chair
Bogolyubov Prize
Bogolyubov Prize (NASU)
Bogolyubov Prize for young scientists
Boltzmann Medal
Ludwig Boltzmann Prize
Tom W. Bonner Prize in Nuclear Physics
Max Born Prize
Breakthrough Prize in Fundamental Physics
Oliver E. Buckley Condensed Matter Prize
CAP-CRM Prize in Theoretical and Mathematical Physics
Charles Hard Townes Award
Comstock Prize in Physics
Elliott Cresson Medal
Davisson–Germer Prize in Atomic or Surface Physics
Demidov Prize
Duddell Medal and Prize
Eddington Medal
Edison Volta Prize
Einstein Prize for Laser Science
Albert Einstein Award
Albert Einstein Medal
Einstein Prize (APS)
Albert Einstein World Award of Science
EPS Europhysics Prize
Faraday Medal and Prize
Nobel Prize in Physics
Fluid Dynamics Prize (APS)
Foresight Institute Feynman Prize in Nanotechnology
List of Fritz London Memorial Prizes
Hector Memorial Medal
Dannie Heineman Prize for Astrophysics
Dannie Heineman Prize for Mathematical Physics
Henri Poincaré Prize
Hoyle Medal and Prize
Infosys Prize
Isaac Newton Medal
Frank Isakson Prize for Optical Effects in Solids
James Clerk Maxwell Prize in Plasma Physics
James C. McGroddy Prize for New Materials
Niels Bohr Institute
Om Prakash Bhasin Award
Otto Hahn Prize
Abraham Pais Prize for History of Physics
George E. Pake Prize
Max Planck Medal
Earle K. Plyler Prize for Molecular Spectroscopy
Pomeranchuk Prize
Prize Ampère
Aneesur Rahman Prize for Computational Physics
Rayleigh Medal
Rayleigh Medal and Prize
David Richardson Medal
Richtmyer Memorial Award
Robert A. Millikan award
Rumford Prize
Rutherford Medal and Prize
Sakurai Prize
Abdus Salam Award
Arthur L. Schawlow Prize in Laser Science
Walter Schottky Prize
Simon Memorial Prize
Sloan Fellowship
R W B Stephens Medal
Swan Medal and Prize
Thomson Medal and Prize
Three Physicists Prize
VASVIK Industrial Research Award
Wolf Prize in Physics

Scientific Units Named After Inventors

The following table illustrates the list of scientific units, which are exclusively named after their inventors/discovers −

Scientist/Inventor Unit Measures
André-Marie Ampère ampere (A) Electric current
Lord Kelvin kelvin (K) Thermodynamic temperature
Antoine Henri Becquerel becquerel (Bq) Radioactivity
Anders Celsius degree Celsius (°C) Temperature
Charles-Augustin de Coulomb coulomb (C) Electric charge
Alexander Graham Bell decibel (dB) Ratio
Michael Faraday farad (F) Capacitance
Joseph Henry henry (H) Inductance
Heinrich Rudolf Hertz hertz (Hz) Frequency
James Prescott Joule joule (J) Energy, work, heat
Sir Isaac Newton newton (N) Force
Georg Simon Ohm ohm (Ω) Electrical resistance
Blaise Pascal pascal (Pa) Pressure
Werner von Siemens siemens (S) Electrical conductance
Nikola Tesla tesla (T) Magnetic flux density
Alessandro Volta volt (V) Electric potential & electromotive force
James Watt watt (W) Power & radiant flux
Wilhelm Eduard Weber weber (Wb) magnetic flux
Jean-Baptiste Biot biot (Bi) Electric current
Peter Debye debye (D) Electric dipole moment
Loránd Eötvös eotvos (E) Gravitational gradient
Galileo Galilei galileo (Gal) Acceleration
Carl Friedrich Gauss gauss (G or Gs) Magnetic flux density
William Gilbert gilbert (Gb) Magnetomotive force
James Clerk Maxwell maxwell (Mx) Magnetic flux
Hans Christian Ørsted oersted (Oe) Magnetic field strength
Jean Léonard Marie Poiseuille poise (P) Dynamic viscosity
George Gabriel Stokes stokes (S or St) Kinematic viscosity
Anders Jonas Ångström ångström (Å) Distance
Heinrich Barkhausen Bark scale Psychoacoustical scale
Thomas Hunt Morgan centimorgan (cM) Recombination frequency
Marie Curie and Pierre Curie curie (Ci) Radioactivity
John Dalton dalton (Da) Atomic mass
Henry Darcy darcy (D) Permeability
Gordon Dobson Dobson unit (DU) Atmospheric ozone
Daniel Gabriel Fahrenheit degree Fahrenheit (°F) Temperature
Enrico Fermi fermi (fm) Distance
Godfrey Newbold Hounsfield Hounsfield scale Radio density
Karl Jansky jansky (Jy) Electromagnetic flux
Samuel Pierpont Langley langley (ly) Solar radiation
Irving Langmuir langmuir (L) Gas exposure dose
Wilhelm Röntgen röntgen (R) X-rays or gamma radiation
Charles Francis Richter Richter magnitude Earthquake
Theodor Svedberg svedberg (S or Sv) Sedimentation rate
Evangelista Torricelli torr (Torr) Pressure

Physics - Top Institutes

Following are the worldly recognized top institutions in the field of Physics −

Institute Country
Massachusetts Institute of Technology (MIT) USA
Harvard University USA
University of Cambridge UK
Stanford University USA
Yale University USA
University of California, Berkeley (UCB) USA
University of Oxford UK
Columbia University USA
Princeton University USA
California Institute of Technology (Caltech) USA
University of Chicago USA
University of Michigan USA
ETH Zurich - Swiss Federal Institute of Technology Switzerland
Ludwig-Maximilians-Universität München Germany
Technical University of Munich Germany
University of Toronto Canada
New York University (NYU) USA
Imperial College London UK
University of Pennsylvania USA
Boston University USA
The University of Edinburgh UK
The University of Tokyo Japan
Cornell University USA
University of Maryland, College Park USA
Sapienza University of Rome Italy
University of Texas at Austin USA
National University of Singapore (NUS) Singapore
RWTH Aachen University Germany
Seoul National University South Korea
University College London UK
Georgia Institute of Technology USA
Peking University China
Osaka University Japan
Pennsylvania State University USA
The University of Melbourne Australia
University of California, San Diego (UCSD) USA
University of British Columbia Canada
McGill University Canada
National Taiwan University (NTU) Taiwan
The Australian National University Australia
Brown University USA
Duke University USA
Delft University of Technology Netherlands
Durham University UK
Humboldt-Universität zu Berlin Germany
Johns Hopkins University USA
Lund University Sweden
Nagoya University Japan
Northwestern University USA
The Ohio State University USA
Purdue University USA
Rice University USA
Rutgers University - New Brunswick USA
Stockholm University Sweden
Technische Universität Dresden Germany
University of Bristol UK
University of Washington USA