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Curiosity Curiosity Curiosity helps determine whether Mars could ever have supported life, as well as determining the role of water, and to study the climate and geology of Mars.
The world around you!

Look at the world around you: Landing of Quest on Mars; Experiments in Particle Accelerators; Use of MRI to Probe Body; Immersive 3D TVs; Neon-lit Downtowns; Electricity from Nuclear and Thermal Power Stations; High-speed Magnetic Levitating Trains; Flight of Stealth Bombers; Communication using Smart Phones, Tablets, and Laptops; Automobiles with Voice Activated Controls; Wireless Music Systems; and Fun on Skateboards.

The above are just a tiny snapshot of objects and events possible with the help of Physics. Each object or event from the list would not operate but for Physics: the most fundamental of sciences. In fact, a good question to consider is - would there be an everyday life like we have now, but for Physics?

Explore physics Space exploration through Einstein's equation Even the radiation pressure that propels spacecraft to study our distant universe is made possible by Einstein's E=mc2.
Explore more through physics

How did the universe come about? What is its structure like? What are the basic particles that go into the making of it? And what principles govern its operation? These big questions are worth your attention. In an effort to figure the universal order, you will also come to know the processes that have shaped planet earth.

Your exploration of the physical world around you will unravel a simple idea: all natural objects, events, and processes are interconnected in such a way that only a few concepts are needed to make sense of it all. Our endeavor is to help you get a grip of the key concepts, theories, and principles so that you know and apply the workings of nature.

The study of physics is fascinating. Trying to get a clear picture of the concepts, theories, and principles is critical, now, more than ever. Do look deep and get a clear picture of the universal order – you stand to succeed now, and in the future.

physical phenomena Examples of physical phenomena Different phenomena as seen in our daily life helps us to ask the questions and seek answers as to why the things are the way they are.
Explains why things are the way they are..

Albert Einstein said in 1936: "The eternal mystery of the world is its comprehensibility". Universe is easily understood as it is governed by a small set of very simple rules – be it the rise of water when one steps into it; or the dropping of light/heavy objects from a tower; or seeing an apple hit the ground and not fly upwards from a tree. Physicists try to find patterns and principles that describe why the physical world behaves the way it does. Physics is the most fundamental of the sciences as it deals most directly with the simple rules that govern the universe and the simple particles that everything in the universe is made of.

We experience many interesting phenomena in the world around us – colours of a rainbow, the flight of birds, ice floating on water, lightning and the thunder that follows it in a storm, the beautiful hexagonal symmetry of small snowflakes and many more. These can be explained with the understanding of physical principles and processes that cause the phenomena we observe in daily life. The observation and exploration of the world around us helps us in identifying the underlying order or pattern in what we find. Physics is that part of science which deals primarily with the inanimate world, trying to identify the most fundamental and unifying principles. The phenomena of nature are roughly divided into classes like mechanics, acoustics, heat, electricity, magnetism, light, quantum mechanics and nuclear physics.

Discovery of the electron Discovery of the electron The discovery of the electron by Thomson Joseph J. Thomson (1856-1940) built on the work of Hertz, whose experiments showed that cathode rays were not particles. Thomson realised that the fault was with Hertz's equipment, so made a cathode ray tube with a better vacuum. Thomson was thus able to show that the cathode beam was deflected by electric and magnetic fields. In a series of classic experiments, Thomson showed electrons to be particles, publishing his results in 1897. Thomson won the 1906 Nobel Prize for Physics. His son, George, won the 1937 Prize for demonstrating the electron's wave-particle nature.
Nature of Physics: A journey from Macro to Micro..

We gain some insight into the nature of physics by exploring the story of physics from its beginnings until now, relating our knowledge of phenomena to general principles and using these established principles to explore an ever expanding list of applications. The progress of physics depends on a continuing interaction between experiment and theory. Weighing balance is the most common example for application of simple principle of 'Lever' discovered by Aristotle. The process of arriving at general principles to describe how the nature behaves continues to find limitations in the range of validity of the theories.

The journey in Physics is all the more exciting as no theory is taken to be final. New observations or evidence inconsistent with known theory can force original theory to be revised or discarded. For example, Ptolemy believed earth to be the center of universe until Copernicus proved it otherwise. Building on the Copernican idea of earth's revolution around the sun, Johannes Kepler proceeded to formulate the laws regarding planetary motions. In addition, Kepler also stated that the planetary orbits are elliptical rather than circles – a fact still accepted.

Leaning Tower of Pisa Leaning Tower of Pisa Galileo suggested that the acceleration of a falling body is independent of its weight.
Important discoveries

The new findings help physicists to modify the existing theories or propose new theories to explain new observations. Galileo suggested that the acceleration of a falling body is independent of its weight after his experiments by dropping objects from the Leaning Tower of Pisa. However it is valid only if the force exerted by air on the falling objects is much less than the weight. A feather and a cannon ball do not fall at the same rate as force exerted by air on feather due to buoyancy and air resistance is significant in comparison with its weight. Theories about nature of light have been debated for long before concluding the particle-wave duality of light and the subatomic particles like electrons. Every physical theory has a range of validity just as laws of classical mechanics are not applicable at atomic and subatomic levels.

Solar system Solar system Systems' length scales are greater than atomic scale and motions are much slower than the speed of light.
Macro Physics

In general, it is found that classical physics (mechanics, optics, acoustics, thermodynamics, and electromagnetism) works at the macroscopic (above atomic) level where: space and time are contexts in which all the physical phenomenon take place; space and time are considered absolute and that no physical phenomena can affect them; systems' length scales are greater than atomic scale and motions are much slower than the speed of light; and mechanics, electricity, and magnetism embody a continuous wave model of light.

Model of an atom Model of an atom An atom consists of protons, neutrons in the center (nucleus) and electrons which revolve around the nucleus.
Micro Physics

Not stopping at the laws of classical physics, pioneers between late 19th and very early 20th century probed further. The results: X-rays by Wilhelm Roentgen, properties of electron by JJ Thomson, radioactivity by Marie and Pierre Curie, model of an atom by Ernest Rutherford, and the Michelson-Morley experiments.

These discoveries and studies, in turn, acted as the gateway to explore the natural phenomena at a microscopic (atomic) or sub-microscopic level.

Modern Physics Filling of atomic orbitals using Aufbau rule
  • s orbitals have 1 possible value of m to hold 2 electrons
  • p orbitals have 3 possible values of m to hold 6 electrons
  • d orbitals have 5 possible values of m to hold 10 electrons
  • f orbitals have 7 possible values of m to hold 14 electrons
Atomic theory

Extending human observations of natural phenomena further, the great minds of 20th century studied the nature and behavior of matter and energy at a very small scale. It was Rutherford who proposed that mass of an atom was concentrated in the nucleus and that the nucleus has a positive charge. He also added that the nucleus was surrounded by negatively charged electrons. Extending this model, Neils Bohr placed the electrons in a definite shell, or quantum shells. These observations led to new insights into the arrangement of electrons around nucleus and the processes by which the arrangements change. The field of atomic theory was born.

The discovery of neutron by James Chadwick, on the other hand, led to a new field called nuclear theory. This theory proposed a new type of force called nuclear force. Physicists soon had four fundamental forces in nature to contend with: strong nuclear force, weak nuclear force, gravitation, and electromagnetism. Now, the attention of physicists turned deeper into the structure of nucleons, it was Murray Gell-Mann who proposed that nucleons were composed of quarks. The deeper physicists travelled, they observed that a different picture of space, time, and matter presented itself (as compared to the classical physics). These phenomena are now well explained by advancements, in what is termed, the modern physics.

Modern physics Neutron discovery In 1930 it was discovered that Beryllium, when bombarded by alpha particles, emitted a very energetic stream of radiation. This stream was originally thought to be gamma radiation. However, further investigations into the properties of the radiation revealed contradictory results. Like gamma rays, these rays were extremely penetrating and neutral since they were not deflected upon passing through a magnetic field. However, unlike gamma rays, these rays did not discharge charged electroscopes (the photoelectric effect). Irene Curie and her husband discovered that when a beam of this radiation hit a substance rich in protons. For example paraffin protons were knocked loose which could be easily detected by a Geiger counter.
Important contributions to Modern Physics

Modern physics draws from two theories: Einstein's Theory of relativity and Quantum Mechanics.
Theory of relativity states that: measurements of time and space are affected by motion between observer and what is being observed; speed of light in free space is constant and a physical boundary for motion; equivalence of mass and energy; and curvature of space-time describing the gravitational effect at every point in space.

Mean while, Quantum theory affirms: energy is radiated and absorbed in discrete "quanta"; physical quantities can change in only discrete (quanta) amounts and not in a continuous (wave-like) way; light waves act as particles and particles act like waves; more precise the position of some particle is determined, less precisely its momentum can be known and vice-versa; measuring quantum state of one particle also places constraints on the measurement of other particles.

The outcome of quantum and relativity theories has forced a re-think on the nature of physics. While classical physics depended on cause-and-effect relationship to explain phenomena, modern theories describe the physical phenomena as the result of fundamentally mathematical, indeterministic processes.

Physicists are now more inclined to say that if A occurs, there is an 'X percent' chance that B will follow. Determinism (cause-effect) in physics has been replaced by probability.

Stepping back, taking it all in, it should be evident (seen to the unseen world) that the endeavor is to find the few unifying principles that govern the behavior of nature. It is in the nature of Physics.

Newton's Laws Newton's laws The laws which guide the motion of objects that lead to study of branch of Physics known as Mechanics.
Classical mechanics: The start of Physics

Physics started with mechanics – the science of machines, forces and motion. Newton described gravity as glue that held everything together; a force of attraction that was felt mutually by all particles everywhere in the universe. The force of attraction is very strong between the earth and massive objects close to it and it is very weak between earth and tiny objects which are far away. The force of attraction between two objects depended on the distance between their centers, their two masses and some constant which is called Newton's gravitational constant.

The first great flowering of physics came in when Newton refined Galileo's seminal work with metal balls, by studying how objects moved in response to any force, not just gravity. Newton summarized their behavior in three simple laws.

The first law says that in a world where there are no forces to push things around, an object that is not moving will remain at rest forever, where as an object that is moving will keep moving forever along a straight line and at a constant speed. According to second law, an object pushed by a force, either accelerate or decelerate depending on how the force is applied.

Newton's second law of motion was an example of cause-and-effect relationship that we seek to recognize in the phenomena we observe.

The third law says that if two objects collide with each other, each will feel the force of collision equally but in opposite directions.

Electromagnetic Spectrum and Electromagnetic Wave Electromagnetic spectrum and Electromagnetic wave Electromagnetic spectrum is the range of all possible frequencies of the electromagnetic radiation. In an electromagnetic wave, the magnetic and the electric fields are perpendicular to each other.

Nothing is at rest in this Universe as everything is moving – stars, planets, moons, earth and everything on earth's surface - matter and energy in the in the form of molecules, atoms and sub atomic particles such as electrons, protons, photons and quarks.

The pattern of motion can be best described in terms of vibrations and waves to understand the nature of light, sound and electromagnetic waves. Wavelength which is a measure of the distance between peaks of the disturbance influence how a wave interacts with matter such as transmission, absorption, reflection, diffraction and interference.

The interaction of electromagnetic waves with matter depends on the wavelength and they are grouped with distinctive names like radio waves, microwaves, infrared waves, visible light, ultraviolet, X-rays and gamma rays depending on the wave length. Even the different wavelengths of visible light interact differently giving us the perception of colour. The sky appears blue as the atmosphere scatters short wavelength light much more than long wavelength light.

Producing Electricity Producing electricity throw using Magnetism
  • In 1831, an English scientist, Michael Faraday discovered that magnetism could produce electricity. He wrapped two insulated coils of wire, forming helices, around a massive iron ring. One helix was connected to a battery and the other to a galvanometer. Faraday believed that when a current flowed through one helix the magnetic field it created would be channelled to the other helix by means of a permeable iron ring.
  • Electromagnetic induction is the complementary phenomenon to electromagnetism. Instead of producing a magnetic field from electricity, we produce electricity from a magnetic field. There is one important difference, though: whereas electromagnetism produces a steady magnetic field from a steady electric current, electromagnetic induction requires motion between the magnet and the coil to produce a voltage.
Energy transformations

The knowledge of the physical world later expanded to include such areas as heat, sound, electricity and magnetism, followed by the idea of conservation of energy. Energy exists in many forms, such as heat, light, chemical energy, and electrical energy. Thermodynamics is the study of energy and the laws of thermodynamics govern the energy transformations. The First Law of Thermodynamics (conservation) states that energy is always conserved, it cannot be created or destroyed. In essence, energy can be converted from one form into another. The contribution of Rudolf Clausius is immense through his famous second law of thermodynamics which states that in any closed system, the entropy of the system will either remain constant or increase. The most efficient heat engine cycle is the Carnot cycle, consisting of two isothermal processes and two adiabatic processes and the second law of thermodynamics sets the limiting value on the efficiency of Carnot cycle.

Michael Faraday discovered the connections between the phenomena of electricity and magnetism by observing that the flow of electric charge through a wire caused magnetic effects, and a changing magnetic field could produce a current in a closed loop of wire. He summarized his historic discovery in a single statement: "Whenever a magnetic force increases or decreases, it produces electricity; the faster it increases or decreases, the more electricity it produces". Amount of electricity produced by magnetism was equal to the rate of increase or decrease of the magnetic force. It was said that Faraday has seen the world through the eyes of poet by seeing simplicity while there is complexity. And then, toward the end of the century, the great physicist James Clerk Maxwell showed how, by uniting the equations that described electric and magnetic fields, he could account for the transmission of light through space at the amazing speed of about 3 × 108 meters per second, a value that was already known from experiment. The net result was a tremendous unification of physics. The Faraday's law is very significant as it changed the world leading to development of electric motors, generators and everything that works on electricity.

X - ray Diffractometer X-ray Diffractometer This instrument helps in determining the arrangement of atoms and molecules of a crystal known as Crystallography.
Modern Physics

As the 19th century approached its end, the physicists of the time felt that physics was almost a completed subject. Its primary ingredients were absolute space and time, the causal laws of mechanics, electricity and magnetism, embodying a wave model of light, and a picture of matter as consisting of discrete and indivisible particles obeying these laws. But such complacency was shattered in less than ten years by the discovery of the electron, radioactivity, the quantum of energy and special relativity as each of them, in its own way, called for a drastic revision of our picture of the physical world. The discovery of X-rays, which are electromagnetic waves, like light but of a much shorter wavelength had a great influence on the course of physics. J J Thomson's discovery of electron, negatively charged particle with a far smaller mass than any particle previously known, changed the old idea forever that atoms are indivisible. The other constituents that went into the structure of atoms, namely protons and neutrons were discovered later.

Electron diffraction pattern Electron diffraction pattern Demonstration of wave-particle duality. An electron gun has been fired at a thin sheet of graphite. The electrons passed through and hit a luminescent screen, producing the patterns of rings associated with diffraction. Diffraction occurs when a wave passes through an aperture similar in size to its wavelength. But electrons are particles, so should not exhibit the same phenomenon unless they can also behave like waves. De Broglie (1892 - 1987) correctly deduced that this was the case and that particles have wavelengths inversely proportional to their momentum.
Wave-particle duality

Radiant heat from hot objects was considered a form of electromagnetic radiation, but classical theory of electromagnetic radiation could not explain this spectrum. The German physicist Max Planck (1858 - 1947) suggested that energy from a hot body could only be released in discrete amounts, proportional to the frequency (inversely proportional to the wavelength) of the emitted radiation, according to the formula E = hf ( where 'f' is the frequency and 'h' is what quickly came to be known as Planck's constant). Thus the quantum was born. Planck stopped short of proposing that the radiation itself was quantized as the classical wave theory of light still stood supreme.

The discoveries in atomic physics and radiation were enough to shake classical physics to its core, but more was to come. In 1905, Einstein came forward with his revolutionary proposal that neither time nor space was absolute, that they were related to one another, and that both depended on measurements made with respect to a chosen frame of reference, which had to be identified. This special theory of relativity was particularly troubling to the traditionalists who assumed that a hypothetical medium is essential as the carrier of light and all other kinds of electromagnetic waves. Physicists had to get used to the idea that electromagnetic waves did not need a medium to wave in.

Photo Electric Effect Photo-electric effect The photoelectric effect was first observed in 1887 by Heinrich Hertz (1857-1894) during experiments with a spark-gap generator — the earliest form of radio receiver. Under the right circumstances light can be used to push electrons, freeing them from the surface of a solid. This process is called the photoelectric effect. A material that can exhibit this phenomena is said to be photoemissive, and the ejected electrons are called photoelectrons.
Compton effect and Photo-electric effect

Building on the Rutherford model of atom, Niels Bohr proposed a model of atom where electrons orbit around a positively charged nucleus and by applying Planck's idea of quantization, the orbits were limited to a discrete set of radii. It is an interesting fact that Bohr like Planck before him, did not believe that the light itself was quantized, until he was finally convinced, many years later, by direct experimental evidence of collisions between light quanta and electrons which is called the Compton effect.

People's ideas about the nature of light oscillated between a particle model and a wave model. Photo electric effect and the ejection of electrons from metals by light were consistent with Einstein's proposal that the energy of light was emitted and absorbed in minute packets, called quanta were named as photons. In other words, light had properties that embraced those of both particles and waves which was a totally new idea.

The modern theory of quantum mechanics of luminous radiation accepts the fact that light seems to have a dual nature. Holograms are the best creations of this dual nature.
Quantum theory

Louis de Broglie (1892 - 1987) went one step further, and made the complementary suggestion that electrons, which had been unequivocally accepted as particles, might have wave like properties, with a wavelength equal to h/p, where 'h' is Planck's constant and 'p' is the momentum. Electrons of a specific energy were diffracted by crystal lattices in just the same way as X-rays. The accepted categorization of the basic elements of the physical world ceased to apply at the atomic level and it was necessary to accept a photon or an electron simply for what it was, defined by its behavior. It was discovered very soon that every kind of physical object that had been labelled as a particle( neutrons, protons and every kind of neutral atom or molecule) also had this wave property, with a wavelength given by de Broglie's formula.

Wave Pattern Wave properties of an atom Quantum mechanics recognized that at the atomic scale, electrons were controlled by their wave properties, and those wave properties were in turn defined mathematically by the wavefunction, Ψ, of the electron.
Randomness of quantum particles

The randomness of radioactivity and the wave/particle duality could simply not be fitted into the framework of classical physics. Yet it was clear that the classical picture worked very well for many purposes. The answer was soon provided by two brilliant theorists, Werner Heisenberg and Erwin Schrödinger who created the new science of quantum mechanics. Schrödinger constructed an equation and defined a wave function that led to the solution of a vast range of atomic problems. There were strong similarities to acoustics. We know that, in the open air, sound of any wavelength or frequency can be transmitted, but in an enclosed space, such as the interior of a room or the body of a wind instrument, only certain wavelengths and frequencies are possible. Similarly, in empty space electrons of any wavelength are possible, but the interior of an atom is like an enclosure, with rather soft walls defined by the attraction of the positive nucleus for the electrons. Electrons of less than certain energy cannot escape, and such electrons are restricted to certain discrete energies.

The wave and particle aspects of photons are complementary. Photons are detected as particles, at a particular point, but their motion from source to detector is described by a wave equation. Max Born proposed that Schrödinger's waves are waves of probability. Phenomena such as radioactivity and the double slit interference experiment show that individual events on the atomic scale can have a random property. Quantum phenomena have forced us to recognize that all kinds of individual events are not subject to strict causal laws, but the statistical behavior of large populations of identical atomic systems is rigorously predictable.

Interference Pattern Interference pattern The diffraction and interference effects appear at first sight to be due to the beam of electrons, interfering with each other. However, the interference pattern still results even if only one electron traverses the apparatus at a time. In this case, the pattern is built up gradually from the statistically correlated impacts on many electrons arriving independently at the detection system.
Events at Atomic level

It continued to be an article of faith among most physicists that the laws of strict cause-and-effect allow us to predict, in principle, the course of all events above the atomic level.

The great French physicist Pierre Simon de Laplace articulated this belief in a famous statement: "An intelligence which, at a certain instant, knew all the forces of nature and also the situations [positions and velocities] of the entities in it, and which furthermore was capable of analyzing all these data, could encompass in the same formula the motions of the largest bodies in the universe and those of the lightest atom; to it [this intelligence] nothing would be uncertain, and the future would be as clear to it as the past."

Nuclear Force Nuclear force The nuclear force (or nucleon–nucleon interaction or residual strong force) is the force between two or more nucleons. It is responsible for binding of protons and neutrons into atomic nuclei. The energy released causes the masses of nuclei to be less than the total mass of the protons and neutrons which form them. This is the energy used in nuclear power and nuclear weapons. The nuclear force is due to a strong force that binds quarks together to form neutrons and protons.
Nuclear theory

The discovery of neutron by James Chadwick in 1932 led to a new field of nuclear theory which proposed a new type of force called nuclear force. Nuclear forces are of extremely short range as their effect scarcely extends beyond the boundary of an atomic nucleus and so plays no role at all in the interaction between different atoms. There are two types of nuclear forces, labelled simply as strong and weak. The strong force is what holds the protons and neutrons in a nucleus together against the electrical repulsion of the protons. The weak force is the agent behind some forms of radioactive decay. The attention of many physicists turned to the internal structure of the nucleons. The experiments to probe the nature of nucleons required construction of bigger and bigger particle accelerators, acting as sources of more and more energetic particles. Murray Gell Mann proposed that nucleons were composed of triads of quarks.

The first calculations in quantum mechanics had been of the energy states of electrons in individual atoms and the next step was to consider how those energy states would be changed as similar atoms were brought more and more closely together. The behavior of electrons when the atoms are brought close enough affects the properties of the matter like conductivity - classifying them as good conductors, insulators and semiconductors.

Lasers and Astronomy Astronomy and Lasers The laws of physics are applied in the field of astronomy and in studying lasers.
Semiconductors and LASERs

The properties were controllable through the addition of other types of atoms called doping in semiconductors which led to the invention of the transistor. Then the whole science of solid state electronics evolved, which now dominates our communications and computer technology. Einstein proposed that the transition of an atom from its excited state to its lower state would be enhanced if it were struck by a photon of the same energy and it would lead to the appearance of two quanta of a certain energy where there had only been one before. This can lead to chain reaction stimulated by photons striking a large population of atoms in the excited state, giving rise to a big burst of radiation of the same frequency and wavelength. Based on this principle, LASER (which stands for Light Amplification by Stimulated Emission of Radiation), a beam of light of very high intensity and very small angular divergence was invented by Theodore Maiman in 1927.

Collapsed bridge Damage due to resonance The Broughton Suspension Bridge that spanned the River Irwell in the UK collapsed due to a mechanical resonance induced by troops marching over the bridge in step (that’s why soldiers break step when marching across a bridge).
Similarities in Physics : Finding patterns

If tracing the history of physics takes your breath away, imagine knowing its deep concepts, theories, and principles! Once you get a clear grip on the key concepts, you will see how they appear and re-appear in different situations. You will notice how different concepts come together to help you understand a phenomena. In other words, you will see a pattern to the concepts that help you appreciate the nature of physics. The most interesting part is to find similarities in basic laws underlying all these seemingly different phenomena. A comprehensive view of nature will help us in dealing with new ideas and solving problems in real life situations.

Let's take, Boltzmann's constant, for instance. A simple combination of symbols kT, where 'k' is Boltzmann's constant and ' T' is an absolute temperature finds application in study of diverse topics such as gas laws, kinetic theory, diffusion, chemical processes, noise, thermal and electrical conduction.

Dispersion Dispersion The water droplets present in air cause dispersion of white light in to its seven constituent colours.
Core concepts of Physics

Boltzmann's constant defines the relation between absolute temperature and kinetic energy contained in each molecule of an ideal gas. It must be noted that equation relates energy at an individual particle level and temperature (observed at collective or bulk level). The Boltzmann constant, k, is a bridge between macroscopic and microscopic physics. Once you approach Boltzmann constant as a concept to understand, rather than an equation to know, you will see the beauty of physics at work. All it takes for you is to master the core concepts and principles.

Consider the features of waves as they propagate such as reflection, resonance, dispersion and interference. All waves behave the same way, whether they may be the waves of transverse displacement travelling along a stretched string, waves of electric voltage travelling along a transmission line, sound waves travelling through air, waves of electromagnetic field travelling through space or water waves travelling along the surface of ocean.

Universe Universe and the dark energy Physicists believe that only 4 percent of the universe is made up of ordinary matter like stars and planets, with the remaining 96 percent composed of dark matter and dark energy.
Connecting concepts

Fourier' heat flow equation that explains the relation between quantity of heat flow and the temperature difference, Ohm's law which describes the steady flow of electric charge in a wire, Poiseuille's equation governing fluid flow being proportional to the pressure difference are all analogies of the generalized steady flow of different entities namely heat, charge and fluid.

You can see that the volume of liquid has a correspondence with the amount of electric charge and the quantity of heat and that the pressure difference causing the flow of liquid is like the potential difference causing an electric current and the temperature difference causing a flow of heat.

Applications Semiconductor and Nuclear reactions
  • Semiconductor materials are useful because their behavior can be manipulated by the addition of impurities, known as doping.
  • The actual reaction involves a deuterium nucleus fusing with a tritium nucleus to form an alpha particle (4He nucleus) and a neutron.

Scientists of all disciplines make use of the ideas of physics including chemists and biologists. The space travel, mobile computing and 3D experience were made possible with application of principles or laws of physics in engineering and technology. Semiconductors which led to the invention of the transistor, and then the whole science of solid state electronics, now dominate our communications and computer technology. Lasers find many applications in spectroscopy, industry, medical and defensive countermeasures. It would be a great break through for clean energy if we can create plasma of certain light elements such as hydrogen isotopes and make the system hot enough to produce nuclear fusion reactions.

Even though chemistry is now being explained in terms of electromagnetic forces and quantum theory and biology is beginning to derive valuable insights from the application of basic physical principles, physics is primarily concerned with understanding the universe, its constituent particles and their interactions at the most primitive level. Observe nature through eyes of physics, grasp the laws of nature, identify similarities and develop insight to be able to apply what you have learnt in finding solutions to challenges in making the world a better place to live.

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