Physics encompasses a broad spectrum of concepts and mathematical expressions. Furthermore, the entirety of our understanding of the physical realm may be succinctly encapsulated by five ideas, which are undeniably deserving of the title "The Great Theories of Physics." Every theory is a structured system of concepts and mathematical expressions that have undergone experimentation and validation. The scientific community consistently verifies these hypotheses.
Key Theories in Physics
Mechanics
Mechanics is a scientific field that deals with the movement of objects when forces are applied to them, including situations where an object remains stationary.
The primary focus in the study of motion is the interaction of forces between objects. Consequently, the investigation encompasses subjects like as gravity, electricity, and magnetism, depending on the specific forces at play. The study of mechanics involves analyzing how bodies move in response to applied forces.
Mechanics may be categorized into three branches:
- Statics focuses on forces acting on a stationary body.
- Kinematics defines the potential movements of a body or group of bodies.
- Kinetics aims to understand or forecast the motion that will happen in a certain scenario.
Alternatively, mechanics might be categorized based on the specific system being investigated. The most basic mechanical system is the particle, which refers to a body that is so tiny that its shape and internal structure do not matter in the specific problem being considered. The motion of a system consisting of two or more particles, which interact with each other through forces and may also experience external forces, is more intricate.
Classical mechanics is concerned with the movement of objects in response to forces or the state of balance in objects when all forces are equal.
The subject can be understood as the expansion and implementation of fundamental principles initially stated by Isaac Newton in his work Philosophiae Naturalis Principia Mathematica (1687), generally referred to as the Principia.
Looking for physics help? Find a physics teacher in Kolkata or wherever you are when you search on Superprof!
Sir Isaac Newton
The following are Newton's laws of motion, which are referred to as postulates. They may be utilized to accurately forecast a broad range of events, spanning from the movement of small particles to the interactions of intricate systems. This page discusses a range of these uses.
Within the context of contemporary physics, classical mechanics may be regarded as an approximation that emerges from the deeper principles of quantum mechanics and the theory of relativity. Nevertheless, this perspective on the subject's position significantly underestimates its significance in shaping the framework, terminology, and instinct of contemporary science and scientists. The contemporary perspective of the world and humanity's position within it is strongly based on classical mechanics. Furthermore, some concepts and findings from classical mechanics persist and hold significant significance in the realm of modern physics.
Electromagnetism
Electromagnetism is the scientific study of charge and the forces and fields that are connected to charge. Electricity and magnetism are two components of the phenomenon known as electromagnetic.
Electric and magnetic forces may be observed in areas known as electric and magnetic fields. These fields possess inherent characteristics and can occupy space at a considerable distance from the charge or current that produced them. Interestingly, electric fields can generate magnetic fields and vice versa, regardless of the presence of any external charge.
Michael Faraday, an English scientist, discovered that a magnetic field that is changing generates an electric field.
Michael Faraday's law of electromagnetic induction states that a change in magnetic field through a circuit induces an electromotive force (EMF) and therefore an electric current. This principle is the basis of many applications, including electric generators and transformers.
emf = −dΦdt
This discovery served as the foundation for the creation of electric power. On the other hand, the Scottish scientist James Clerk Maxwell inferred that a magnetic field is generated when there is a variation in an electric field. Maxwell's mathematical equations integrated light and wave phenomena into the field of electromagnetic. He demonstrated the coexistence of electric and magnetic fields as waves of electromagnetic radiation, where the dynamic fields support each other. Electromagnetic waves that propagate across space without relying on any material medium include radio and television waves, microwaves, infrared rays, visible light, ultraviolet light, X-rays, and gamma rays. All of these waves propagate at an identical pace, which is the speed of light, around 300,000 kilometers or 186,000 miles per second. The only distinction between them is in the varying frequency of their electric and magnetic fields' oscillations.
Electromagnetism encompasses the study of electricity, which focuses on the behavior of collections of electric charge, including the arrangement of charge inside substances and the movement of charge between locations. Materials are categorized as conductors or insulators based on their ability to allow charges to travel freely through their component matter. Electric current is the quantification of the movement of electric charges. The principles that regulate currents in materials are significant in technology, especially in the generation, transmission, and regulation of energy.
Find a professional private tutor and take a physics class on Superprof!
Thermodynamics
Thermodynamics is the scientific study of the interplay between heat, work, temperature, and energy. Thermodynamics is the study of how energy is transferred between different locations and transformed between different forms. The fundamental idea is that heat is a type of energy that corresponds to a specific quantity of mechanical labor. The fundamental principles of thermodynamics are:
- The zeroth law of thermodynamics. If two systems are both in thermal equilibrium with a third system, then they are also in thermal equilibrium with each other. This characteristic renders thermometers suitable for use as the "third system" and for the establishment of a temperature scale.
- The first principle of thermodynamics is often known as the principle of energy conservation. The change in a system's internal energy is determined by the net heat given to the system from its surroundings and the net work done by the system on its surroundings. Put simply, energy cannot be generated or annihilated, but rather transformed from one state to another.
- The second law of thermodynamics states that heat does not naturally go from a colder area to a hotter area. As a result, the entropy of a closed system, which is the amount of heat energy per unit temperature, gradually grows over time until it reaches its maximum value. Hence, in closed systems, there is a natural tendency towards reaching a state of equilibrium when entropy is maximized and no energy remains for performing meaningful tasks.
- The third law of thermodynamics. As the temperature approaches absolute zero, the entropy of a perfect crystal of an element in its most stable state decreases and trends toward zero. An absolute scale for entropy may be developed, which statistically quantifies the level of randomness or disorder in a system.
Relativity
Relativity refers to a set of comprehensive physical theories developed by the physicist Albert Einstein, who was originally from Germany. Einstein revolutionized the field of physics by introducing his theories of special relativity in 1905 and general relativity in 1915.
Through this, he challenged and reshaped the fundamental conceptions of space, time, matter, energy, and gravity, overturning previous beliefs. Relativity, in addition to quantum mechanics, is fundamental to contemporary physics. Relativity is particularly valuable for comprehending cosmic phenomena and the spatial structure of the cosmos.
Special relativity applies only to things that are in motion relative to inertial frames of reference. In other words, these objects are traveling uniformly about one other, and an observer cannot differentiate between them by purely mechanical investigations. The theory of special relativity, starting from the behavior of light and other forms of electromagnetic radiation, deduces implications that contradict our everyday experiences yet have been extensively validated via tests. Special relativity has demonstrated that the speed of light is an upper limit that may be approached but not surpassed by any physical entity.
This discovery gave rise to the renowned equation in physics, E = mc2, and has also resulted in intriguing phenomena like the "twin paradox."
The Twin Paradox is a thought experiment in special relativity where one twin embarks on a high-speed journey into space while the other twin stays on Earth. When the traveling twin returns, they will be younger than the twin who remained on Earth, demonstrating the concept of time dilation.
🕰️ Time Dilation in Special Relativity is a phenomenon predicted by Einstein's theory of special relativity, where time passes differently for objects in motion relative to each other. This effect becomes significant as speeds approach the speed of light
"General relativity" is a branch of physics that focuses on the phenomenon of gravity, which is one of the fundamental forces governing the behavior of the universe. (The remaining forces are electromagnetism, the strong force, and the weak force.) Gravity governs the overall behavior of objects on a big scale. Therefore, general relativity explains the physical processes that occur on a grand scale, such as the movement of planets, the life and death of stars, the existence of black holes, and the development of the universe.
Searching for IIT JAM coaching in Delhi for physics? Look no further! Find your tutor on Superprof today!
Quantum Physics Theory
Quantum physics is the discipline that investigates the properties of energy and matter at their most fundamental level. This field of study examines the characteristics and actions of the fundamental components that make up the Universe. Quantum physics focuses on the study of subatomic particles, including electrons, photons, neutrinos, and others. However, quantum processes have a pervasive influence on all scales of existence.
Quantum mechanics, a branch of physics, is the study of how very small particles exhibit both particle-like and wave-like properties. This phenomenon is known as "wave-particle duality."
By definition it is the study of matter and energy at the most fundamental level, aiming to uncover the properties and behaviors of the very building blocks of the universe.
Currently, the ideas of quantum theory are being utilized in several scientific disciplines as well as our daily lives. Quantum mechanics is employed to elucidate the many characteristics of the cosmos and unveil the specific behaviors of subatomic particles, including protons, electrons, neutrons, photons, and others.
In addition to its usage in Physics, quantum mechanics is also employed in the field of chemistry, where it is referred to as quantum chemistry. Quantum mechanics provides a precise understanding of chemical bonding processes, and the majority of computations conducted in contemporary computational chemistry rely on quantum mechanics.
Most of the present technology is primarily founded on the principles of quantum theory, in which quantum effects play a vital role. Additional uses of quantum theory may be found in:
- Quantum optics
- Quantum computing
- Light-emitting diodes
- Superconducting magnets
- Optical amplifiers and lasers
- Transistors
- Semiconductors
- Magnetic resonance imaging
- Electron microscopy
Recent Developments in Physics [2000-2024]
Physics has not seen significant revolutions in recent years, such as those that occurred in the early 1900s. However, the ideas and advancements from that period are still producing results and contributing to ongoing progress in the field. The following are the most groundbreaking developments in Physics in the past 25 years:
- 2000 – Quark-gluon plasma found
- 2000 – Tau neutrino found
- 2001 – Solar neutrino oscillation observed, resolving the solar neutrino problem
- 2003 – WMAP observations of the cosmic microwave background
- 2004 – Exceptional properties of graphene discovered
- 2007 – Giant magnetoresistance recognized (Nobel prize, Albert Fert and Peter Grünberg)
- 2008 – a 16-year study of stellar orbits around Sagittarius A* provides strong evidence for a supermassive black hole at the center of the Milky Way galaxy
- 2009 – Planck begins observations of the cosmic microwave background
- 2012 – Higgs boson found by the Compact Muon Solenoid and ATLAS experiments at the Large Hadron Collider
- 2015 – Gravitational waves are observed
- 2016 – Topological order – topological phase transitions and order – recognized (Nobel prize, David J. Thouless, F. Duncan M. Haldane and J. Michael Kosterlitz)
- 2019 – First image of a black hole
- 2023 – Experimental evidence of stochastic gravitational wave background[14]
- 2023 – First "image" of the Milky Way in neutrinos instead of light
Discover your perfect online physics tutor when you search on Superprof today!
Enjoyed this article? Leave a rating!
Loading...
