Vijay Shankar Sharma
Textbook physics terms. Not a BFUT reinterpretation. 371 terms. Textbook meanings only.
371 terms. Page 8 of 8.
math-methods · intro
A physical quantity that has both a magnitude and a specific direction, requiring more than a single number to fully describe it, in contrast to a scalar, which has magnitude alone. Force, velocity, and acceleration are all vector quantities, typically represented graphically as arrows, with the arrow's length indicating magnitude and its orientation indicating direction. Vectors are combined using specific rules of vector addition rather than simple arithmetic.
mechanics · intro
A vector quantity describing both the speed of an object and the direction in which it is moving, calculated as the rate of change of an object's position over time. Unlike speed, which is a scalar, velocity fully specifies motion, so two objects moving at the same speed but in different directions have different velocities. Acceleration is defined as the rate of change of velocity over time.
quantum · intermediate
A theoretical concept in quantum field theory representing a temporary, fleeting disturbance in a quantum field that mediates interactions between real particles but does not itself satisfy the usual energy-momentum relationship required for an observable particle, existing only for an extremely brief time allowed by the uncertainty principle. Virtual particles are a useful calculational tool in Feynman diagrams, representing the exchange processes, such as photon exchange, that produce forces between particles.
mechanics · intro
A measure of a fluid's internal resistance to flow, or its thickness, arising from friction between adjacent layers of the fluid as they move at different speeds relative to each other. Honey has a much higher viscosity than water, meaning it flows far more sluggishly. Viscosity generally decreases with increasing temperature in liquids, which is why oil flows more easily when warm, and it plays a central role in fluid dynamics and engineering applications like lubrication.
optics · intro
The narrow portion of the electromagnetic spectrum that the human eye can detect, spanning wavelengths from roughly 380 nanometers, perceived as violet, to about 700 nanometers, perceived as red. Visible light represents only a tiny fraction of the full electromagnetic spectrum, yet it is the primary way humans and many other organisms gather information about their surroundings, since it is the range most strongly emitted by the Sun and least absorbed by Earth's atmosphere.
em · intro
The SI unit of electric potential difference, or voltage, defined as the potential difference that would impart one joule of energy to a charge of one coulomb passing between two points. Named after Italian physicist Alessandro Volta, inventor of the first chemical battery, the volt is a standard measurement used throughout electrical engineering and everyday electronics, from small batteries rated at a few volts to power lines carrying hundreds of thousands of volts.
particle · intermediate
The elementary particles that mediate the weak nuclear force, one of the four fundamental forces of nature, responsible for processes such as radioactive beta decay. The W boson, which comes in positively and negatively charged versions, and the electrically neutral Z boson are unusually massive compared to other force-carrying particles, a property that makes the weak force extremely short-ranged, and both were directly detected experimentally in 1983.
mechanics · intro
The SI unit of power, defined as one joule of energy transferred or converted per second. Named after Scottish engineer James Watt, whose improvements to the steam engine were pivotal to the Industrial Revolution, the watt is used to rate the power output or consumption of devices ranging from light bulbs and household appliances to car engines and power plants, often expressed in larger units like kilowatts or megawatts.
waves · intro
A disturbance that travels through space and time, transferring energy from one location to another without necessarily transporting matter along with it. Waves can be mechanical, requiring a physical medium such as air or water to propagate, like sound waves, or electromagnetic, capable of traveling through the vacuum of space, like light. Waves are broadly classified as transverse or longitudinal based on the relationship between the direction of oscillation and the direction of travel.
quantum · intro
A fundamental concept in quantum mechanics describing how entities such as light and matter exhibit both wave-like and particle-like properties, depending on the type of experiment used to observe them. Light can behave as a continuous wave, producing interference patterns, or as discrete particles called photons, depending on the situation, and matter particles like electrons similarly display wave properties, such as diffraction, alongside their particle-like behavior. This duality challenged classical intuitions and led directly to the development of quantum theory.
quantum · intermediate
A mathematical function used in quantum mechanics to fully describe the quantum state of a system, encoding the probabilities of finding a particle in different positions, momenta, or other measurable states. According to the Born rule, the probability of finding a particle at a given location is proportional to the square of the magnitude of the wavefunction at that point. The wavefunction evolves predictably over time according to the Schrodinger equation until a measurement is made.
quantum · intermediate
A concept in quantum mechanics describing the apparent, abrupt change of a system's wavefunction from a superposition of multiple possible states into a single definite state upon measurement. Before measurement, a quantum system can exist in a combination of several possible outcomes simultaneously, but the act of measuring forces the system to settle into just one of them. The precise physical interpretation of this collapse remains a subject of ongoing debate among physicists and philosophers of science.
waves · intro
The distance between two successive corresponding points on a wave, such as from one crest to the next, or from one trough to the next, typically measured in meters or, for light, often in nanometers. Wavelength is inversely related to frequency for a wave traveling at a fixed speed; shorter wavelengths correspond to higher frequencies. For visible light, wavelength determines the perceived color.
particle · intro
One of the four fundamental forces of nature, responsible for processes such as beta decay, in which a neutron transforms into a proton or vice versa, and playing an essential role in the nuclear fusion reactions that power the Sun. The weak force is mediated by the W and Z bosons, which are unusually massive compared to other force carriers, making the weak force extremely short-ranged and, despite its name, actually stronger than gravity at subatomic distances.
cosmology · intermediate
The subtle, statistical distortion of the observed shapes of distant background galaxies caused by the gravitational influence of intervening mass, including dark matter, along the line of sight, distinct from the more dramatic distortions seen in strong gravitational lensing. Because the effect on any single galaxy is too small to detect individually, astronomers statistically analyze the coherent alignment of many galaxy shapes across a region of sky to map the underlying distribution of both visible and dark matter.
mechanics · intro
The gravitational force exerted on an object by a nearby massive body, such as Earth, calculated as the object's mass multiplied by the local gravitational acceleration. Unlike mass, which remains constant regardless of location, weight varies depending on the strength of the local gravitational field; an object weighs less on the Moon than on Earth, even though its mass is unchanged. Weight is measured in newtons, the same unit used for force generally.
astro · intro
The dense, compact remnant left behind after a low- to medium-mass star, similar to the Sun, exhausts its nuclear fuel and sheds its outer layers, leaving behind a hot, slowly cooling core roughly the size of Earth but containing a mass comparable to the Sun. White dwarfs no longer generate energy through fusion and are supported against further gravitational collapse by electron degeneracy pressure, gradually cooling and dimming over billions of years.
mechanics · intro
The transfer of energy that occurs when a force acts on an object and causes it to move some distance in the direction of that force, calculated as the force multiplied by the displacement, or more precisely by the component of force parallel to the displacement. If a force is applied but no displacement occurs, such as pushing against an immovable wall, no work is done in the physics sense, even though effort is expended. Work is measured in joules, the same unit used for energy.
em · intro
A form of electromagnetic radiation with wavelengths shorter than ultraviolet light but longer than gamma rays, possessing enough energy to penetrate soft tissue while being absorbed more strongly by denser materials like bone, which makes X-rays valuable for medical and dental imaging. X-rays are produced when high-energy electrons are suddenly decelerated, often by striking a metal target, and they are also emitted naturally by extremely hot astrophysical sources such as the regions surrounding black holes and neutron stars.
quantum · intermediate
Also called: double-slit experiment
A landmark experiment performed by Thomas Young in 1801, in which light passing through two closely spaced narrow slits produced a pattern of alternating bright and dark bands, called an interference pattern, on a screen behind them. This result provided compelling evidence that light behaves as a wave, since only waves are known to interfere constructively and destructively in this characteristic way. A modern version of the experiment, performed with individual electrons or photons, also famously demonstrates wave-particle duality.
quantum · intermediate
The lowest possible energy that a quantum mechanical system can have, which remains nonzero even at absolute zero temperature, in contrast to classical physics, where a system at its lowest energy state would be expected to be completely motionless. Zero-point energy arises directly from the Heisenberg uncertainty principle, since a particle confined to a definite region cannot have exactly zero momentum, and it has measurable physical consequences, such as the Casimir effect between closely spaced conducting plates.