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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Glossary of physics | 5/13 | https://en.wikipedia.org/wiki/Glossary_of_physics | reference | science, encyclopedia | 2026-05-05T07:51:11.278375+00:00 | kb-cron |
Brownian motion Also pedesis. The apparently random movement of particles suspended in a fluid (liquid or gas) resulting from their continuous bombardment by fast-moving atoms or molecules in the gas or liquid.
bubble A globule of a gaseous substance immersed or suspended in a liquid; e.g. a pocket of air completely enclosed by water, usually but not necessarily assuming a spherical shape.
Bulk modulus A measure of a substance's resistance to uniform compression defined as the ratio of the infinitesimal pressure increase to the resulting relative decrease of the volume. Its base unit is the pascal.
buoyancy An upward force exerted by a fluid that opposes the weight of an immersed object.
== C ==
calculus A branch of mathematics that studies change and has two major sub-fields: differential calculus (concerning rates of change and slopes of curves), and integral calculus (concerning accumulation of quantities and the areas under and between curves). These two branches are related to each other by the fundamental theorem of calculus.
capacitance The ratio of the change in the electric charge of a system to the corresponding change in its electric potential. There are two closely related notions of capacitance: self capacitance and mutual capacitance. Any object that can be electrically charged exhibits self capacitance. A material with a large self capacitance holds more electric charge at a given voltage than one with low capacitance. The notion of mutual capacitance is particularly important for understanding the operations of the capacitor, one of the three elementary linear electronic components (along with resistors and inductors).
capacitive reactance An opposition to the change of voltage across an electrical circuit element. Capacitive reactance
X
C
{\displaystyle \scriptstyle {X_{C}}}
is inversely proportional to the signal frequency
f
{\displaystyle \scriptstyle {f}}
(or angular frequency, ω) and the capacitance
C
{\displaystyle \scriptstyle {C}}
.
capacitor An electrical circuit element consisting of two conductors separated by an insulator (also known as a dielectric).
Carnot cycle A theoretical ideal thermodynamic cycle proposed by French physicist Nicolas Léonard Sadi Carnot in 1824 and expanded upon by others in the 1830s and 1840s. It provides an upper limit on the efficiency that any classical thermodynamic engine can achieve during the conversion of heat into work, or conversely, the efficiency of a refrigeration system in creating a temperature difference by the application of work to the system. It is not an actual thermodynamic cycle but is a theoretical construct.
Cartesian coordinate system A coordinate system that specifies each point uniquely in a plane by a set of numerical coordinates, which are the signed distances to the point from two fixed perpendicular oriented lines, measured in the same unit of length. Each reference line is called a coordinate axis or just axis (plural axes) of the system, and the point where they meet is called the origin, at ordered pair (0, 0). The coordinates can also be defined as the positions of the perpendicular projections of the point onto the two axes, expressed as signed distances from the origin.
cathode The electrode through which a conventional electric current flows out of a polarized electrical device; the direction of current flow is, by convention, opposite to the direction of electron flow, and so electrons flow into the cathode. In a galvanic cell, the cathode is the positive terminal or pole which accepts electrons flowing from the external part of an electrical circuit. However, in an electrolytic cell, the cathode is the wire or plate having excess negative charge, so named because positively charged cations tend to move towards it. Contrast anode.
cathode ray
cation A positively charged ion. Contrast anion.
celestial mechanics
Celsius scale Also centigrade scale. A scale and unit of measurement of temperature.
center of curvature
center of gravity The point in a body around which the resultant torque due to gravity forces vanish. Near the surface of the earth, where gravity acts downward as a parallel force field, the center of gravity and the center of mass are the same.
center of mass Within a given distribution of mass, the unique point in space at which the weighted relative position of the distributed mass sums to zero.
center of pressure
centigrade See Celsius scale.
central-force problem A classic problem in potential theory involving the determination of the motion of a particle in a single central potential field. The solutions to such problems are important in classical mechanics, since many naturally occurring forces, such as gravity and electromagnetism, are central forces.
centrifugal force The apparent outward force that draws a rotating body away from the centre of rotation. It is caused by the inertia of the body as the body's path is continually redirected.
centripetal force A force which keeps a body moving with a uniform speed along a circular path and is directed along the radius towards the centre.
cGh physics Any attempt in mainstream physics to unify existing theories of relativity, gravitation, and quantum mechanics, particularly by envisioning the three universal constants fundamental to each field – the speed of light (
c
{\displaystyle c}
), the gravitational constant (
G
{\displaystyle G}
), and the Planck constant (
h
{\displaystyle h}
) – as the edges of a three-dimensional cube, at each corner of which is positioned a major sub-field within theoretical physics according to which of the three constants are accounted for by that sub-field and which are ignored. One corner of this so-called "cube of theoretical physics", where all three constants are accounted for simultaneously, has not yet been satisfactorily described: quantum gravity.
chain reaction A sequence of reactions in which a reactive product or byproduct causes additional similar reactions to take place.
change of base rule
charge carrier
chemical physics A branch of chemistry and physics that studies chemical processes from the point of view of physics by investigating physicochemical phenomena using techniques from atomic and molecular physics and condensed matter physics.
chromatic aberration
circular motion