Acceleration: The rate of increase of speed or the rate of change of velocity.
Alternating Current: A continuous electric current that periodically reverses the direction, usually sinusoidally.
Ampere: The SI unit of electric current; the constant current that, when maintained in two parallel conductors of infinite length and negligible cross section placed 1 metre apart in free space, produces a force of 2 × 10–7 newton per metre between them. 1 ampere is equivalent to 1 coulomb per second.
Angstrom: A unit of length equal to 10–10 metre, used principally to express the wavelengths of electromagnetic radiations. It is equivalent to 0.1 nanometre.
Anion: A negatively charged ion; an ion that is attracted to the anode during electrolysis.
Antimatter: A form of matter composed of antiparticles, such as antihydrogen, consisting of antiprotons and positrons.
Atom: An atom is a particles of matter that uniquely defines a chemical elements.
Baryon: Any of a class of elementary particles that have a mass greater than or equal to that of the proton, participate in strong interactions, and have a spin of . Baryons are either nucleons or hyperons. The baryon number is the number of baryons in a system minus the number of antibaryons.
Becquerel: The derived SI unit of radioactivity equal to one disintegration per second.
Brownian Motion: The andom movement of microscopic particles suspended in a fluid, caused by bombardment of the particles by molecules of the fluid. First observed in 1827, it provided strong evidence in support of the kinetic theory of molecules.
Calorie: A unit of heat, equal to 4.1868 joules (International Table calorie). Or the quantity of heat required to raise the temperature of 1 gram of water by 1°C under standard conditions. It has now largely been replaced by the joule for scientific purposes.
Capacitance: The property of a system that enables it to store electric charge is known as capacitance.
Cathode Ray: A valve in which a beam of high-energy electrons is focused onto a fluorescent screen to give a visible spot of light. The device, with appropriate deflection equipment, is used in television receivers, visual display units, oscilloscopes, etc
Center of Gravity: The point through which the resultant of the gravitational forces on a body always acts.
Centrifugal Force: A fictitious force that can be thought of as acting outwards on any body that rotates or moves along a curved path.
Centripetal Force: A force that acts inwards on any body that rotates or moves along a curved path and is directed towards the centre of curvature of the path or the axis of rotation.
Charge: The attribute of matter by which it responds to electromagnetic forces responsible for all electrical phenomena is known as charge. It exist in two forms to which the signs negative and positive are arbitrarily assigned.
Charles' Law: The principle that all gases expand equally for the same rise of temperature if they are held at constant pressure: also that the pressures of all gases increase equally for the same rise of temperature if they are held at constant volume. The law is now known to be only true for ideal gases.
Conductor: The substance, body or system that allow current or heat to follow through them.
Convection: The process by which masses of relatively warm air are raised into the atmosphere, often cooling and forming clouds, with compensatory downward movements of cooler air.
Cosmic Ray: A radiation of high penetrating power that originates in outer space and consists partly of high-energy atomic nuclei.
Coulomb: The SI unit of electric charge; or waythe quantity of electricity transported in one second by a current of 1 ampere.
