physics definitions nov 2026

expansion

an increase in volume of a substance while its mass remains the same

temperature

the measure of the average kinetic energy of all the particles of a substance

diffusion

the process whereby particles of a substance move form an area of high concentration to one of low concentration

density

the mass per unit volume of a substance,

mass

a measure of the amount of matter in an object

element

an element is a pure substance which consists of only one kind of atom that cannot be broken down into anything simpler by either physical or chemical means

molecule

a group of atoms held together by strong forces called chemical bonds

electrical conductor

a substance through which electrical charge carriers move easily when connected to an electrical potential difference

short circuit

an unintended ,no -resistance connection between two points in an electrical circuit

potential difference

the work done per unit positive charge

current

the rate of flow of charge