Physics

Items

• ionosphere

  A region of Earth’s upper atmosphere ionized by solar radiation, important for radio wave transmission.
• isentropic

  A process with constant entropy, usually ideal and reversible with no heat transfer.
• isobaric

  A process that occurs at constant pressure.
• isochoric

  A process that occurs at constant volume.
• isothermal

  A process that occurs at constant temperature.
• isotherm

  A line on a graph or map connecting points of equal temperature.
• isotope

  Atoms of the same element with different numbers of neutrons, hence different mass numbers.
• isotropic

  Having identical properties in all directions; often used in materials science and cosmology.
• kinematics

  The branch of physics that describes the motion of objects (position, velocity, acceleration) without considering the forces that cause the motion.
• kinetic

  Relating to motion. In physics, it often refers to kinetic properties like energy or velocity.
• kinetic energy

  The energy possessed by a body due to its motion, calculated as 𝐾𝐸 = 1 𝑚𝑣2, 2 where m is mass and v is velocity.
• label

  A descriptive tag or identifier used in diagrams, graphs, and scientific equipment to denote quantities, units, or variables.
• laminar

  Describes smooth, orderly fluid flow in parallel layers with minimal mixing, typical at low flow velocities and low Reynolds numbers.
• laser

  A device that emits a highly focused, coherent beam of light at a single wavelength or frequency.
• lateral

  Pertaining to the side. In scientific contexts, often describes sideways direction or movement (e.g., lateral force, lateral displacement).
• lattice

  A regular, repeating arrangement of atoms, ions, or molecules in a crystal or other structured material.
• layer

  A thin sheet or level of material or substance, often used in contexts such as geological strata, atmosphere, or nanomaterials.
• lemma

  In mathematics and logic, a proven statement used as a stepping-stone to prove a larger theorem or result.
• length

  A measure of distance between two points. It is a fundamental physical quantity in the SI system, measured in meters (m).
• lens

  A transparent optical component with one or more curved surfaces that refracts light to converge or diverge rays, forming images.
• lepton

  A fundamental particle that does not undergo strong interactions; includes electrons, muons, tau particles, and neutrinos.
• level

  A specific value or state in a system, such as energy level in atoms or sea level in geography.
• light

  Electromagnetic radiation visible to the human eye (roughly 400–700 nm wavelength), and more broadly, includes ultraviolet and infrared.
• line

  An idealized one-dimensional figure having no thickness and extending infinitely in both directions; used in geometry and graphs.
• liquid

  A state of matter with a fixed volume but no fixed shape, flowing to conform to its container.