Terms starting with O
15 terms
Ocean Acidification
The ongoing long-term reduction in the pH of Earth's oceans caused by the absorption of anthropogenic carbon dioxide from the atmosphere.
Geophysics & Environmental PhysicsOcean Currents
Continuous, directed large-scale movements of seawater generated by wind stress, Coriolis force, temperature, salinity differences, and…
Electromagnetism & ElectronicsOhm's Law
An empirical relation stating that the electric current flowing through an ohmic conductor is directly proportional to the applied voltage…
Astrophysics, Cosmology & RelativityOlbers' Paradox
The apparent paradox that if the universe were static, infinite, and uniformly populated with stars, the night sky should be uniformly…
Waves, Oscillations & AcousticsOpen Organ Pipes
A cylindrical acoustic pipe open at both ends, containing displacement antinodes at both openings.
Electromagnetism & ElectronicsOperational Amplifier (Op-Amp)
A high-gain DC-coupled electronic voltage amplifier with differential inputs and single-ended output.
OpticsOptical Axis
The imaginary central straight line passing through the centers of curvature of all optical elements in a rotationally symmetric system.
OpticsOptical Fiber
A flexible, transparent glass or plastic fiber that transmits light signals across long distances via total internal reflection.
OpticsOptical Power
A measure of a lens or curved mirror's degree of light convergence or divergence, equal to the reciprocal of its focal length.
Biophysics & Medical PhysicsOptical Tweezers
A biophysical instrument using a strongly focused laser beam to trap, manipulate, and exert piconewton forces on microscopic dielectric…
Quantum & Atomic PhysicsOrbital Angular Momentum
The quantized angular momentum of a quantum particle associated with its orbital spatial motion around a central force field.
Classical MechanicsOrbital Velocity
The speed required for a body to maintain a stable circular orbit around a primary gravitational mass at a given radius.
Foundations of PhysicsOrder of Magnitude
An exponential estimate of the size of a quantity, expressed as the power of ten closest to the numerical value.
Biophysics & Medical PhysicsOsmosis
The net passive diffusion of solvent molecules (water) across a selectively permeable membrane from lower solute concentration toward…
Waves, Oscillations & AcousticsOvertones
Any resonant frequency higher than the fundamental frequency in a musical sound.