Physics terms starting with M

Malleability Condensed Matter & Materials Physics Qualitative / Quantitative Plastic Strain A material's physical ability to deform plastically under compressive stress without cracking, typically tested by hammering or rolling into thin sheets. Compressive strain tolerance without cracking

Malus's Law Optics W/m² The law stating that intensity of linearly polarized light transmitted through an analyzer is proportional to the squared cosine of the angle between polarizer and analyzer transmission axes. I = I0 cos² θ

Mantle Convection Geophysics & Environmental Physics cm/year (Convection Motion Speed) The slow, highly viscous thermal convection currents within Earth's solid silicate mantle transporting internal core heat toward the surface. Ra = (ρ g α ΔT d³) / (κ η) (Rayleigh Number > Ra_critical)

Martensitic Transformation Condensed Matter & Materials Physics Transformation Temperature M_s A rapid, diffusionless solid-state phase transformation driven by collective lattice shear displacement of atoms. Diffusionless shear transformation: Austenite (FCC) → Martensite (BCT)

Mass Foundations of Physics kg A fundamental intrinsic property of matter that quantifies both the amount of substance in an object and its inertia (resistance to acceleration). m = F / a

Mass Defect Nuclear & Particle Physics u (Atomic Mass Units) or MeV/c² The difference between the total mass of an atom's individual free nucleons and the actual smaller mass of the bound atomic nucleus. Δm = Z m_p + (A - Z) m_n - M_nucleus

Mass-Energy Equivalence Astrophysics, Cosmology & Relativity Joules or MeV / GeV The fundamental relativistic principle stating that mass and energy are directly proportional and interchangeable physical quantities. E = m c² = γ m₀ c²

Matrix Mechanics Mathematical & Computational Physics Matrix Operator Algebra An algebraic formulation of quantum mechanics created by Werner Heisenberg in 1925 expressing physical observables as infinite-dimensional matrices. p̂ q̂ - q̂ p̂ = -i ℏ I, Ĥ = H(q̂, p̂)

Matter Foundations of Physics kg, m³ Anything that possesses mass, occupies volume, and is composed of fundamental particles such as quarks and leptons. E = mc²

Maximum Height Classical Mechanics m The maximum vertical elevation reached by a projectile above its launch level, where vertical velocity momentarily becomes zero. H = (v0² sin² θ) / (2 g)

Maxwell Relations Thermodynamics & Statistical Physics Various A set of thermodynamic equations derived from equality of second partial derivatives of thermodynamic potentials (U, H, F, G). (∂T/∂V)_S = -(∂P/∂S)_V, (∂T/∂P)_S = (∂V/∂S)_P, etc.

Maxwell's Equations Electromagnetism & Electronics Various SI Units The set of four fundamental partial differential equations that unify electricity, magnetism, and optics into classical electrodynamics. ∇·E = ρ/ε₀, ∇·B = 0, ∇×E = -∂B/∂t, ∇×B = μ₀J + μ₀ε₀∂E/∂t

Maxwell-Boltzmann Distribution Thermodynamics & Statistical Physics s/m The probability distribution describing particle speeds in an ideal gas in thermal equilibrium. f(v) = 4π (m / (2π kB T))^(3/2) v² exp(-m v² / (2 kB T))

Mean Free Path Thermodynamics & Statistical Physics m The average distance traveled by a moving gas particle between successive collisions with other particles. λ = 1 / (√2 π d² n_V)

Mean Life Nuclear & Particle Physics Seconds or Years The average expected lifetime of a radioactive nucleus before undergoing radioactive decay. τ = 1 / λ = t_½ / ln(2) ≈ 1.443 t_½

Mechanical Advantage Classical Mechanics Dimensionless The factor by which a simple machine multiplies input effort force to overcome load resistance. MA = F_output / F_input

Mechanical Energy Classical Mechanics J The sum of kinetic energy and potential energy in a physical system. E_mech = KE + PE

Medical Lasers Biophysics & Medical Physics W or J/cm² (Fluence) Laser devices engineered for surgical cutting, tissue coagulation, and photomedical treatments exploiting specific light-tissue absorption interactions. Selective Photothermolysis: Laser Pulse Duration ≤ Thermal Relaxation Time τ_r

Medical Linear Accelerator (LINAC) Biophysics & Medical Physics MV (Megavoltage Photon Beams 6–18 MV) A high-energy medical accelerator generating megavoltage X-ray photon or electron beams for external beam radiation cancer therapy. RF Cavity Electron Acceleration to 6–18 MeV → Bremsstrahlung X-Rays

Medical Ultrasound Biophysics & Medical Physics MHz (Frequency 2–15 MHz) & MRayl (Acoustic Impedance) A non-invasive diagnostic imaging modality using high-frequency acoustic waves (2–15 MHz) to image soft tissue reflection interfaces. R = ((Z₂ - Z₁) / (Z₂ + Z₁))², Z = ρ c (Acoustic Impedance)

Meissner Effect Condensed Matter & Materials Physics T (Magnetic Flux Density B) The active expulsion of magnetic flux from the interior of a superconductor as it cools below its critical temperature T_c. B_internal = 0, M = -H (Perfect Diamagnetism)

Membrane Potential Biophysics & Medical Physics mV (Millivolts) The electrical potential difference across a biological cell membrane produced by asymmetric ion concentration gradients. V_m = V_in - V_out (Resting Potential ≈ -70 mV)

Mesons Nuclear & Particle Physics Composite Boson Class Hadronic subatomic particles composed of one valence quark and one valence antiquark bound by gluons. Quark Content: q q̄, Spin = 0, 1, Baryon Number = 0

Metamaterials Condensed Matter & Materials Physics Dimensionless Index n < 0 Artificially engineered composite structures designed with subwavelength resonant features that display electromagnetic properties not found in natural materials. n_refractive = - √(ε_r μ_r) (Negative Refractive Index)

Terms starting with M