Biophysics Exam Review Flashcards

Comprehensive set of vocabulary flashcards created from the Biophysics exam review notes covering mechanics, fluids, electricity, optics, radiation, and medical physics.

Biomechanics

The branch of physics that studies internal and external forces acting on the human body and the physical effects produced by these forces.

Unit of Constant $E$ in Sound Velocity Equation

Derived from the velocity equation $v = \frac{E}{\rho}$, the unit of constant $E$ is $\frac{\text{kg}}{\text{m} \times \text{s}^2}$ (or $\text{kg} \times \text{m}^{-1} \times \text{s}^{-2}$).

Force

Any interaction that is capable of deforming a body or changing its state of motion; to fully define a force, its point of application, line of action (support), direction, and magnitude must be known.

Law of Conservation of Momentum

States that the total momentum of an isolated system remains constant regardless of any internal interactions or changes occurring within it.

Hydrostatic Pressure (in Arterial Tension)

The pressure component that varies with fluid depth/height and directly influences arterial blood pressure levels at different locations throughout the human body.

Poiseuille's Law

A fluid dynamics law stating that the volumetric flow rate $Q$ of a fluid through a cylindrical tube of radius $R$ is directly proportional to the pressure difference $(P_1 - P_2)$ across the tube: $Q = \frac{\frac{\text{d}V}{\text{d}t} \times \text{d}P}{\text{resistance}}$.

Surface Energy

The difference in energy per unit area that exists between molecules located at the surface layer of a liquid and those located inside the bulk volume.

Osmosis

The physical process of solvent transport across a semi-permeable membrane from a solution with lower solute concentration to one with higher solute concentration.

Specific Heat Capacity Formula

Expressed by the equation $c = \frac{\text{d}Q}{m \times \text{d}T}$, representing the thermal energy required to change the temperature of a unit mass $m$ by $\text{d}T$.

Short Circuit

A condition in an electrical circuit created when two opposing charge carriers connect directly with negligible resistance, producing high current intensity given by $I = \frac{E}{r}$.

Joule's Law

Defines the thermal energy generated by an electric current passing through a conductor, expressed as $W = U \times I \times t$, where $U$ is voltage, $I$ is current intensity, and $t$ is time.

Physiological Effects of Electric Current

Currents up to $10 \times 10^{-3} \text{ A}$ produce mild sensations; $10 \times 10^{-3} \text{ A}$ to $20 \times 10^{-3} \text{ A}$ cause pain and muscle cramps; $70 \times 10^{-3} \text{ A}$ to $100 \times 10^{-3} \text{ A}$ cause respiratory distress and circulatory disruption; $100 \times 10^{-3} \text{ A}$ to $200 \times 10^{-3} \text{ A}$ cause ventricular fibrillation and cardiac arrest.

Mass Spectrograph

An instrument operating on the principle of separating charged particles by causing them to travel along specific circular trajectories in a magnetic field based on their mass-to-charge ratio.

Faraday's First Law of Electrolysis

States that the mass $m$ of a substance deposited on an electrode during electrolysis is directly proportional to the total electric charge passing through the solution: $m = k \times I \times t$.

Optical Lens

A transparent medium bounded by two curved surfaces (or one plane and one curved surface) that refracts light rays to form images.

Optically Active Substances

Substances that possess the ability to rotate the plane of polarization of linearly polarized light, such as sucrose, lactic acid, and tartaric acid.

Hyperopia

A visual defect (farsightedness) where light rays focus behind the retina; corrected using converging (convex) optical lenses.

Malus's Law

A quantitative law describing light polarization intensity, expressed as $I = I_0 \times \text{cos}^2(\theta)$, where $I_0$ is the initial intensity and $\theta$ is the angle between polarizer axes.

Polarimeter

A scientific instrument whose working principle is based on measuring the degree and direction of optical rotation produced by optically active solutions.

X-Rays

Electromagnetic waves with wavelengths between $10 \times 10^{-9} \text{ m}$ and $0.001 \times 10^{-9} \text{ m}$, produced when high-velocity electrons from a cathode bombard an anode target inside a vacuum tube.

Absorbed Radiation Dose

The amount of radiation energy absorbed per unit mass of matter, measured in the SI unit Gray ($\text{Gy}$).

Exposure Radiation Dose

A measure of the total electric charge of ions produced in a unit mass of dry air by X-rays or gamma rays, measured in Coulombs per kilogram ($\text{C} \times \text{kg}^{-1}$) or Roentgens ($\text{R}$).

Doppler Effect

The shift in observed wave frequency caused by relative motion between the wave source and the observer; used in medical diagnostics for monitoring blood flow.

Fick's Law of Diffusion

Describes mass transport during diffusion, stating that the mass rate of diffusion across a concentration gradient is given by $m = -D \times \frac{\text{d}c}{\text{d}x} \times A \times t$.

Positively Charged Body

A body possessing a deficit of electrons relative to protons; can be electrified via friction, contact, induction, the photoelectric effect, or thermionic emission.

Equipotential Surfaces

Surfaces where every point shares the exact same electric potential, standing perpendicular to electric field lines at all intersections.

Ohm's Law for a Circuit Segment

States that current intensity $I$ through a circuit segment is directly proportional to potential difference $U$ across it and inversely proportional to resistance $R$: $I = \frac{U}{R}$.

Lorentz Force

The magnetic force experienced by a charged particle moving through a magnetic field, calculated as $F = q \times v \times B \times \text{sin}(\theta)$.

Ampere's Force

The mechanical force exerted by a magnetic field on a current-carrying conductor, expressed as $F = I \times L \times B \times \text{sin}(\theta)$.

Nuclear Magnetic Resonance (NMR)

A medical imaging and physical phenomenon where atomic nuclei absorb and re-emit electromagnetic energy when subjected to a strong static magnetic field.

Mammography

A diagnostic medical imaging technique that utilizes low-energy X-rays to inspect the human breast for screening and detection of lesions.