Physics Flashcards
Law stating that the voltage drop across a resistor is proportional to the current flowing through it, given by the equation V = IR.
Ohm’s Law
A quantity that has magnitude but no direction.
Scalar
States that the sum of currents directed into a node or junction point in a current equals the sum of the currents directed away from that point.
Kirchhoff’s Junction Rule
Form of heat transfer where a heated fluid transfers energy by bulk flow and physical motion over another object, or a cooled fluid absorbs energy by the same means.
Convection
The impetus for current flow created by a voltage source, such as a battery or outlet.
Electromotive Force
States that if one object exerts a force on another, the other object exerts a force on the first that is equal in magnitude but opposite in direction; the law of “action and reaction.”
Newton’s Third Law
The rate at which the energy of flowing charges through a resistor or other device is dissipated, given by the equation P = IV.
Electric Power
A quantity that has both magnitude and direction.
Vector
Spherical mirrors have the appearance of a curved surface that is either concave or convex. A converging mirror is a concave mirror with a positive focal length, while a diverging mirror is a convex mirror with a negative focal length. Diverging mirrors always produce virtual images.
Spherical Mirror
A type of attractive force that molecules of a liquid feel toward molecules of another substance, such as in the adhesion of water droplets to a glass surface.
Adhesion
Form of heat transfer where the energy is carried by electromagnetic waves; the only form of heat transfer that can be carried out in a vacuum.
Radiation
State where the sum of the torques acting on a body is zero, giving it no net angular acceleration. An object may be in rotational equilibrium, translational equilibrium, or both simultaneously.
Rotational Equilibrium
A vector quantity describing the push or pull on an object. The SI unit for force is the newton (N).
Force
States that if no net force acts on an object, its velocity is constant.
Newton’s First Law
A force that does not cause dissipation of mechanical energy from a system. As such, the work performed is independent of the path taken. Examples include gravity and electrostatic forces. Elastic forces are nearly conservative.
Conservative Force
A scalar quantity describing the distance traveled divided by the time required to travel that distance.
Speed
State where the sum of the forces acting on an object is zero, giving it no net acceleration. An object may be in rotational equilibrium, translational equilibrium, or both simultaneously.
Translational Equilibrium
A scalar quantity used as a measure of an object’s inertia.
Mass
A conducting pathway that contains one or more voltage sources that drive an electric current along that pathway and through connected passive circuit elements (such as resistors).
Electric Circuit
A transparent device with a curvature that causes light to bend (refract) as it passes through. May be converging or diverging. A lens with a thick center that converges light rays at a point where the image is formed is called a converging lens. A lens with a thin center that diverges light after refraction and always forms a virtual image is called a diverging lens.
Lens
The natural tendency of a conductor to block current flow to a certain extent resulting in loss of energy or potential. Resistance is equal to the ratio of the voltage applied to the resulting current.
Resistance
Form of heat transfer where energy is transferred by molecular collisions or direct contact between two objects.
Conduction
Light that has been passed through a polarizing filter, allowing only the transmission of waves containing electric field vectors parallel to the lines of the filter.
Plane-Polarized Light
When superimposed waves are in phase, their amplitudes add (constructive interference). When superimposed light waves are out of phase, their amplitudes subtract (destructive interference).
Interference
A type of attractive force felt by liquid molecules toward each other. Cohesion is responsible for surface tension.
Cohesion
An insulating material placed between the two plates of a capacitor; used to increase capacitance. If the circuit is plugged into a current source, more charge will be stored. If the circuit is not plugged in, the voltage of the capacitor will decrease, indirectly increasing its capacitance. The strength of a dielectric is measured by the dielectric constant.
Dielectric
States that the sum of the voltage sources in a circuit loop is equal to the sum of voltage drops along that loop.
Kirchhoff’s Loop Rule
The distance between the focal point and the mirror or lens. For spherical mirrors, the focal length is equal to one-half the radius of curvature.
Focal Length
A mirror in which incident light rays remain parallel after reflection, always producing a virtual image that appears to be the same distance behind the mirror as the object is in front of the mirror.
Plane Mirror
A force that dissipates mechanical energy from a system. As such, the energy dissipated depends on the path taken from initial to final position. Examples include friction, air resistance, and viscous drag.
Nonconservative Force
States that when a pressure is applied to one point of an enclosed fluid, that pressure is transmitted in equal magnitude to all points within that fluid and to the walls of its container. This principle forms the basis of the hydraulic lift.
Pascal’s Principle
The spreading-out effect of light when it passes through a small slit opening.
Diffraction
Perpendicular component of the force caused when two forces push against each other, denoted by N.
Normal Force
The movement of thermal energy towards a state of thermodynamic equilibrium. Heat spontaneously transfers energy from the object with the higher temperature to the object with the lower temperature.
Heat Transfer
A relationship between variables such that an increase in one variable is associated with a decrease in the other: AB = constant.
Inverse Relationship
States that the net work performed on an object is related to its change in energy. In most applications, the work-energy theorem is used to relate work and kinetic energy.
Work-Energy Theorem
A material in which electrons cannot move freely.
Insulator
A material in which electrons can move with relative ease.
Conductor
The energy of an object due to its height above a given datum, calculated by the equation U = mgh and given in the SI unit of joules (J).
Gravitational Potential Energy
The point on some object or body where all of its mass is considered to be concentrated. In a uniform gravitational field, this is also the center of gravity.
Center of Mass
Concentric circles emanating from a source charge that cross its electric field lines perpendicularly. No work is required for a test charge to travel along the circumference of an equipotential line because the potential at every point along that line is the same.
Equipotential Lines
The apparent location of an object perceived through a lens or mirror. An image produced at a point where light does not actually pass through or converge is called a virtual image. An image produced at a point where the light rays actually converge or pass through is called a real image.
Image
Number of cycles per second measured in units of Hz, where 1 Hz = 1 cycle per second.
Frequency
The energy that holds the protons and neutrons together in the nucleus, defined by the equation E = mc², where m is the mass defect and c is the speed of light in a vacuum.
Binding Energy
A common method used to determine the direction of a vector created as the product of two vectors. The thumb points in the direction of the first vector, the fingers point in the direction of the second vector, and the palm points in the direction of the resultant.
Right-Hand Rule
An electric device used in circuits that is composed of two conducting plates separated by a short distance; these devices store electric charge.
Capacitor
The difference between an atom’s atomic mass and the sum of the masses of its protons and neutrons.
Mass Defect
States that for any process, the entropy of the universe either increases (for irreversible processes) or remains constant (for reversible processes).
Second Law of Thermodynamics
When an electric field is changing, it causes a change in the magnetic field and vice-versa, resulting in the propagation of the wave containing an electric and a magnetic field that are perpendicular to each other.
Electromagnetic Waves
A vector quantity describing the straight-line distance between an initial and the final position of some particle or object.
Displacement
States that two objects that are in thermal equilibrium with a third object are also in thermal equilibrium with each other. By extension, objects of the same temperature are in thermal equilibrium with no net transfer of heat.
Zeroth Law of Thermodynamics
The difference in electric potential between two points in an electric field, also called the voltage (ΔV).
Potential Difference
The acceleration of an object traveling in a circle that points toward the center of the circle. In uniform circular motion, it is equal in magnitude to the velocity squared divided by the radius of the circle transversed: a{c} = (v²)/r
Centripetal Acceleration
A quantity equal to the distance between any two equivalent consecutive points along a wave, such as two consecutive crests (peaks) or two consecutive troughs (valleys); expressed as λ.
Wavelength
States that went only conservative forces act on an object and work is done, energy is conserved and describe by the equation: ΔE = ΔU + ΔK = 0.
Conservation of Mechanical Energy
The speed of a wave, which is related to its frequency and wavelength by the equation v = fλ.
Wave Speed
A flow of charge per time. The flow of charge is motivated by a potential difference (voltage). Current is denoted I and can be calculated as Δq/Δt. Current is conventionally considered the theoretical movement of positive charge.
Current
A ubiquitous attractive force existing between any two objects, with magnitude directly proportional to the product of the two masses observed and inversely proportional to the square of their distance from each other: F{g} = (Gm{1}m{2})/r².
Gravity
The phenomenon observed when white light is incident on the face of a prism and emerges on the opposite side with all its wavelengths split apart, forming the visible spectrum. This occurs because λ is related to the index of refraction by the expression n = c/(fλ).
Dispersion
Equation describing the angle of refraction for a light ray passing from one medium to another, given by n{1}sinθ{1} = n{2}sinθ{2}, where n represents the index of refraction in each medium.
Snell’s Law
A mathematical function that is the inverse of the exponential function. Logarithms with base ten are called common logarithms (log); logarithms with Euler’s number (e ≈ 2.72) are called natural logarithms (ln).
Logarithm
The amount of work required to bring a test charge q{0} from infinity to a point within the electric field of some source charge Q, given by the equation U = q{0}V.
Electric Potential Energy
The law describing the electrostatic force that exists between two charges, q{1} and q{2}, given by the equation F = (kq{1}q{2})/r².
Coulomb’s Law
A relationship between variables such that an increase in one variable is associated with an increase in the other: A/B = constant.
Direct Relationship
The amount of heat required to change the phase of a substance, calculated by the equation q = mL, where q is heat, m is the mass of the substance, and L is the heat of transformation for that substance. The heat of transformation corresponding to the solid-liquid phase change is called the heat of fusion; that corresponding to liquid-gas is called the heat of vaporization.
Heat of Transformation
An antagonistic force that points parallel and opposite in direction to the direction of movement (or attempted movement) of an object. Related to a coefficient of friction and the normal force: Static friction: 0 ≤ f{s} ≤ μ{s}N. Kinetic friction: f{k} = μ{k}N
Frictional Force
The energy of an object in motion, calculated by the equation K = 1/2mv² and given in the SI unit of joules (J).
Kinetic Energy
The measure of internal friction in a fluid, often denoted by η. Viscosity is responsible for creating viscous drag, a nonconservative force analogous to air resistance.
Viscosity
A nuclear reaction in which a positron (β^+ or e^+) is emitted: ^A {Z} X ➝ ^A {Z - 1} Y + β^+.
Positron Decay
The pressure above and beyond atmospheric pressure. When the pressure at the surface is atmospheric pressure, the gauge pressure is given by ρgz, where ρ is the density of the fluid, g is acceleration due to gravity, and z is depth.
Gauge Pressure
The phenomenon observed when light of a certain frequency causes a metal to emit electrons. The minimum amount of energy required to emit an electron from a certain metal is called the work function. This quantity, denoted by W, is used to calculate the residual kinetic energy of an electron emitted by a metal, given by K = hf - W.
Photoelectric Effect
The rate at which work is done, given by the equation P = W/Δt, where W is work and t is time (in seconds). The SI unit for power is the watt (W).
Power
States that an object will accelerate in proportion to the net force acting on it: F{net} = ma.
Newton’s Second Law
The smoothest type of liquid flow through a tube wherein thin layers of liquid slide over one another. Occurs as long as the linear flow speed remains below a critical speed v{c}. Laminar flow can be represented by roughly parallel streamlines – lines that trace the path of water particles as they flow in a tube without ever crossing each other.
Laminar Flow
Equation describing the conservation of energy and liquid flow, given by P{1} + 1/2ρv²{1} + ρgh{1} = P{2} + 1/2ρv²{2} + ρgh{2}. According to the Venturi effect, for a given depth, linear flow speed and pressure are inversely related.
Bernoulli’s Equation
The electrostatic force that a source charge would exert on a positive test charge q{0} divided by the magnitude of that test charge: E = F/q{0}. Electric fields are represented by electric field lines – imaginary lines that show the direction in which a positive test charge is accelerated by the coulombic force due to the electric field of a source charge.
Electric Field
When a source emitting a sound and a detector receiving the sound move relative to each other, the perceived frequency f’ is less than or greater than the actual frequency emitted f, depending on whether the source and detector move toward or away from each other: f’ = f(v±v{D})/(v±v{s})
Doppler Effect
A measure of a capacitors ability to store charge at a given voltage; calculated by the ratio of the magnitude of charge on one plate to the voltage across the two plates: C = Q/V. The SI unit for capacitance is the farad (F).
Capacitance
A decrease in the amount of substance N at an exponential rate. Given by the equation: N = N{0} × e^(-λt).
Exponential Decay
A nuclear reaction in which a β-particle (e^-) is emitted: ^A {Z} X ➝ ^A {Z + 1} Y + β^-.
Beta Decay
The speed of electromagnetic waves traveling through a vacuum, given by the equation c = λf, where c is a constant equal to 3.00 × 10^8 m/s.
Speed of Light
States that the mass flow rate of fluid must remain constant from one cross-section of a tube to another, given by A{1}V{1} = A{2}V{2}.
Continuity Equation
The loudness of a sound, measured in decibels (dB) and denoted by β. Given by the equation β = 10log(I/I{0}), where I is the intensity of the sound and I{0} is a reference intensity of 10^‐12 W/m².
Sound Level
A vector quantity describing a change in velocity over the elapsed time during which that change occurs, expressed as a = Δv/Δt.
Acceleration
States that the change in internal energy of a system is equal to the heat transferred into the system minus the work done by the system: ΔU = Q - W. An extension of the law of conservation of energy.
First Law of Thermodynamics
A nuclear reaction in which high-energy photons, also known as γ-particles, are emitted: ^A {Z} X* ➝ ^A {Z} X + γ.
Gamma Decay
Ratio of the speed of light in a vacuum to the speed of light through a medium, given by: n = c/v.
Index of Refraction
The amount of electric potential energy per unit charge; the work required to bring a positive test charge q{0} from infinity to within an electric field of another positive charge, Q, divided by that test charge’s magnitude. Calculated by the equation V = kQ/r.
Electric Potential
The energy associated with stretching or compressing a spring, calculated by the equation U = 1/2kx² and given in the SI unit of joules (J).
Elastic Potential Energy
One of the two forms of energy transfer in which a force is applied to change the energy of a system. In mechanics, commonly calculated by the equation W = Fdcosθ, where F is the magnitude of the applied force, d is the magnitude of the displacement, and θ is the angle between these two vectors.
Work
The full range of frequencies and wavelengths for electromagnetic waves broken down into the following regions (in descending order of λ): radio, infrared, visible light, ultraviolet, X-ray, and gamma ray.
Electromagnetic Spectrum
The amount of time it takes for one-half of a radioactive sample to decay, given by the equation T{1/2} = ln(2)/λ, where λ is a decay constant.
Half-Life
Type of liquid flow that occurs when the linear flow speed in a tube exceeds the critical speed v{c}. The motion of the fluid that is not adjacent to the container walls is highly irregular, forming vortices and a high resistance.
Turbulent Flow
The force per unit area: P = F/A. May be provided as absolute (hydrostatic) pressure, which is the pressure below the surface of a fluid that depends on gravity and surface pressure, calculated by P = P{0} + ρgz, where P is absolute pressure, P{0} is the pressure at the surface, ρ is the density of the fluid, g is acceleration due to gravity, and z is depth.
Pressure
A vector quantity describing an object’s displacement over the elapsed time, expressed as v = Δx/Δt.
Velocity
The condition in which the incident angle of light traveling from a medium with a high n to a medium with a low n is greater than the critical angle θ{c}. This results in all of the light being reflected and none of it being refracted.
Total Internal Reflection
A force creating rotation about an axis; measured as the lever arm (the distance between the fulcrum and the applied force) times the magnitude of the force times the sine of the angle between them: τ = rFsinθ.
Torque
A dimensionless value denoted by m given by the equation: m = -i/o, where i is image distance and o is object distance. A negative m denotes an inverted image, whereas a positive m denotes an upright image.
Magnification
Intrinsic property of a conductor used to measure its resistance in the equation R = ρL/A, where R is the resistance, ρ is the resistivity, L is the length of the conductor, and A is its cross-sectional area.
Resistivity
States that when light waves strike a medium, the angle of incidence θ{i} is equal to the angle of reflection θ{r}.
Law of Reflection
A scalar quantity defined as mass per unit volume, often denoted by ρ. Density of an object may be compared to water as a unitless quantity known as specific gravity.
Density
A nuclear reaction in which an α-particle (^4 {2} He) is emitted: ^A {Z} X ➝ ^(A - 4) {Z - 2} Y + ^4 {2} He.
Alpha Decay
States that a body that is fully or partially immersed in a liquid will be buoyed upwards by a force that is equal to the weight of the liquid displaced by the body: F{buoy} = ρ{fluid}V{submerged}g.
Archimedes’ Principle
