AP Physics 2 Review

Flashcards for AP Physics 2 review, covering Thermodynamics, Electricity, Magnetism, Waves, Sound, Light, and Modern Physics.

Thermodynamics

The study of energy, heat, and work, and the transformations between them. It is governed by the laws of thermodynamics, which describe the behavior of energy at the macroscopic level, especially in the context of systems in equilibrium or undergoing changes.

Temperature

A measure of the average kinetic energy of the atoms or molecules within a system. In thermodynamics, temperature is crucial for determining the direction of heat flow and is measured in Kelvin (K), Celsius (°C), or Fahrenheit (°F).

Heat

Thermal energy transferred between objects or systems due to a temperature difference. Heat is not a state function; it depends on the path taken during a process and is measured in Joules (J).

Kelvin

The SI base unit of temperature, defined such that absolute zero (the point at which all molecular motion ceases) is 0 K. The Kelvin scale is used extensively in thermodynamics as it avoids negative temperatures.

Fahrenheit

A temperature scale where water freezes at 32 °F and boils at 212 °F. It is commonly used in the United States but less so in scientific contexts.

Celsius

A temperature scale where water freezes at 0 °C and boils at 100 °C. It is widely used in scientific measurements and everyday contexts outside the United States. T{\degree C} = TK - 273.15

Joule

The SI unit of energy, defined as the amount of work done when a force of one Newton displaces an object one meter in the direction of the force. In thermodynamics, it is used to measure heat, work, and internal energy.

Radiation

The process by which energy is emitted as electromagnetic waves or particles. In thermodynamics, radiation is a significant mechanism for heat transfer, especially in scenarios involving objects at high temperatures or in a vacuum.

Conduction

The transfer of heat through a substance via direct contact between particles. It occurs when a temperature gradient exists within a material, and the rate of heat transfer depends on the material's thermal conductivity.

Convection

The transfer of heat through the movement of fluids (liquids or gases). It involves the bulk motion of heated fluid away from a heat source, carrying energy with it.

Thermal Conductivity

A material property that indicates its ability to conduct heat. It is defined as the rate of heat transfer through a unit thickness of the material per unit temperature difference. Materials with high thermal conductivity are good heat conductors.

Heat Flow

The rate at which heat energy is transferred from one object or system to another, typically driven by a temperature difference. It is quantified as the amount of heat transferred per unit time and is influenced by factors like thermal conductivity and temperature gradient.

Internal Energy

The total energy contained within a thermodynamic system, including kinetic and potential energy of its constituent particles. Internal energy is a state function, meaning it depends only on the current state of the system, not on how that state was reached.

Phase Change

The transformation of matter from one state (solid, liquid, gas, or plasma) to another, accompanied by changes in internal energy. Phase changes occur at constant temperature and pressure and involve the absorption or release of latent heat.

Latent Heat

The heat absorbed or released during a phase change at constant temperature and pressure. It does not result in a temperature change but instead goes into changing the potential energy of the molecules.

Latent Heat of Fusion

The amount of heat required to change a substance from a solid to a liquid at its melting point without changing its temperature. It overcomes the intermolecular forces holding the solid structure together.

Condensation

The phase change of a gas or vapor to a liquid, typically occurring when the gas is cooled to its dew point or when its partial pressure increases to its saturation vapor pressure. It releases latent heat.

Vaporization

The phase change of a liquid to a gas or vapor, occurring when the liquid is heated to its boiling point or when its vapor pressure equals the surrounding pressure. It requires the input of latent heat to overcome intermolecular forces.

Boiling Point

The temperature at which the vapor pressure of a liquid equals the surrounding pressure, causing the liquid to rapidly vaporize. It depends on the intermolecular forces within the liquid and the external pressure.

Melting Point

The temperature at which a solid changes to a liquid at a given pressure. At this temperature, the solid and liquid phases are in equilibrium, and the addition of heat results in phase change rather than a temperature increase.

Liquid Water Turns to Ice

The phase change from liquid water to solid ice, occurring at 0 °C (32 °F) under standard atmospheric pressure. This process releases energy in the form of latent heat of fusion.

Specific Heat Capacity

The amount of heat required to raise the temperature of 1 gram (or 1 kg in SI units) of a substance by 1 degree Celsius (or 1 Kelvin) without undergoing a phase change. It is a material property that reflects how much energy is needed to change its temperature. Q = mc\Delta T, where Q is the heat added, m is the mass, and \Delta T is the temperature change.

Heat Pump

A device that transfers heat from a cold reservoir to a hot reservoir, requiring external work to operate. It works against the natural direction of heat flow and is commonly used for heating and cooling buildings.

Thermal Expansion

The tendency of matter to change in volume in response to changes in temperature. When a substance is heated, its particles move more and thus maintain a greater average separation. Linear expansion is given by: \Delta L = \alpha L0 \Delta T, where \alpha is the coefficient of linear expansion, L0 is the original length, and \Delta T is the temperature change.

Heat Engine

A device that converts thermal energy into mechanical work. According to the second law of thermodynamics, no heat engine can be perfectly efficient; some heat must be exhausted to a cold reservoir. Efficency e = \frac{W}{QH} = 1 - \frac{QC}{QH}, where W is the work done, QH is the heat from the hot reservoir, and Q_C is the heat exhausted to the cold reservoir.

PV Diagram

A graph of pressure vs. volume for a thermodynamic process, used to visualize the changes in a system's state. The area under the curve represents the work done by or on the system during the process.

Adiabatic Process

A thermodynamic process in which no heat is exchanged between the system and its surroundings (Q = 0). This typically occurs when the process happens quickly, not allowing time for heat transfer. In an adiabatic process, PV^\gamma is constant, where \gamma is the ratio of specific heats.

Isothermal Process

A thermodynamic process that occurs at constant temperature (\Delta T = 0). In an isothermal process, the heat added to the system equals the work done by the system, and the internal energy remains constant.

Isobaric Process

A thermodynamic process that occurs at constant pressure (\Delta P = 0). The work done in an isobaric process is given by W = P\Delta V, where \Delta V is the change in volume.

Isovolumetric (Isochoric) Process

A thermodynamic process that occurs at constant volume (\Delta V = 0). Since the volume does not change, no work is done by or on the system in an isovolumetric process (W = 0).

Zeroth Law of Thermodynamics

If two systems are each in thermal equilibrium with a third system, then they are in thermal equilibrium with each other. This law establishes temperature as a state function and allows for the definition of temperature scales.

First Law of Thermodynamics

The change in internal energy (\Delta U) of a system is equal to the heat added to the system (Q) minus the work done by the system (W): \Delta U = Q - W. This law is a statement of energy conservation.

Second Law of Thermodynamics

The entropy (S) of an isolated system never decreases; it either stays the same (for reversible processes) or increases (for irreversible processes). This law implies that natural processes tend to increase disorder.

Greenhouse Effect

The trapping of the sun's warmth in a planet's lower atmosphere due to the greater transparency of the atmosphere to visible radiation from the sun than to infrared radiation emitted from the planet's surface. Greenhouse gases like carbon dioxide and methane absorb and re-emit infrared radiation, warming the surface.

Entropy

A measure of the disorder or randomness of a system. In thermodynamics, entropy is related to the number of possible microstates corresponding to a given macrostate. The change in entropy (\Delta S) is given by: \Delta S = \frac{Q}{T}, where Q is the heat added reversibly, and T is the absolute temperature.

Charge

A fundamental property of matter that can be positive or negative. Electric charge is quantized, meaning it exists in discrete units (multiples of the elementary charge, e \approx 1.602 \times 10^{-19} Coulombs).

Coulombs

The SI unit of electric charge, defined as the amount of charge transported by a current of one ampere in one second. Symbol: C.

Ampere

The SI unit of electric current, defined as the flow of one coulomb of charge per second. Symbol: A.

Volt

The SI unit of electric potential difference, defined as the potential difference between two points when one joule of work is required to move one coulomb of charge between them. Symbol: V.

Ohm

The SI unit of electrical resistance, defined as the resistance between two points in a conductor when a potential difference of one volt applied between these points produces a current of one ampere. Symbol: \Omega.

Watt

The SI unit of power, defined as one joule per second. In electrical contexts, power is the product of voltage and current (P = VI). Symbol: W.

Current

The rate of flow of electric charge through a conductor, measured in amperes (A). Current is defined as the amount of charge passing through a cross-sectional area per unit time: I = \frac{dQ}{dt}, where I is the current, Q is the charge, and t is the time.

Charging by Conduction

The process of charging an object by bringing it into direct contact with a charged object. During conduction, charge is transferred between the objects until they reach the same electric potential.

Charging by Induction

The process of charging an object without direct contact by bringing a charged object nearby. This causes a redistribution of charge within the neutral object, which can then be grounded to create a net charge.

Electrostatics

The branch of physics that deals with electric charges at rest. It involves the study of electric fields, electric potentials, and forces between static charges.

Electrostatic Equilibrium

A condition in which there is no net flow of electric charge within a conductor. In electrostatic equilibrium, the electric field inside the conductor is zero, and any excess charge resides on the surface.

Faraday's Ice Pail Experiment

A demonstration by Michael Faraday that shows that charge resides on the surface of a conductor. When a charged object is placed inside a hollow conductor (ice pail), the charge induced on the inner surface is equal in magnitude and opposite in sign to the charge on the object.

Millikan's Oil Drop Experiment

An experiment conducted by Robert Millikan that determined the elementary charge (e) of an electron. By balancing the electric force on charged oil droplets with the gravitational force, Millikan was able to measure the charge on the droplets.

Insulator

A material that does not allow electric charge to flow easily due to its high electrical resistance. Examples include rubber, glass, and plastic.

Conductor

A material that allows electric charge to flow easily due to its low electrical resistance. Examples include metals like copper, aluminum, and silver.

Direct Current

Electric current that flows in one direction only. It is commonly produced by batteries and DC power supplies.

Alternating Current

Electric current that periodically reverses direction. It is commonly used in household electricity and is described by a sinusoidal function.

Circuit

A closed loop through which electric current can flow. It consists of a voltage source, conductors, and components like resistors, capacitors, and inductors.

Circuit Diagram

A diagram that shows the components of an electric circuit using standard symbols. It is used to analyze and design electrical circuits.

Resistor

A component that opposes the flow of electric current, dissipating energy as heat. The resistance (R) is measured in ohms (\Omega).

Capacitor

A component that stores electric charge, consisting of two conductive plates separated by an insulating material (dielectric). The capacitance (C) is measured in farads (F).

Battery

A device consisting of one or more electrochemical cells that convert stored chemical energy into electrical energy. It provides a direct current (DC) voltage source.

Voltage Source

A device that provides a constant voltage or electric potential difference in a circuit. It can be a battery, power supply, or generator.

Emf

Electromotive force; the voltage provided by a battery or voltage source. It represents the energy per unit charge supplied by the source.

Coulomb's Law

The force between two electric charges is proportional to the product of the charges and inversely proportional to the square of the distance between them: F = k \frac{|q1 q2|}{r^2}, where F is the force, q1 and q2 are the charges, r is the distance, and k is Coulomb's constant (\approx 8.99 \times 10^9 Nm^2/C^2).

Ohm's Law

The voltage across a resistor is proportional to the current through the resistor: V = IR, where V is the voltage, I is the current, and R is the resistance.

Kirchoff's Loop Rule

The sum of the voltage drops around a closed loop in a circuit is zero, which is a statement of energy conservation: \sum V = 0. It implies that the total potential rise equals the total potential drop in a closed loop.

Series Circuit

A circuit in which the components are connected in a single path, so the same current flows through each component. The total resistance is the sum of individual resistances: R{total} = R1 + R_2 + …

Parallel Circuit

A circuit in which the components are connected in multiple paths, so the voltage across each component is the same. The reciprocal of the total resistance is the sum of the reciprocals of individual resistances: \frac{1}{R{total}} = \frac{1}{R1} + \frac{1}{R_2} + …

Electric Potential Difference

The difference in electric potential between two points, measured in volts (V). It represents the work done per unit charge to move a charge between the two points: V = \frac{W}{q}, where V is the potential difference, W is the work done, and q is the charge.

Electric Potential Energy

The energy required to move a charge through an electric field. It is the product of the charge and the electric potential: U = qV, where U is the potential energy, q is the charge, and V is the electric potential.

Electric Field

A region of space around an electric charge in which another charge would experience a force. It is a vector field, with the direction of the field being the direction of the force on a positive test charge. E = \frac{F}{q}, where E is the electric field, F is the force, and q is the charge.

Resistors in Series

Resistors connected in a single path such that the same current flows through each resistor. The equivalent resistance is the sum of individual resistances: R{eq} = R1 + R_2 + …

Resistors in Parallel

Resistors connected in multiple paths such that the voltage across each resistor is the same. The reciprocal of the equivalent resistance is the sum of the reciprocals of individual resistances: \frac{1}{R{eq}} = \frac{1}{R1} + \frac{1}{R_2} + …

Capacitors in Series

Capacitors connected in a single path such that the charge on each capacitor is the same. The reciprocal of the equivalent capacitance is the sum of the reciprocals of individual capacitances: \frac{1}{C{eq}} = \frac{1}{C1} + \frac{1}{C_2} + …

Capacitors in Parallel

Capacitors connected in multiple paths such that the voltage across each capacitor is the same. The equivalent capacitance is the sum of individual capacitances: C{eq} = C1 + C_2 + …

Electric Field Lines

Lines that represent the direction and strength of an electric field. They originate from positive charges and terminate on negative charges, with the density of the lines indicating the strength of the field.

Electric Flux

A measure of the electric field passing through a surface, given by the dot product of the electric field and the area vector: \PhiE = \int E \cdot dA, where \PhiE is the electric flux, E is the electric field, and dA is the differential area vector.

Van de Graaff Generator

An electrostatic generator that uses a moving belt to accumulate electric charge on a hollow metal globe. It is used to create high voltages for experiments in electrostatics and particle acceleration.

Gauss's Law

The electric flux through a closed surface is proportional to the charge enclosed by the surface: \oint E \cdot dA = \frac{Q{enc}}{\epsilon0}, where E is the electric field, dA is the differential area vector, Q{enc} is the enclosed charge, and \epsilon0 is the vacuum permittivity.

Electron Volts

A unit of energy equal to the energy gained by an electron when it moves through a potential difference of 1 volt (1 eV = 1.602 \times 10^{-19} J). It is commonly used in atomic and nuclear physics.

Energy Stored in a Capacitor

The energy stored in the electric field of the capacitor, given by: U = \frac{1}{2}CV^2 = \frac{1}{2}QV = \frac{Q^2}{2C}, where U is the energy, C is the capacitance, V is the voltage, and Q is the charge.

Dielectric

An insulating material placed between the plates of a capacitor to increase its capacitance. It reduces the electric field and allows for greater charge storage at a given voltage.

Open Circuit

A circuit in which there is a break in the path, preventing current from flowing. The resistance is effectively infinite.

Closed Circuit

A circuit in which there is a complete path, allowing current to flow. The resistance is finite and non-zero.

Short Circuit

A circuit in which there is a low-resistance path, causing a large current to flow. It can lead to overheating and damage to components.

Ammeter

A device used to measure electric current in a circuit. It is connected in series with the circuit to measure the current flowing through it.

Voltmeter

A device used to measure electric potential difference between two points in a circuit. It is connected in parallel with the component across which the voltage is to be measured.

Resistivity

A measure of a material's opposition to the flow of electric current, independent of its geometry. It is defined as: \rho = \frac{RA}{L}, where \rho is the resistivity, R is the resistance, A is the cross-sectional area, and L is the length.

Power

The rate at which energy is transferred or consumed in a circuit, measured in watts (W). It is given by: P = VI = I^2R = \frac{V^2}{R}, where P is the power, V is the voltage, I is the current, and R is the resistance.

Brightness of a Lightbulb

The amount of light emitted by a lightbulb, which is proportional to the power dissipated by the bulb. Brighter bulbs consume more power.

Neodymium Magnet

A strong permanent magnet made from an alloy of neodymium, iron, and boron. It is used in various applications, including motors, speakers, and magnetic resonance imaging (MRI).

Magnetic Poles

The points on a magnet where the magnetic field is strongest, labeled as North (N) and South (S). Like poles repel, and opposite poles attract.

Electromagnet

A magnet made by passing an electric current through a coil of wire. The strength of the magnetic field is proportional to the current and the number of turns in the coil.

Magnetic Field

A region of space around a magnet or moving electric charge in which a magnetic force acts. It is a vector field, with the direction of the field being the direction of the force on a positive moving charge. Symbol: B.

Tesla

SI unit of magnetic field strength, defined as one Newton per Ampere per meter (1 T = 1 N/Am). It is a measure of the force experienced by a moving charge in a magnetic field.

Induced Magnetism

The process by which a material becomes magnetized when placed in a magnetic field. Certain materials align their magnetic domains with the external field, becoming temporarily or permanently magnetized.

Right Hand Rule

A mnemonic used to determine the direction of the magnetic force on a moving charge or current-carrying wire in a magnetic field. There are several versions, including using the right hand to align with the velocity and magnetic field to find the force direction.

Magnetic Force

The force exerted on a moving electric charge in a magnetic field, given by: F = qvB\sin\theta, where F is the force, q is the charge, v is the velocity, B is the magnetic field strength, and \theta is the angle between v and B. The direction of the force is given by the right-hand rule.

Induced Current

The creation of a current in a circuit due to a changing magnetic field, as described by Faraday's law of induction. The magnitude of the induced emf is proportional to the rate of change of magnetic flux.

Magnetic Flux

A measure of the magnetic field passing through a surface, given by: \PhiB = \int B \cdot dA, where \PhiB is the magnetic flux, B is the magnetic field, and dA is the differential area vector.

Electric Motor

A device that converts electrical energy into mechanical energy using magnetic forces. It operates on the principle that a current-carrying wire in a magnetic field experiences a force, causing rotation.

Electric Speaker

A device that converts electrical energy into sound energy using magnetic forces. It uses a current-carrying coil in a magnetic field to vibrate a diaphragm, producing sound waves.

Generator

A device that converts mechanical energy into electrical energy using magnetic induction. It operates on the principle that a changing magnetic field induces a current in a coil of wire.

Retarding Force

A force that opposes motion, causing an object to slow down. Examples include friction, air resistance, and viscous drag.