Physics Examination Study Guide: Electricity, Magnetism, and Thermal Energy

These flashcards provide a comprehensive review of electricity, circuits, magnetism, and thermal energy concepts based on the physics examination study guide.

Electricity

A form of energy resulting from the existence of charged particles (such as electrons or protons), either statically as an accumulation of charge or dynamically as a flow of electrons.

Electric Current

Produced by the movement of electrons from a negative (−) pole to a positive (+) pole.

Filament

A small coiled wire that glows when electric current passes through it.

Circuit

A closed, never-ending loop of conductive material required for current electricity to flow.

Connecting wire

A component used to conduct or pass current from one part of a circuit to another.

(Single) Cell

Supplies electrical energy; the larger terminal indicates the positive (+) end, while the shorter terminal is the negative (−) end.

Battery

Two or more cells joined together to supply electrical energy.

Open Switch (OFF)

Used to break electrical circuits by making an insulating gap, preventing continuous current flow.

Resistor

Slows down the flow of electrons in a circuit, thus limiting electric current.

Ammeter

Measures the flow of electrons in a circuit in Amperes ($A$) or amps; must always be connected in series.

Voltmeter

Measures the voltage or potential difference produced by a power supply in Volts ($V$); must be connected in parallel.

Fuse

A safety device which will "blow" or melt if the current flowing through it exceeds a specified value.

Direct Current (DC)

Electric charge flows only in one direction, from negative to positive.

Alternating Current (AC)

Electric charge changes direction periodically, causing the voltage to also periodically reverse.

Conventional Current Flow

The conceptual behavior as if positive charge carriers flow from the positive (+) terminal to the negative (−) terminal.

Actual (Electron) Flow

The physical movement of electrons from the negative (−) terminal to the positive (+) terminal.

Ampere

A unit of measurement representing a flow of about 6 million million million electrons per second past a single point.

Ohm's Law (1826)

The principle that the current flowing through a metal wire is proportional to the potential difference across it, provided the temperature remains constant.

Resistance Calculation (Series)

The total resistance ($R_t$) is the sum of all individual resistances: $R_t = R_1 + R_2 + R_3 + \text{...}$

Resistance Calculation (Parallel)

The total resistance is calculated as: $\frac{1}{R_t} = \frac{1}{R_1} + \frac{1}{R_2} + \frac{1}{R_3} + \text{...}$

Ohm's Law Relation

The mathematical relationship expressed as: $I = \frac{V}{R_t}$

One-way switch

A device that turns a single circuit on or off.

Two-way switch

Allows a circuit to be switched on or off from two different locations, such as the top and bottom of a staircase.

Static Electricity

Uncontrolled, stationary electric charges passing from one body to another in sudden, momentary movements.

Current Electricity

Controlled electrons moving systematically along a path in one specific direction, characterized by continuous flow and electrical pressure.

Magnetism

A physical phenomenon produced by the motion of electric charge, resulting in attractive and repulsive forces between objects.

Magnet

A piece of iron or other material with ordered component atoms that attracts iron-containing objects or aligns within an external magnetic field.

Magnetic Poles

The two ends of a magnet, North ($N$) and South ($S$); unlike poles attract, and like poles repel.

Magnetic Field

A region around a magnetic material or moving electric charge within which the force of magnetism acts.

Ferromagnetic Materials

Metals that can be magnetized; when held close to a strong magnet, an electrical field is induced causing the object to become temporary magnetic.

Permanent Magnets

Magnets that retain magnetic properties for long periods, such as those made from steel.

Temporary Magnets

Materials like iron that lose induced magnetism quickly once removed from a magnetic field.

Declination

The slight skew between the Earth's magnetic field axis and its rotational axis.

Magnetosphere

The magnetic force field extending out into space that acts as a shield protecting Earth from harmful solar gases and charged particles.

Magnetic Shielding

A process that limits magnetic coupling by re-routing field lines around an object using materials with high magnetic permeability.

Heat

A form of energy measured in Joules ($J$) that moves from a warmer region to a cooler region due to a temperature gradient.

Temperature

A measure of the specific amount of heat a particular body possesses, with the SI unit Kelvin ($K$).

Kelvin Conversion Formula

The formula to convert Celsius to Kelvin: $K = \text{}^\text{\textdegree}C + 273$

Thermal Equilibrium

The state where objects reach equal temperatures and thermal exchange ceases.

Conduction

The process of vibrational energy transfer between adjacent particles; it is the main heat transfer process in solids.

Convection

Density-driven mass movement within fluids (liquids and gases) where heated fluids expand, become less dense, and rise.

Radiation

Heat transfer via electromagnetic infrared waves that can travel across a vacuum at the speed of light.

Matte (Dull and Dark) Surfaces

The best absorbers and the best emitters of heat radiation.

Light and Shiny Surfaces

The poorest absorbers and poorest emitters of heat radiation, acting as excellent reflectors.

Thermal Insulator

A material that conducts heat poorly; examples include wood, plastics, ceramics, and trapped gases like air.

Vacuum Flask (Thermos)

An engineering application designed to minimize conduction, convection, and radiation to maintain the temperature of its contents.