Electrical Energy Vocabulary & Formulas

Flashcards covering vocabulary related to electrical energy and charging methods.

Electricity

The movement of electrons between atoms.

Electrical Energy

Energy generated from the movement of electrons from one point to another or the energy from electricity.

1 Wh

Equivalent to 3600 Ws (watt-seconds).

1 Ws

Equivalent to 1 Joule (J).

1 kJ

Equivalent to 1000 Joules (J).

Watt

Unit/measurement of power.

Watt-hour

Measurement of energy.

1 kWh

Equivalent to 1000 Watt-hours.

Electrical energy formula (E)

E = kW x h.

Efficiency

Measurement of how much energy is wasted when used, calculated as (output/input) x 100.

Electrical charge

Charged particles that exert an electric force on each other, where opposite charges attract and like charges repel.

Static electricity

Electric charge that tends to stay on the surface of an object, rather than flowing away quickly.

Insulators

Materials where electrons cannot move easily from one atom to another.

Conductors

Materials where electrons can move easily from one atom to another.

Grounding

The process of connecting a charged object to the Earth’s surface to act as an escape route for electrons.

Charging

The process of altering the charge of an object, where only electrons move; protons do not.

Method of Charging: Contact

A process where two objects touch, allowing charge to be transferred.

Method of Charging: Friction

A process where two neutral objects rub together, leading to a transfer of electrons.

Method of Charging: Induction

A process where a charged object comes close to a neutral object, resulting in a temporary charge without touching.

Electrostatic Series

A list of materials arranged according to their ability to hold onto electrons and predicts charges for charging by friction.

Coulomb's Law

States that the closer the objects, the stronger their electric force.

Step-up transformer

• increases voltage which reduces power loss

• used in second step of how we get electricity to our homes after the electric current is generated

Step-down transformer

• decreases the voltage making it safe enough for malls, factories and more

• used after high voltage transmission lines in something called substation

• also used again to reduce voltage further for safe use in homes

Meters

track the amount of electrical energy used in a home and is used by utility companies to charge you

Distribution Panel

distributes electricity through your home and contains circuit breakers and fuses

Examples of Insulators

hair, wood, rubber, plastic, gas, paper, and glass

Coulomb's Law

Tells us that the closer the objects, the stronger their electric force.

Current Electricity

Electricity that is always moving and flows through or to circuits.

Series Circuit

Has only one path along which electrons can flow.

Parallel Circuit

Has more than one path along which electrons flow.

Energy Source

Battery that has a negative and positive terminal.

Conductor

Wires that allow for electrons to flow.

Load

A resistor that converts electrical energy into something else, like a lightbulb or motor.

Terminal

Part of the cell/battery that is connected to the rest of the circuit.

Switch

Can break or close a circuit.

Resistor

A material that slows current flow.

Fuse

A safety feature that melts when exposed to dangerous current.

Circuit Breaker

Switch that automatically opens if the circuit is short circuiting or current is dangerous.

Ammeter

Measures the current in amperes.

Voltmeter

Measures the voltage in volts, always in parallel.

Current

Rate of movement of electric charge, measured in amperes.

Voltage

Stored energy, measured in volts.

Resistance

Stops/slows current, measured in OHMS.

Power

Rate at which work is done or the transfer of electrical energy within a circuit.

1 C

Equivalent to 6.24 X 10^18 electrons.

I = q/t

Formula where I is current, q is charge in coulombs, and t is time in seconds.

V = E/q

Formula where V is voltage, E is energy in Joules, and q is charge in coulombs.

R = V/I

Formula for resistance where R is resistance, V is voltage, and I is current.

P = VI

Formula for power where P is power, V is voltage, and I is current.

P = I^2R

Another formula for power in terms of current and resistance.

P = V^2/R

Formula for power in terms of voltage and resistance.

P = E/t

Formula where P is power, E is energy transferred in Joules, and t is time in seconds.

W = J/s

Watt is represented as 1 joule per second.

I

current

V

potential difference

R

resistance

Voltage in series

VT = V1 + V2 + ... + Vn; Add all the voltages

Resistance in Series

RT = R1 + R2 + ... + Rn; Add all the resistances

Voltage in Parallel

VT = V1 = V2 = ... = Vn; Voltage is the same

Adding bulbs in series circuit

Increases resistance and decreases brightness

Adding bulbs in parallel circuit

Decreases resistance and brightness doesn't change

When is the brightness of lighbulbs the same?

Same brightness IF they are the same (i.e. same resistance)

Different bulbs

Different bulbs = different brightness

Total Current in Parallel circuit

The sum of the currents at all points in a circuit.

Voltage across the source of a series circuit

The total voltage supplied by the source, calculated as VT = V1 + V2.

Resistance of bulbs

The resistance values of the bulbs in the circuit, assumed to be the same.

Current readings

The measurements of electric current at various points in the circuit.

GRASP

A problem-solving strategy that includes identifying what is known, what is being solved for, and how to solve it.

R1 = R2

Indicates that the resistance at point 1 is equal to the resistance at point 2.

Voltage in parallel circuit

Vt = V1 = V2

Resistance in parallel circuit

1/Rt=1/R1+1/R2+1/R3