Electricity, Magnetism, and Circuits: Key Concepts for Physics

What is electricity?

The flow of electrons

What are electrons?

Negatively charged particles

What is current?

The flow of electric charges

What causes electrons to move?

Energy (voltage)

What is static electricity?

Buildup of charges in one place

How can charge be transferred?

Conduction (touching)

What do like charges do?

Repel

What do opposite charges do?

Attract

What law describes electric force?

Coulomb's Law

What happens to force when distance decreases?

Force increases

What is electric potential difference?

The push that moves charges

What is another name for electric potential difference?

Voltage

What unit is voltage measured in?

Volts

What is grounding?

Charges flow into the Earth safely

What is current electricity?

Moving charges through a circuit

What must a circuit have?

Energy source, closed path, device

What is a closed circuit?

A complete path for current

What is an open circuit?

A broken path (no current flows)

What is a series circuit?

One path for current

What happens if one part breaks in a series circuit?

Everything stops

How do you find total resistance in series?

Add all resistances

What is a parallel circuit?

Multiple paths for current

What happens if one branch breaks in parallel?

Others still work

How is resistance different in parallel circuits?

Lower total resistance

What is power?

The rate of energy transfer

What unit is power measured in?

Watts

What is the formula for power?

P = IV

What is resistance?

Opposition to current flow

What unit is resistance measured in?

Ohms

What law relates voltage, current, and resistance?

Ohm's Law

What is Ohm's Law formula?

V = IR

What happens to current if resistance increases?

Current decreases

What happens to current if voltage increases?

Current increases

What are fuses and circuit breakers used for?

Stopping excessive current

What is a short circuit?

When electricity takes an easier path

What are magnets?

Objects with north and south poles

What are the poles of a magnet?

North and South

What happens with like magnetic poles?

Repel

What happens with opposite magnetic poles?

Attract

What is a magnetic field?

Area where magnetic force exists

What shape are magnetic field lines?

Closed loops

What happens when current flows in a wire?

Creates a magnetic field

What is an electromagnet?

A magnet made using electricity

How can you strengthen an electromagnet?

Add coils or an iron core

What is a generator?

A device that creates electricity from motion

What must happen in a generator?

Motion between a magnet and wire

How do fossil fuels generate electricity?

Heat water to make steam that spins a turbine

How does nuclear energy generate electricity?

Heat creates steam that spins a turbine

How does wind generate electricity?

Spins turbine blades

How do hydroelectric dams generate electricity?

Falling water spins a turbine

What is a step-up transformer?

Increases voltage

What is a step-down transformer?

Decreases voltage

What voltage do homes typically use?

About 120 volts