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Like charges

repel

Opposite charges

attract

Neutral objects

are attracted by charged objects

Grounding

A charged object becomes neutralized when touched with a conductor, allowing electrons to flow in or out.

Charging by induction

A charged object polarizes a neutral conductor without touching it, and then the polarized object is touched with a ground to become charged.

Charging by friction

Physical contact with an insulator through rubbing fast.

Coulomb's Law

Typically, distance is more important because it is an exponential relationship.

Conductors

Allow electrons to move easily; examples include metals, salt water (with ions).

Insulators

Prevent electrons from moving; can be charged; examples include gases, plastics, glass.

Direct Current

Current that runs from one end of the battery to the other, through the circuit.

Alternating Current

Electrons move in place from side to side; good for high voltage.

Voltage

The electrical potential energy that makes charge move; unit is volts.

Resistance

The measure of how much energy is taken up; unit is Ohm.

Current

The rate of electrons passing through a certain amount of time; unit is Ampere or Amps.

Ohm's Law

V = I X R; Voltage equals current multiplied by resistance.

Kirchhoff's Current Law

The amount of current that enters the system stays the same.

Kirchhoff's Voltage Law

All the voltage that enters the system must be used up.

Complex circuit

A combination of a series and parallel circuit.

DC (Direct Current)

Used for short distances; found in battery powered or rechargeable devices.

AC (Alternating Current)

Used for long distances; like transmission power lines.

Conventional flow

Electricity was thought to flow from positive to negative before the discovery of electrons.

Actual movement of electrons

Electrons move from the negative side to the positive side.

Three resistors in series

Each resistor has a resistance of 1.5 Ohms.

Resistance of a resistor

Each resistor has a resistance of 1.5 Ohms.

Total resistance in a series circuit

Kirchoff's resistor rules - add up the resistors, it equals the total resistance in a series circuit. 4.5 Ohms.

Power used by a light bulb

Power in Watts = Current X voltage; 2 amps x 3V = 6 Watts.

Current calculation

What is the current if the resistance of the filament of the bulb is 2 ohms and the voltage used is 8 Volts?

Levels of magnetism

The four levels of magnetism are Particle (quantum level - electrons have a tiny magnetic moment), Atomic (electrons spin around atom), Crystal (groups of Atoms), and Domains (groups of groups of atoms).

Common magnetic rocks

Hematite, magnetite, lodestone.

Visual evidence of Earth's magnetosphere

Aurora Borealis - Northern Lights.

Impact of distance from pole on magnetic field strength

Yes, where it is placed in the magnetic field changes how it interacts - force acting on it.

Animals using magnetic fields for navigation

Examples: Lobsters, Pigeons, specific species of bacteria.

Quantum particle associated with magnetism

Electron - tiny magnetic moment.

Ways to create a magnet

Run a current through a wire, heat up a chunk of metal in a magnetic field (or run a current through it), rub a piece of metal with other magnets consistently enough.

Difference between Earth's geographic and magnetic north pole

The Earth's geographic north pole is the Earth's magnetic south pole - since opposite poles attract.

Basic function of a motor

The basic function of a motor is to turn electrical energy into mechanical energy.

Basic function of a generator

The basic function of a generator is to turn mechanical or kinetic energy into electrical energy.

Michael Faraday

Michael Faraday figured out that electricity and magnetism were linked. He invented the motor.

Challenges faced by Michael Faraday

He was a part of a religious minority, grew up poor and uneducated, and his mentor, Humphery Davey, betrayed him by accusing him of plagiarism.

Faraday's Law

Faraday's law explains that a moving/changing magnetic field (magnetic flux) creates electron flow/current in a conductor.

Magnetic flux calculation

How do you calculate magnetic flux?

EMF calculation

How do you calculate emf? What variables do you change to make it bigger? What variables do you change to make it smaller?

Variables affecting EMF size

You can make it smaller by increasing the amount of time it takes to change direction, decrease the number of loops, and decrease the changing magnetic flux. You can make it bigger by increasing the number of loops in the wire, increase the changing magnetic flux, and decrease the amount of time it takes for it to change.

Right hand rule example

An electric current moving upward through a straight wire creates a magnetic field. If the current is going up, the magnetic field runs counter clockwise.

Ways to demagnetize a permanent magnet

Drop it and realign the domains, heat it up, run a current through it the opposite way the magnetic fields align.

Creating an electromagnet

Wrap a coil of wire around an iron core (usually a steel nail) and run a current through it/hook up a battery.

Parts of a DC motor

What are the four parts of the DC motor and what do they do?

Armature

spinning electromagnet- typically connected to the rotor

Commutator

connects to the brushes, helps change the direction of the current

Stator

permanent magnets, typically placed around the armature

Rotor

provides spinning motion to get mechanical work done.

Hydroelectric power plants

water spins turbine, rotating electromagnet around permanent magnets

Coal fire power plants

burning coal makes steam, steam spins turbine

Nuclear power plants

fission reactions heat up water, steam turns turbine.

Magnetic flux formula

Stronger magnetic field, more area of the magnetic field.

Magnetic induction formula

More Flux! Faster movement.

Wavelength

the distance it takes for the wave cycle to repeat itself (m)

Frequency

how many cycles per unit of time, (Hz) usually cycles or # of waves per second

Period

how much time it takes to complete one cycle (s)

Crests

the top or the peak of the wave

Amplitude

the distance measure from the midpoint to the top of the wave- Indicator of energy

Troughs

the bottom scoop of the wave

Nodes

mid points of the wave- points of no displacement.

Antinodes

tops of peaks and troughs, points of maximum displacement

Decibels

logarithmic scale, exponential base 10 that shows comparatively how loud a noise is.

Pitch

musical term for a frequency of sound.

Rhythm

pattern of sound- not a test question

Speed of sound calculation

Frequency X wavelength

Sound travel speed

the denser material the faster the sound, because the closer the molecules are to each other- the less lag time.

Hearing process

Eardrum vibrates which send signals to the bones of the inner ear (hammer stirrup and anvil, which send signals to the cochlea, which makes hair cells vibrate which send signals to the hearing nerve.

Transverse wave

a transverse wave has a displacement perpendicular to the motion of wave travel

Longitudinal wave

a longitudinal has a displacement parallel to wave travel

Electromagnetic spectrum waves

Electricity and magnetism 90 degrees out of phase with each other.

Waves transmit

Energy

Microwaves cooking food

Microwaves vibrate water molecules by emitting a certain frequency of the electromagnetic spectrum from the magnetron.

Reflection

bounces back- like in an echo or a mirror

Refraction

bends, still goes through the material, mermaid singing, prism

Diffraction

wave bend around material

Absorption

energy goes into the material and the wave's energy gets dissipated into nothingness.

Light as a particle evidence

The photoelectric effect, traveling through a vacuum

Light as a wave evidence

Young's Double slit experiment-wave interference

Electromagnetic spectrum in universe

Radio telescopes gather information on objects that can't be seen with visible light- like pulsars and black holes.

InfraRed telescopes

can help identify extrasolar planets that don't give off visible light.

Everyday use of electromagnetic spectrum

Remote control cars, Microwaves, Walkie talkies, cell phones, wireless internet, radio stations.

Electromagnetic spectrum order

Radio waves, microwaves, infrared, visible light, ultraviolet, X rays, Gamma rays.

Electromagnetic spectrum speed

Yes. It slows down through light and water.