Electricity and Magnetism Review

Test Monday

The Nature of Magnetism

Magnetism

Magnetism is the attraction of a magnet for another object.

Poles

Magnets are strongest at the poles

The north pole repels the other north poles but attracts the south poles.

Magnetic Fields

The area of Force around a magnet is know as magnetic Fields.

Magnets

Opposites attract while similar poles repel.

Magnetic Domains

In a magnetic material most of the clusters of billions of atoms, or magnetic domains, have magnetic fields that are lined up in the same way.

Magnetic Domains- clusters of billions of atoms that have a magnetic field that are lined up parallel in the same way.

Magnets being ruined or dropped

If you heat or drop a magnet they can be ruined.

When a permanent magnet is dropped and cracks into a half it creates 2 new magnets.

The Earth as a Magnet

The Earth and Compasses

The earth acts like a giant magnet with 2 poles and a giant magnetic field.

A compass is a device that has a freely spinning magnetized needle.

Magnetic Declination

Magnetic Declination is the angle between geographic and magnetic poles from where you are on the earth.

Current Electricity and Circuits

Current

Current is the flow of charge or electrons through a material.

An electric current produces a magnetic field.

Three Types of Particles

Protons- found in nucleus/the charge is positive (+)

Neutrons- found in nucleus/the charge is neutral

Electrons- found outside the nucleus/ the charge is negative (-)

3 Parts of a Circuit

Source- a battery

Resistor/Device- a light bulb

Path- a wire

Types of Circuits

Series have 1 path-1 goes out all goes out, more bulbs=dimmer

Parallel have multiple paths- 1 goes out all stay on, more bulbs= nothing happens

Voltage

Voltage is another name for potential difference

Voltage causes the current to flow

Voltage is measured in Volts or (V)

Current

Current is measured in Amps or (A)

Resistance

Resistance is measured in Ohm’s or (Ω)

Ohm’s=volts/amps

Resistance= volts/current

Different Signs

Volts-(V)

Amps-(A)

Ohm’s-(Ω)

Static Electricity

Static Electricity

Static Electricity is the build up of charges on an object

Repel and Attracts

Just like magnetism opposites attract and the similar repels.

How Charges are TransferredFriction- charges transfer when objects rub against each other

Conduction- charges transfer by direct contact

Induction- charges are rearranged or moved in one object while another is brought near

Static Discharge

Static Discharge is the loss of static electricity moving from 1 thing to another

The Law of Conservation of Charge

The Law of Conservation of Charge states that change can’t be made or destroyed.

Materials

Conduction

Conduction are materials that allow electrons to flow freely through them.

Some examples are metals, copper, iron, and water.

Insulators

Insulators are materials that hold on to their electrons, not allowing current to pass though well.

Some examples are rubber, glass, plastic, and wood.

Electromagnets

Solenoid

A solenoid is a current carrying wire surrounding an iron core.

Electromagnets

Electromagnets are useful because they can be turned on and off.

The Strength of an Electromagnet

The strength of an electromagnet can be increased by the number of loops, increasing the current, and having a stronger core.