Electromagnetism and Generating Electricity

Electricity and Magnetism Electricity and

magnetism are different aspects of a single force: electromagnetism Electricity = result

of charged particles Magnetism = result

of moving electrons in an atom

Electricity and Magnetism Moving electric

charge creates a magnetic field. Magnetic field

lines form circles around wire

Right hand rule

Electricity and Magnetism Solenoid – a coil of wire with an electric

current (produces magnetic field). By putting a solenoid around an magnetic

metal, you create an electromagnet.

Solenoid makes an electromagnet

Electricity and Magnetism Strength of electromagnet depends on

1. Current 2. Number of loops3. Type of core

Electromagnetic Devices

Many devices use electromagnets: 1. Galvanometer – device that detects

and measures electric current2. Electric motor – uses an

electromagnet to turn an axle.3. Loudspeaker – uses changing

current to move a magnet back and force to produce sound waves

Electric Motor

Generating Electricity

Moving a magnet into and out of a coil of wire causes charges in a wire to move. Electromagnetic induction – process of

creating a current by changing a magnetic field

Generating Electricity

Moving a magnet into and out of a coil of wire causes charges in a wire to move. Became Faraday’s Law Obeys conservation of energy

Generating Electricity

Generators are the opposite of motors: convert mechanical energy into electrical energy. Have wire loops that are rotated

between two magnets Can be either AC or DC

Generating Electricity

Transformer – device that increases or decreases the voltage of AC. Consists of two coils of wire wrapped

around opposite sides of a closed iron loop

One side has more loops More loops = greater voltage Used to transfer electricity (power plant

to homes)

Transformer

Electromagnetism Foldable Fold the paper as instructed Label each section as follows: For each section, draw the correct

figure from the book, including labels and the caption.GalvanometerElectric motor Loudspeaker

Generator Step-Up Transformer

Step-DownTransformer

Electromagnetism FoldableGalvanometer: Fig 5 on p. 630 (Fig 10 p.

638)Electric motor: Fig 6 on p. 631 (Fig 11 p.

639)Loudspeaker: Speaker pic on p. 635

(none)Generator: Fig 3 on p. 634 (Fig 14 p. 643)Step-Up Transformer: Fig 7A on p. 638

(Fig 16B p. 645)Step-Down Transformer: Fig 7B on p.

638 (Fig 16A p. 645)