Chapter 3: Electromagnetism

electromagnetism

the force that causes the interaction between electrically charged particles; the areas in which this happens are called electromagnetic fields

electromagnetism

fundamental interaction between magnetism and electricity

battery

is a device that produces electricity from a chemical reaction

1748

what year did Benjamin Franklin first coined the term battery to describe an array of charged glass plates

Benjamin Franklin

1748- (blank) first coined the term battery to describe an aray of charged glass plates

1780-1786

years when Luigi Galvani demonstrated what we now understand to be the electrical basis of nerve impulses and provided the cornerstone of reasearch for later inventors, like Volta, to create batteries.

Luigi Galvani

an italian anatomist that made an accidental discovery of the battery. He observed that a dissected frog leg twitched when touched by two different metals

1800

year of Alessandro Volta

Alessandro Volta

he discovered the first practical method of generating electricity.

zinc, copper

Constructed of alternating discs of (blank) and (blank) with pieces of cardboard soaked in brine between the metals, it produced electrical current.

voltaic pile

(name of the experiment) was the first "wet cell batterry” that produced a reliable, steady current of electricity

voltaic pile

a precursor of the modern battery

dogwood sandwich

copper-zinc plates are arranged like a (blank) to form what was called a voltaic pile

electromotive force

comes from any device that converts some form of energy directly into electrical energy

electric potential

electromotive force is not a force, it’s an (blank)

J/C,, V

electromotive force has a unit of

electromotive force

it is the maximum potential difference between two electrodes of volataic cell

electromotance

electromotive force is also called as

hans oersted

he discovered that electric currents create magnetic fields, an important aspect of electromagnetism

hans oersted

discovered the first link between electricity and magnetism

any charged particle in motion induces a magnetic field, any charged particle at rest induces no magnetic field, the direction of the magnetic field lines can be describe by doing the experiment: the right-hand rule

hans oersted conclusions (3)

right-hand rule

determines the directions of the magnetic force, conventional current, and the magnetic field

conventional current

I stands for (right-hand rule)

magnetic force

F stands for (right-hand rule)

magnetic field

B stands for (right-hand rule)

solenoid

a coil of wire

solenoid

a long straight coil of wire that can be used to generate a nearly uniform magnetic fieldelectro

electromagnets

current-carrying wire wrapped around an iron core

electromagnets

unlike permanent magnet, the strength of an electromagnet can easily be changed the amound of electric current that flows thru it. reverse it.

current

electromagnet: the strength of the magnetic field generated is proportional to the amount of (blank)

electromagnetic induction

the production of an electric current across a conductor moving through a magentic field

electromagnetic induction

underline the operation of generators, transformers, induction motors, electric motors, synchronous motors, and solenoids

michael faraday

is generally credited with the discovery of induction in 1831

michael faraday

he concluded that the magnetic field can be used to generate electric current

an electric current can be induced in a circuit by changing magnetic field

faraday’s law

the strength of the magnetic field, the velocity of the magnetic field as it moves past the conductor, the angle of the conductor to the magnetic field, the number of turns in the conductor

factors that govern the induction in faraday’s law

Heinrich Lenz

discovered the directional relationships between induced magnetic fields, voltage, and current when a conductor is passed within the lines of the force of a magentic field

lenz’s law

the second law of electromagnetic induction

lenz’s law

states that the direction of the induced current opposes the action that induces it

electric generator, electric motor, induction motor

what are the two electromechanical devices

electric generator

practical application of the Faraday’s law

electrical generator

a device that converts mechanical energy into electrical energy

electric motor

practical application of oersted

electric motor

transforms electrical energy to mechanical energy

induction motor

type of motor used in x-ray machines

rotor

the part of the motor located inside the glass envelope of the x-ray tube

stator

they are fixed electromagnetss outside the glass envelope of the x-ray tube

commutator ring

acts like a switch changing the polarity of the contact of the loop of the wire

self-induction, mutual induction

two types of induction

self-induction

induction of the opposing EMF or opposing voltage ni a single coilnby its own changing magnetic field.

DC

mutual induction

generation of an alternating current in a primary coil

secondary coil

(mutual induction) coil with the induced current

primary coil

coil thru whichthe varrying current is passed