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Discover the intriguing relationship between electricity and magnetism, from the basics of magnetic fields to the wonders of electromagnetism and electromagnetic induction. Unravel the mysteries of magnets, electromagnets, and their practical applications in our daily lives.
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Magnetic Field Lines always move out of the __________end of a magnet! • East • North • South • West
Magnetic Field Lines always move into the __________end of a magnet! • East • North • South • West
Where are all magnets the strongest? • At the North Pole • At the South Pole • At both Poles • Directly in the center
Magnets can be made of iron, _________, or nickel. • Copper • Carbon • Cobalt • Cadmium
Two similar poles of a bar magnet will always _____________. • attract • repel
Two opposite poles of a bar magnet will always _____________. • attract • repel
Electromagnetism --the relationship b/w electricity and magnetism
Is there a relationship between electricity and magnetism? Let’s see what I discovered!!! Hans Christian Oersted
Oersted’s Law • The flow of electricity through a wire conductor produces a magnetic field around the wire.
Right Hand Rule • The direction of the current determines the direction of the magnetic field.
2 things affect the strength of a magnetic field: • Amount of current • Increase current = increase strength • Decrease current = decrease strength • # of coils of wire • More turns of wire = more strength • Less turns of wire = less strength
I was just wondering what would happen if I slammed an iron core through a current carrying coil of wire? What did you find out?
If you take an iron core and insert it into a coil of current carrying wire, you have a temporary magnet called an electromagnet!!
Strength of an Electromagnet • 2 things affect the strength of an electromagnet(same 2 things that affect the strength of a magnetic field): • Amount of Current • # of turns of wire(# of coils)
What happens to the strength of an electromagnet if the current through the wire increases from 4 A to 9 A? • Remains the same • Increases • Decreases
Uses of Electromagnets • Electric Meters: because of their ability to detect current(only work when there is one), electromagnets are used in a variety of electric meters. • Ammeter—measures current • Wired in series • Voltmeter—measures voltage • Wired in parallel • Galvonometer—”detects” current
Uses of electromagnets(cont.) • Motors • Use electromagnets to convert electrical energy into mechanical energy • An electromagnet turns inside a permanent magnet
If current moving through a wire produces a magnetic field, I wonder…… ….What would happen if we move a wire through a magnetic field
I bet it has never been tested. Let’s try it!!! I’ll try anything once!!
Haven’t we already done that? Joseph Henry Michael Faraday
Faraday and Henry discovered that moving a wire through a magnetic field, or moving a magnetic field through a coil of wire “induced” a current on the wire!! Electromagnetic Induction—process in which moving a wire through a magnetic field produces a current on the wire.
….produces a current on a wire.“Did we just “create” electricity” • Generators—use electromagnets to convert mechanical energy into electrical energy.
Other Uses of electromagnets: Transformers Are you talking about me? Not this Kind!!!!
Alternating vs. Direct Current Alternating Current Direct Current Current only goes in one direction. • Current alternates, one direction, then the other. Plug it in, Plug it in!!
Transformers • Used to increase or decrease the voltage of alternating currents.
Transformers • Consist of 2 coils of wire. • Primary Coil • Alternating current enters • Secondary Coil • Alternating current leaves • It’s the difference in the number of turns of wire on each coil that causes the voltage the change.
2 Types of Transformers • Step-up Transformer • Increase voltage • Secondary more turns than primary • Step-down Transformer • Decrease voltage • Primary more turns than secondary
A step-up transformer has 400 turns on its primary coil and 600 turns on its secondary coil. If the primary coil is supplied with 120 V of alternating current, what will be the secondary (output) voltage? ns= 600 turns np= 400 turns Vs= ? Vp= 120