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aap216 aap216
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10 years ago
I know that the magnetic force in an electric current wire is always perpendicular to the wire. Hence the compass needle aligns with the magnetic force and also becomes perpendicular. I really need to know HOW and WHY the magnetic force is perpendicular to the current. Is the right hand rule also involved?

PLs explain this as simply as you can because I am really confused about this.
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wrote...
10 years ago
The right hand rule (and the left hand rule) only shows the direction of the field related to the wire's current.
The magnetic field cannot be in the direction of the current, that's just a basic physical fact!. If a current flows, a magnetic field is formed perpendicularly to it.
It happens with radio waves and light waves, also. Voltage and magnetic fields are perpendicular to each other.
wrote...
10 years ago
the reason it is perpendicular is purely mathematical and experimental fact. if it were not perpendicular some of maxwell's equations would not hold (primarily ampere-maxwell law and faradays law) it does have to do with the right hand rule because of the curl operator. it just so happens these two equations of maxwell are the most important in the whole bunch (differential form).
wrote...
10 years ago
I know that the magnetic force in an electric current wire is always perpendicular to the wire. Hence the compass needle aligns with the magnetic force and also becomes perpendicular. I really need to know HOW and WHY the magnetic force is perpendicular to the current. Is the right hand rule also involved?

Yes the right hand rule is the way you determine the direction of the magnetic field.

If an electric current was running clockwise, a magnetic field would be produced with its N pole pointing into the clock. This is difficult to show with your right hand. Hold your right hand with your thumb pointing at you and your fingers curled. They are curled counter clockwise. The direction that your thumb is pointing is the North pole of the magnetic field produced by the current.

Draw a circle with arrows pointing clockwise. For your fingers to be curled clockwise, your thumb has to be pointing into the paper. N is into the paper

I know that the magnetic force in an electric current wire is always perpendicular to the wire. First the HOW answer!!
ELECTRICITY AND MAGNETISM ARE 2 SIDES OF THE SAME COIN!!!

ELECTRICITY AND MAGNETISM ARE SOUL MATES RUNNING PERPENDICULAR TO EACH OTHER, AND IN-SYNC.

WHEN ONE MOVES CLOCKWISE, THE OTHER MOVES ALONG A LINE PERPENDICULAR TO THE PLANE OF THE CIRCLE AND THRU THE CENTER OF THE CIRCLE!!

ONE DOES NOT EXIST WITHOUT THE OTHER, WAITING NEARBY.AS SOON AS ONE MOVES, BAM, THE OTHER IS BORN AND MOVING!


If you have a compass, some wire WITH its coating still on it (not bare wire), and a D-cell battery, you can do this simple lab and understand magnetism better.

To make a magnet, you wrap a coil of wire around an iron screw driver. The reason I choose an Iron screw driver is because iron has, what we call in chemistry, free electrons. The valence electrons are not trapped in a bond between 2 Fe atoms. MORE ON THIS TOPIC LATER!.  OK, back to the wire wrapping.  Before you start, bare about 1? of wire to attach to the battery.
DO NOT WRAP THIS BARE WIRE AROUND THE METAL OF THE SCREW DRIVER, YOU NEED IT TO ATTACH TO THE BATTERY!!

Hold the screw driver with the point facing your face. Wrap the wire clockwise, starting from the far end, and wrapping toward your face. When you get to the end nearest you, do not wrap back to the other end. If you have more wire, go straight to the far end and wrap clockwise toward you again. The more wrappings, the stronger the magnet will be.
When finished bare this end of the wire.
You are almost ready. Lay the compass on the edge of a level surface, away from any metal. The best is a wood table. When I say go, you will hold the 2 bare ends on the 2 terminals of the battery, and hold the point of the screw driver close to the compass. GO!!
 The compass needle should move quickly to point the same direction as the screw driver. Rotate the compass and the compass needle should remain pointing at the screw driver.

Turn the battery around, so the electricity is flowing the opposite direction. The needle should do a 180° rotation. You can turn the screw driver 180° and see what happens. Remove the bare wires from the battery and see if the screw driver still affects the compass.

NOW BACK TO THE ELECTRONS IN IRON
In the presence of a magnetic field, these free electrons in groups of atoms called domains will align themselves so they are all orbiting the same direction. This produces a miniature magnet. In an iron rod that is not magnetized, these domains are aligned randomly. When you drag a weak magnet from the N pole of a strong magnet towards the south pole of the strong magnet, the strong magnetic field will force these domains to align parallel to the magnetic field of the strong magnet. Now the iron rod is a magnet.

Remove the wire from the screw driver so you can do the next lab.

Now let?s see how a magnet produces electricity. Wrap the wire as before around an empty toilet paper roll, instead of a screw driver or iron rod. Attach the bare ends to a galvanometer. Ask a physics teacher to help you if you can not find a galvanometer. I have used a DC multi-meter and set it to measure milli-amps.
As you move a magnet into the core of the toilet paper roll, the galvanometer needle will move. Note the direction. As you slowly pull the magnet out of the core, watch the direction the needle moves
 
In almost summary, you have observed electricity produce a magnetic field, and you have observed a magnet produce electricity.

I want to address your comment shown below:
?I know that the magnetic force in an electric current wire is always perpendicular to the wire.?
 
The magnetic field moves in a circle. The plane of the circle is perpendicular to the line determined by the flow of the electrons (electric current)

I have described HOW to use a magnet to produce electricity, and HOW to use a battery to make a magnet from a screw driver.

NOW FOR THE YOUR STATEMENT BELOW
I really need to know HOW and W
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