how many poles do all magnets have?
what hapens if a magnet breaks in half?
each piece becomes a magnet with 2 poles
who discovered that a current-carrying wire caused a compass needle to move?
the domains are aligned in a magnet.
true or false
what is the right hand rule used to demonstrate?
the direction of current and magnetic field
what kind of magnets are the strongest ones?
how can alternating current be generated?
moving a magnet in and out of a coil wire
what is the frequency of alternating current in the U.S.?
can magnetic poles be seperated?
when is the magnetic force on a charged particle or a current-carrying wire the greatest?
when it's perpendicular
what has a magnetic field in the shape of circles?
current carrying wire
where is the magnetic field on a magnet the strongest?
if an iron bar is inserted into the center of a solenoid, what happens to the domains in the iron?
whose law says that the magnetic field of an induced current is opposed by the magentic field that produced it ?
what device converts mechanical energy to electrical energy?
what device converts electrical energy to mechanical energy?
what are the threee ferromagnetic elements?
iron , cobalt , and nickel
what is the process of inducing an electric current by a changing magentic field?
what is a device that changes voltage called?
who are the two men that discovered electromagnetic induction was possible?
Faraday & Henry
What do scientists think causes the earth's magnetism?
moving currents in the core of the earth
what is produced when charged particles from the sun get caught in the earth's magnetic field?
whose law says that induced voltage is proportional to the number of loops of wire and the rate the magnetic field changes?
what are methods used to generate electricity?
falling water , sunlight , burning fossil, and nuclear reactions
the area around a magnet where its force is felt is called a ?
what causes magnetism?
movement of an electron or charges
what kind of meters can a galvanometer be made in to?
volmeters and ammeters
what kind of transformer lowers voltage?
what kind of transformer raises voltage?
what kind of current is sold the most today?
which pole of a magnet points toward the geographic north pole?
in what direction are the magnetic field lines drawn around a bar magnet?
north to south
how can the magnetic field be straighthened around a current carrying wire?
more coils of wire , more current , or wrap it around a nail
what is one way an iron nail can be made into a magnet?
attach it to a magnet
what are two advantages of electromagnets?
you can turn them on and off & more powerful
what happens to the poles on an electromagnet if the current changes direction?