Term
| What is the cause of magnetism? |
|
Definition
|
|
Term
| What are the three degress of magnetism? |
|
Definition
| ferromagnetic--strongly attracted; paramagnetic--slightly attracted; diamagnetic--slightly repelled |
|
|
Term
| Why is iron ferromagnetic? |
|
Definition
| unpaired electron spins line up parallel with each other forming domains |
|
|
Term
|
Definition
| temperature above which a ferromagnetic material stops being ferrogmagnetic |
|
|
Term
| What is a magnetic field? How are the field lines drawn? |
|
Definition
| the area around a magnet or moving charge in which a force is felt; field lines drawn from north to south |
|
|
Term
| What happens to the strength of the field as the number of field lines increases? |
|
Definition
| the field strength increases |
|
|
Term
|
Definition
| microsocopic area within a ferromagnetic material in which the atoms are magnetically alligned |
|
|
Term
|
Definition
| high school teacher that discovered the link between electricity and magnetism |
|
|
Term
|
Definition
| he came up with the hand rules |
|
|
Term
| What did Michael Faraday and Joseph Henry do? |
|
Definition
| they discovered electromagnetic induction |
|
|
Term
| What is Ampere's Rule for the Straight conductor (first hand rule)? |
|
Definition
| current-right hand; electrons-left hand; thumb always points away from the current |
|
|
Term
| How do you make an electromagnet? What are the three factors that affect the strength of an electromagnet? |
|
Definition
| you need wire, a ferromagnetic material to wrap it on, and a battery; 3 factors--how many wraps, type of core, and current |
|
|
Term
| How do you use Ampere's Rule for a soelnoid to determine the N-pole of an electromagnet? |
|
Definition
| thumb points north; follow the wire with your fingers |
|
|
Term
| What is the motor effect? |
|
Definition
| a current-carrying wire placed in a magnetic field will move |
|
|
Term
| How do you calculate the force exerted on a current carrying wire in a magnetic field? |
|
Definition
|
|
Term
| HOw do you calculaethe foce exerted on a harge moving in a magnetic field? |
|
Definition
|
|
Term
| What are the three parts of the motor? |
|
Definition
| armature, magnets, connection |
|
|
Term
| What type of energy conversion occurs in an electric motor? |
|
Definition
| converts electricity to motion |
|
|
Term
| Who discovered electromagnetic induction? |
|
Definition
|
|
Term
| What is electromagnetic induction?What three factors affect how much current is produced in electromagnetic induction? |
|
Definition
| production of voltage across a conductor through a magnetic field; speed, strength, and number of turns |
|
|
Term
| HOw do yo9u fetermine the EMF produced by a wire being moved in a magnetic field? |
|
Definition
|
|
Term
| What is the main application of electromagnetic induction? |
|
Definition
|
|
Term
| What is the difference in an ACgenerator and a DC generator? |
|
Definition
| AC generator has 2 slip rings; DC generator uses a split ring commutator |
|
|
Term
| HOw are motors and generators similiar and how are they different? |
|
Definition
| they have the same parts; motor converst electrical to mechanical; generator converts mechanical to electrical |
|
|
Term
|
Definition
| the induced current is always in the direction to oppose the motion that caused it |
|
|
Term
| What is back EMf and how is it produced? |
|
Definition
| caused by the generator action of a motor |
|
|
Term
|
Definition
| a changing current in a coil of wire is going to produce a changing magnetic field |
|
|
Term
|
Definition
| the inductance of EMF in a wire carrying a changing current |
|
|
Term
| What is mutual inductance? |
|
Definition
| effect in which a changing current through a trasnformer's primary coil creates a changing magnetic field, which is carried through the core to the transformers secondary coil, where the changing field induces a varying EMF |
|
|
Term
| How does a transformer work? |
|
Definition
| application of mutual inductance |
|
|
Term
| What is the differnce in a step up transformer and a step down transformer? |
|
Definition
| step up-steps up the voltage; step-down--steps down the voltage |
|
|
Term
| Where does the Earth's magnetic field come from? |
|
Definition
| comes from inside the Earth; convection currents of molten material generates the field |
|
|
Term
| Why is the EArth's magnetic field important to life? |
|
Definition
| protects us from ionized radiation |
|
|
Term
| What is the aurora borealis? |
|
Definition
| where teh particles from the sun hit our atmosphere |
|
|
Term
| What are some uses of magnetism in today's world? |
|
Definition
| motors, generators, refrigerator magnets |
|
|
Term
| What hand do you use with current? electrons? |
|
Definition
| current, right hand. electrons, left hand |
|
|
Term
|
Definition
| magnetic field strength, how many lines per area (tesla) |
|
|
Term
|
Definition
| the way of counting the field lines (webers) |
|
|
Term
| Magnets are made of what kind of material? |
|
Definition
|
|
