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Physics 2 Unit I
Electrostatics part 1
Question | Answer |
---|---|
what is electrostatics? | the science that deals with stationary or resting electric charges |
what is electrification? | an imbalance of charges due to when an object becomes electricity charged by it gaining or loosing e- |
what is the difference between ionization and electrification? | ionization deals with an ion level of an individual atom; electrification deals with the entire object |
what are the 3 methods of electrification? | friction, contact, induction |
what is the process of contact? | when one object is neutral is the other has a charge. Excess e- or protons will go to the neutral object so that both objects become balanced with whatever charge the object with excess had. |
How does combing your hair and then touching a piece of paper cause static electricity? | The comb receives excess e- that were transferred to the comb from the hair. Once the comb touchesc the paper, the e- on the paper are repelled from the - charged comb and then the paper becomes more + charged. Then a "shock" occurs when the two attract. |
name the one object that is always available to accept electric charges from an electrified object. | Earth |
Out of the 3 methods of electrification, which one is involved when lightning is formed? | induction; when the cloud and wind movement removes e- from one cloud and deposits them on another (clouds have opposite charges)qgR |
what is the smallest unit of electrical charge? | an electron |
what does it mean when an object is said to be electrified? | if it has too many or too few electrons |
what is the difference between contact and induction in the methods of electrostatics? | contact: begins with a neutral & one charged object the result=both objects are electrified with same charge induction: one charged object and results in both objects electrified with opposite charges. induction uses the electrical field also. |
True or False: Induction includes contact with the two objects involved. | False. |
True or False: electrostatic force between 2 charged objects is inversely proportional to the product of their magnitudes & directly proportional to the square of the distance between them. | False. force increases; magnitude increases DIRECT. if 2 like charges decrease the distance between them (closer together) then their pull (repel) is stronger (increase) |
Why is it that if you have like charges closer together their pull (repelling) will be stronger to bring them together? | Because when you bring like charges closer together; they are repelling due to the overlap of their electrical fields=greater force trying to push them together. |
True or False: static charges only reside on the external surface of an object. | True |
On a curved surface where is the concentration of charges the greatest? | on the greatest curve of the object |
Which charges are only able to move thru a solid conductor? | negative charges |
what is electrodynamics? | the science of electrical charges in motion |
what causes an e- to move? | a surplus of e- in one place and a deficit in another. when the surplus e- come near the object with the deficit the e- in the deficit move away creating that object to now have a + charge. |
what are the four materials used in electrical circuits? | 1. conductors 2. insulators 3. semi-conductors 4. superconductors |
what are examples of good conductors? | copper, silver, water |
what is an insulator? | materials that inhibit the e- to flow; used to confine the flow of e-. opposite of conductors |
what is a conductor? | any substance through which electrons flow easily |
what is the difference between a superconductor and a semi-conductor? | superconductors allow e- to flow through a circuit w/o resistance. Conductors have resistance. |
what is a semi-conductor? | special materials which can be either insulators or conductors by nature. In certain circumstances they can perform the opposite function. |
what are examples of good insulators? | glass, clay, earthlike materials |
what are examples of semi-conductors? | silicon, germanium |
what are examples of superconductors? | niobium, titanium, magnets in MRI; for material to behave as a superconductor it must be made very cold (requires more E) |
what is it called when the conductor is enclosed in a spare pathway and the flow is controlled? | electric circuit |
Describe the nature of an electric current when e- flow thru the conductor. | the outershell e- are loosely bounded, they can be made to move under certain circumstance. individual e- move fairly slow; an electrical current moves very fast (almost light speed). |