Chapter 19 - Electric Forces and Fields Flashcards
what is an easy way to give objects a net charge
rubbing
how do you get charge differences by rubbing
dislodged electrons can cling to one object, leaving the 2 objects with equal and opposite net charges
what does it mean for metal to be a conductor
electrons are relatively free to move about
what does it mean for an object to be an insulator
electrons are not free to move about
what is induced polarization
induced charge separation
what kind of object can get induced polarization
conductors AND insulators
what does it mean that insulators can do induced polarization
there can be attraction between a neutral and any charged object!!! (tiny dipole on molecular scale)
what is coulombs law
magnitude of force between two point charges
when should you put a negative in front of coulombs law
if the charges are attracted
when should you put a positive in front of coulombs law
if the charges are repulsed
how do you find the Fnet acting on charge q
you do a vector sum of individual forces
why can we say that each object is just a point
because the size of object «_space;relevant distances
is electric field scalar or vector + why
vector because it has a magnitude and direction that may vary with the location in the field
what does the magnitude of E represent
force per unit charge exerted on q at that location
how do you determine the direction of E
its the direction that a +ve charge would experience at that location
how do you show that an electric field is strong with lines
when they are closer together, it means that they are stronger
what is proportional to the magnitude of the charge
the total # of electric field lines
how do you find the net E field at some location with multiple charges present
use vector addition
where do the lines begin and end when drawing electric field lines
start on + and end on -
what is another way to call electric field lines
lines of force
what is another way to call lines of force
electric field lines
do lines of force ever cross
no
do electric field lines ever cross
no
what is the direction of force of a + charge in an electric field
in the same direction as the electric field lines
what is the direction of force of a - charge in an electric field
in the same opposite as the electric field lines
what is a uniform electric field
when the electric field in a region is uniform if the magnitude and direction are constant everywhere within the region (parallel and evenly spaced lines)
if a conductor carries a net charge, where will excess charges go
they will reside on the surface
if a conductor carries a net charge, where will E field lines be
emerge perpendicular to the surface
if a conductor carries a net charge, what is the E inside the conductor
0 unless there is a charged object inside the conductor
if a conductor carries a net charge, where do charges tend to bunch up + what does this lead to
near points and sharp edges, leading to a strong electric field
