67 terms

physics chapter 16

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dry days because there is not enough moisture to "connect" the charges
when does one notice static charges most?
convection
rub hair with balloon, the balloon becomes negatively charged and your hair becomes positively charged
between
negative electrons move ________ material rather than protons
fixed
protons are too __________ inside the nucleus
ions
atoms that have gain or lost electron and therefore have a charge
transfered
charges can only be....
a charged object's charge is always a multiple of a fundamental charge (quantized)
what did Millikan discover?
Millikan's Oil Drop experiment
-Observed the motion of oil drops between two parallel charged plates
-Gravity initially pulled the droplets down - when the top plate was given a positive charge, the droplets with negative charges were attracted to the top plate
1 electron
fundamental charges is the charge of...
coulomb (c)
what is the SI unit for charge?
q
what is the variable for charge?
conductors
materials that allow charges to flow easily from them
insulators
materials that do not allow charge to flow through them
semiconductors
normally insulators, but adding specific atoms as impurities can turn them into conductors (silicon, germanium - used a lot in electronics)
superconductors
zero electrical resistance when below a certain temperature - can conduct electricity without heating up
contact
rubbing two materials together - one object rubs the electrons off the other, making it positively charged
true
t/f both insulators and conductors can be charged by contact
grounded
conductor connected to the Earth by a conducting wire or copper pipe
induction
A neutral conductor is brought near another charged object, then the conductor is grounded - no touching necessary
conductors
only _____ can become charged by induction
polarization
A surface charge can be induced on insulators by....
polarization
shifting of charge within an atom
zero
polarized object have a net charge of...
does not
polarization ______ ______ require contact, just proximity
coulomb's law
The closer two charges are, the greater the force of attraction or repulsion between them
F = (kq1q2)/r2
what is the equation for coulomb's law?
k
what is coulombs constant?
point charges or particles and spherical distribution of charges
Coulomb's Law only applies to....
field force
force between two objects that are not in contact with each other
attractive, repulsive
electric forces can either be ________ or _______
electric field
area around a charge where the charge can be "felt" by another object
test charge
used to detect the presence of an electric field
E = Felectric/qo
what is the equation for electric field?
N/C
what is the unit for electric field?
stronger charge
Lines closer together=
Electric Dipole
two equal in strength, same charges - field lines are identical and turn away from each other
zero
Electric field is ____ inside the conductor
outside
Charges reside only on the ______ of the material.
perpendicular
Electric field is _____ to the material's surface
irregularly
Charges accumulate at points for _______ shaped objects
repel
Like Charges do this
NO
Does the magnitude of a test charge affect the electric field of the charge?
positive to negative
Electric field lines point in this direction
direction/charge
Coulomb's law does not tell the ____ of the electric field force.
bigger/stronger
Close electric filed lines mean _________ charge.
conduction
Charge by touching
induction
Charge transfer without touching
equal and opposite
Two charges exert _____ and _____ forces on each other.
neutral
The electric field strength inside a hollow, charged metal ball
Millikan
He measured the charge on an electron
q
Symbol for charge
positive
Sign of a "test charge"
positive
Charge value for a proton
N/C
Unit for electric field
coulomb
Unit for charge
lightning
Natural example for static discharge
electron field
Area around a charge where it can be "felt"
coulombs law
Name for the equation F = k(q1q2)/r2
static electricity
Charge that doesn't move
attract
Opposite charges will do this
negative
When rubbing a balloon on your head, the balloon becomes ____ charged.
K
Value of Coulomb's constant
edge
Charges accumulate on the __________ of a sphere
electroscope
Tool used to determine the presence of a charge.
less charge
bigger circumference=
static electricity
accumulation of electric charges on an object
electric field
exerts a force on anything that has an electric charge