physics ch.13, 32, 33

electric dipole

An electric dipole is a separation of positive and negative charges

electric fields

a force field surrounding an electric charge

charged conductors

absence of an electric field comes about b/c of how free electrons within the conductor stop moving when the electric field is zero. charges arrange themselves to ensure a zero field within the material. if the conductor is not spherical, then the charge distribution will not be uniform .

an ion is

an atom that has more electrons than protons or an atom that has fewer electrons than protons

according to Coulomb's Law, electrostatic force is directly proportional to

charge

the SI unit of charge is

coulomb (C)

compare the strengths of the gravitational force and the electrical force

electrical force is much stronger than gravitational force

how do electrical and gravitational forces compare?

electrical forces are much stronger than gravitational forces, electrical forces can be attractive or repulsive, whereas gravity is only an attractive force, electrical forces can be easily be seen acting between small objects, whereas gravity is most noticeable between very massive objects

electric potential

electrical potential energy per charge

in an atom the number of ________ equals the number of ________

electrons, protons

true or false; In a Van de Graaff generator, as electrons leak off the belt and onto the conducting sphere, the electric field inside the sphere steadily increases in magnitude.

false

true or false; The direction of an electric field at any point, by convention, is the direction of the electrical force on a small negative test charge, placed at the point

false

true or false; the electrical force between two protons is very small compared to the gravitational force

false

true or false; the proton has the same amount of mass as the electron, but has a smaller amount of charge than the electron

false

true or false; the proton is much larger than the electron in mass, and has a larger amount of charge than the electron

false

true or false; the proton is much smaller than the electron in mass, but has a larger amount of charge than the electron

false

in a field lines representation of an electric field, the field is weaker where the lines are ________

farther apart

what are 3 ways an object can become electrically charged?

friction, contact, and induction

the ______ is a practically infinite reservoir for electric charge

ground

gravitational force between two massive spheres

is always a force of attraction

a black hole

is the result of a massive star collapsing

an electric field has both _____ and _____

magnitude and direction

a quantity that does not change with its location is

mass

semiconductor

material that can be made to behave sometimes as insulators and sometimes as conductors ex: germanium, silicon

electric insulator

material that is a poor conductor of electricity ex: glass, rubber

electric conductor

material through which electric charge can flow ex: copper, aluminum

describe what causes lightning to occur during thunderstorms

negative charged bottoms of clouds induce and charge on the surface of the Earth below

electrons have a _______ charge

negative of -1

electrostatic force is measured in

newtons (N)

neutrons have a _______ charge

no charge or 0

electric force

one of the most powerful, fundamental forces in the universe

consider the gravitational force between Earth and a meteor in space if the meteor moves so its distance from the Earth's center doubles the gravitational force on the meteor will be

one quarter as much

describe an electrically polarized atom or molecule

one side of the atom or molecule is slightly more positive or negative than the opposite side

protons have a _______ charge

positive or +1

like charges ______ each other, and opposite charges_______ each other

repel; attract

universal law of gravitation

states that any two bodies in the universe attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them

coulombs law

the force of attraction or repulsion acting along a straight line between two electric charges is directly proportional to the product of the charges and inversely to the square of the distance between them

charge

the fundamental electrical property to which the mutual attractions or repulsions between electrons or protons is attributed

weight

the gravitational force that attracts an object to Earth

conservation of charge

the idea that charge is never created nor destroyed, but is simply transferred from one object to another

true or false; In a vector representation of an electric field, the magnitude of an electric field is indicated by the length of the vector arrows.

true

true or false; the mass of a proton is 2000 times greater than the mass of an electron

true

true or false; the proton is much larger than the electron in mass, but has the same amount of charge as the electron

true

SI unit for electric potential is

volt