Physics Ch. 17-18

PEelectric=______________ at infinity, which serves as the reference point

0

E is measured in ______________

N/C

A Van de Graff Generator is a machine designed to generate a large build up of electric charge a. true b. false

a

Doubling the distance from a point charge would cause the electric field to become a. one-fourth as great b. one-half as great c. twice as great d. four times as great

a

Electric potential a. measures energy per unit charge b. is the same as electrical potential energy c. is measured in joules d. at a point depends on the charge at that point

a

Electric potential energy depends on the size of the charge placed at a particular location while electric potential does not a. true b. false

a

How will the electric force between two charges change when the distance between them decreases to one-fourth the original distance? a. it will increase to 16 times the original value b. it will increase to 4 times the original value c. it will decrease to one-fourth the original value d. it will decrease to one-sixteenth the original value

a

Measuring electrical potential energy requires a reference point. The most commonly used reference point is a. the initial position of a charge b. the final position of a charge c. the midpoint between the initial and final positions of a charge d. infinity

a

The atoms of objects that are positively charged have a. lost electrons b. gained electrons c. lost protons d. gained protons

a

The transfer of charge from one object to another through direct physical contact is called a. conduction b. induction c. polarization d. quantization

a

Which of the following is not a property of electric field lines? a. the field is perpendicular to the field lines at each point b. the number of lines per unit area is related to the strength of the field c. they point away from positive charge and toward negative d. field lines never cross

a

A capacitor is an energy storage device. The energy stored by the capacitor is the a. charge on the capacitor's plates b. energy required to move charge onto the capacitor's plates c. capacitance of the capacitor d. potential energy difference between the plates of the capacitor

b

A conductor can be charged by _____________, but an insulator cannot a. grounding b. induction c. polarization d. contact

b

A material that does not transfer charge easily is called a a. conductor b. insulator c. semiconductor d. superconductor

b

Given that a conductor of non-uniform radius is in electrostatic equilibrium, which of the following statements is correct? a. charge tends to be greatest where the radius of the conductor is largest b. charge tends to be greatest where the radius of the conductor is smallest c. charge accumulates on the inside surface of the conductor d. charge remains the same everywhere along the conductor

b

The amount of electrical potential energy that can be stored in a capacitor is directly related to the capacitance of the capacitor. Which of the following will not increase the capacitance of a capacitor? a. increasing the area of the plates b. increasing the spacing between the plates c. reducing the spacing between the plates d. placing an insulating material between the plates

b

The electrical potential energy of a charge in a uniform electric field a. does not change if it moves perpendicular to the field b. does not change if it moves parallel to the field c. decreases with increasing strength of the electric field in which the charge is located d. decreases as the magnitude of the charge increases

b

The purpose of Millikan's Experiment was to determine the mass of the electron a. true b. false

b

The type of charging in which a positive rod is used to lure electrons onto an object through grounding is called a. conduction b. induction c. polarization d. quantization

b

Which of the following does not correctly describe electric charge? a. objects are electrically charged through rubbing b. like charges attract and opposites repel c. the charge on any object is always a multiple of the elementary charge d. electric charge is conserved

b

Which of the following is not a property of a conductor in electrostatic equilibrium? a. the electric field is zero everywhere inside the conductor b. any excess charge resides inside the conductor c. the electric field just outside the conductor is perpendicular to its surface d. on non-spherical conductors, charge tends to accumulate at sharp corners

b

______________ do work by moving charges through a potential difference, giving them the energy needed to travel through an electric circuit

batteries

A conductor that is in electrostatic equilibrium has an electric field inside the conductor that a. is greatest at the center of the conductor b. is perpendicular to the conductor's surface c. is zero d. depends on the radius of the conductor

c

A force of attraction always exists between two charged objects when a. the charges on both objects have different magnitudes b. the charges on both objects have equal magnitudes c. the charges on the objects have opposite signs d. both objects have charges with the same sign

c

A material that has few freely moving charge carriers is most likely to be classified as a(n) a. metal b. semiconductor c. insulator d. conductor

c

Electrical potential energy is not a. the result of charge interacting with an electric field b. the result of charges interacting with each other c. a property of an isolated single charge d. a form of mechanical energy

c

The electrical potential energy of a negative charge _____________ when a force moves the charge in the same direction as a uniform electric field to a new position in the field a. temporarily increases, then returns to its previous value b. decreases c. increases d. does not change

c

The fundamental unit of electric charge is equal to the charge on a a. hydrogen atom b. oil drop c. single electron d. single neutron

c

The process of charging by contact works a. only for insulators b. only for conductors c. when unlike materials rub against each other d. when a charged object comes in contact with the ground

c

The type of charging in which a neutral object has its positive and negative centers of charge realigned is called a. conduction b. induction c. polarization d. quantization

c

When the potential difference across a capacitor is reduced, the a. capacitance decreases b. capacitance increases c. charge decreases d. charge increases

c

Which of the following does not correctly describe a dielectric material? a. a dielectric is an insulating material b. air, rubber, and glass are common dielectric materials c. adding a dielectric to a capacitor decreases its capacitance d. applying high voltages across a capacitor can destroy a dielectric

c

Which of the following does not correctly describe a fully charged capacitor? a. one plate is positive and the other is negative b. the net charges on the two plates are equal in magnitude c. the net charges on the two plates have the same sign d. the voltage across the plates is the same as that of the battery

c

Which of the following is not a characteristic or property of an electric field? a. a region in space b. surrounds a charged object c. exerts electric force on all objects entering it d. not detectable by an uncharged object

c

Which of the following statements is incorrect? a. gravitational force and electric force are both field forces b. gravitational force is only attractive c. electric force is weaker than gravitational force is d. gravitational force and electric force both decrease as the separation between the objects involved increases

c

Which particles are most easily transferred from one object to another? a. protons b. neutrons c. electrons d. ions

c

______________: a measure of the amount of electric charge stored (or separated) for a given potential difference

capacitance

______________: a device that stores electric charge and energy in a way that can be reclaimed later when needed for a specific application

capacitor

Electric ______________-a property of a particle by which it may repel or attract other particles

charge

Millikan's Experiment examined the motion of tiny oil droplets between a pair of parallel metal plates as a means of determining the ______________ of an electron

charge

uniform electric field formula: q

charge

______________: works with both conductors and insulators and involves actual charge transfer from one object to another through physical contact

conduction

In a good ______________, charges are free to move about within the material

conductor

______________ transfer charge easily

conductors

When a large number of charges accumulate on the surface of a conductor, the strong repulsive forces between them sometimes cause one or more of them to jump to the surrounding air, and a bluish glow called the ______________ is produced

corona

Electric ______________-a flow of electric charge

current

A negatively charged sheet of plastic will stick to a glass window by a. taking electrons from the glass b. taking protons from the glass c. giving electrons to the glass d. polarizing the glass

d

When a capacitor is connected to a source of potential difference, charge accumulates on the two plates of the capacitor. The accumulation of charge ceases when the a. charge on the two plates is equal b. charge on one plate is greater than the charge on the other plate c. net charge on the capacitor becomes zero d. potential difference between the plates is equal to the external source of potential difference

d

Which of the following statements about the drawing of field lines between charges is correct? a. field lines always form closed loops b. field lines always connect from one charge to another c. field lines can start on a charge of either polarity d. field lines do not exist

d

Which of the following statements is incorrect? a. potential difference is directly proportional to change in electrical potential energy b. potential difference measures the change in the electrical potential energy of a charge c. the SI unit of potential difference is the volt d. potential difference is the ratio of the magnitude of a charge to its change in potential energy

d

______________: an insulating material used to fill the space between the plates of a capacitor (often air, rubber, waxed paper, or polystyrene)

dielectric

With a pair of point charges, the electric potential energy associated with a pair of point charges varies with the ______________ between them

distance

uniform electric field formula: d

distance

______________: the region in space surrounding a charged object in which a stationary charge experiences an electrostatic force

electric field

______________: lines that represent and help us to visualize both the magnitude and direction of the electric field surrounding one or more charges

electric field lines

______________: the electric potential energy per unit charge at any location in an electric field

electric potential

______________-the study of electric charges at rest

electrostatics

Electrostatic ______________: the condition in which there is no net motion of charge within a conductor

equilibrium

capacitance is measured in

farads

______________: works only with conductors and involves no physical contact between objects

induction

______________ do not transfer charge easily

insulators

In a uniform electric field, the electric potential energy associated with a charge as it is moved ______________ to a uniform field is given by PEelectric=-qEd

parallel

Displacement ______________ to the field does not change the electric potential energy of a charge

perpendicular

______________: similar to induction but works only with insulators and involves no physical contact between objects

polarization

field lines always point away from ______________ charge and towards ______________ charge

positive, negative

______________: the change in electric potential energy per unit charge between two points in an electric field

potential difference

The strength of the electric field at any particular location can be found by placing a small positive test charge, ______________, at that location, measuring the force, ______________, acting on it, and then calculating the force per unit charge being exerted

q, F

Electric charge is "______________"-the charge on any object is always a multiple of a single proton or electron

quantized

Objects are electrically charged through ______________

rubbing

______________ has properties somewhere between that of a conductor and an insulator

semiconductors

Since electric potential energy depends on the ______________ of the charge, its value is not unique to any particular point in an electric field

size

uniform electric field formula: E

strength of electric field

______________ become perfect conductors when at or below a certain temperature

superconductors

Principle of ______________: if more than two charges are present, the net electrostatic force on any one of them is given by the vector sum of the forces exerted on that charge by all of the other charges that are present

superposition

electric potential is measured in ______________

volts

When a charge is moved with or against an electric field, ______________ is done, and the corresponding potential energy changes

work

______________ is done by an external force whenever a charge is moved through a potential difference

work