Ch. 21

Question 1

What is the difference between electric potential and Electric potential energy

Answer 1

Electric potential is created by a source charge whereas electric potential energy describes the interactions between a charge and the potential

Question 2

is there always electric potential even if there is no charge to experience it?

Answer 2

yes, there is always an electric potential

Question 3

what creates electric potential energy

Answer 3

when a charge is moved to a region with greater electric potential, it requires more work to move the charge, this work is transformed into potential energy that is stored in the charge

Question 4

what happens when a charge is moved from a region of high to low potential?

Answer 4

it’s speed increases as its energy is transformed into kinetic energy

Question 5

How are potential differences created?

Answer 5

they are created by a separation of charge

Question 6

what are two sources of potential differences

Answer 6

batteries and capacitors

Question 7

how do batteries create potential differences

Answer 7

they use chemical means to separate charge and produce a potential difference

Question 8

how do capacitors create a separation of charge

Answer 8

the opposite charges on the plates of a capacitor create a potential difference between the plates

Question 9

what are equipotential surfaces

Answer 9

at all points, the potential is the same

Question 10

how are electric fields and equipotential surfaces related

Answer 10

electric field is always perpendicular to an equipotential surface

Question 11

what happens to a charge as it moves along an equupotenital surface

Answer 11

the potential energy does not change as it is not moving along the field

Question 12

what direction does the electric field point relative to the potential

Answer 12

it points downhill, in the direction of decreasing V

Question 13

what are the 5 qualities of a conductor in electrostatic equilibrium

Answer 13

all excess charge is on the surface

the electric field on the interior is zero

the exterior electric field is perpendicular to the surface

the field strength is the largest at sharp corners

The entire conductor is at the same potential and so the surface is an equipotential

Question 14

what can capacitors do in relation to charge and energy

Answer 14

they can be used to store charge and potential energy

Question 15

how are work and potential energy connected

Answer 15

the amount of work done is equal to the amount of potential energy stored

Question 16

how is a objects potential energy related to its charge

Answer 16

if a object has a greater charge, it will require greater amounts of work to move, so it will store more potential energy

Question 17

if ∆KE is positive, what happens to the speed of the charge and how did it move relative to the potential

Answer 17

it sped up, it moved from a region of high potential to low

Question 18

if ∆KE is negative, what happens to the speed of the charge and how did it move relative to the potential

Answer 18

it slowed down, it moved from a region of low potential energy to high

Question 19

when q is negative, what happens to the kinetic energy when it moves from a region of low potential energy to high

Answer 19

it is attracted to the high potential region so its Kinetic energy increases

Question 20

what happens to the potential energy a negative charge as it gets closer to the point charge

Answer 20

its potential energy decreases and kinetic energy increases

Question 21

what do source charges create

Answer 21

they create fields and electric potentials

Question 22

if you increase the charges on two electrodes on a capacitor, what happens to the potential difference?

Answer 22

it increases, it is proportional

Question 23

what is a diaelectric and what does it do the the electric field in a parallel plate capacitor

Answer 23

it is an insulator that is polarized by the electric field in the capacitor.

This causes it to create its own electric field in the opposite direction and this creates a smaller net electric field

Question 24

what does the presence of a dielectric do to the capacitance

Answer 24

it increases the capacitance

Question 25

how is energy stored in a capacitor

Answer 25

it is stored in the volume of the electric field

Question 26

the electric potential outside a charged sphere is the same as a point charge

Question 27

what does the electric field and electric potential depend on in a capacitor

Answer 27

the charge

Question 28

what do 3 things do diaelectrics do

Answer 28

they decrease the electric field, decrease the electric potenital, increase the capacitance

Question 29

what do you need to make a capacitor

Answer 29

two conducting materials and an insulator in between them

Question 30

what unit is an electron volt

Answer 30

it is a unit of energy

Question 31

what does the electric field of a parallel plate capacitor depend on

Answer 31

the charge and area

Question 32

what does the Efield in a parallel plate capacitor depend on

Answer 32

it depends only on the charge of the plates and the area

Question 33

what quantity is the capacitance of a parallel plate independent of?

Answer 33

it is independent of the potenital difference (the voltage) across the plates

Question 34

what is the capacitance dependent on?

Answer 34

the area of the plates and the distance between them. if you decrease the distance between them, the capacitance is higher

Question 35

what is a capacitance

Answer 35

capacity of a material object or device to store electric charge.

Question 36

if there is a system with a proton and an electron, can the electric potential energy of the system be zero?

Answer 36

no it will be negative no matter how they are arranged