Chapter 22

Question 1

what is a current

Answer 1

it is the motion of a charge through a conductor

Question 2

when we connect a charged parallel plate capacitor to a conducting wire, what happens to the net charge od the plates and why

Answer 2

the plates are discharged as the charges flow through the wire in a current

Question 3

what are charge carriers

Answer 3

charges that move in a current

Question 4

what are conduction electrons

Answer 4

they are electrons that move around in a metal and create a current

Question 5

why can an insulator not have a current

Answer 5

no, the elecrons do not flow easily

Question 6

describe the motion of electrons in a current of a metal

Answer 6

an electric field within the metal exerts a force on the electrons that causes them to accelerate.

these electrons collide into eachother, and kinetic energy is lost as thermal energy which makes the metal warmer

Question 7

what direction do electrons move in an electric field?

Answer 7

they move opposite of the electric field

Question 8

when there is a potential difference what happens to the electric field and the current in a wire

Answer 8

the potential difference causes an electric field that points from high potential to low. This drives a current that flows from high to low

Question 9

if a conductor has a current, why is it not at equilibrium

Answer 9

the charges are in motion

Question 10

what is the law of conersevation of current

Answer 10

the current is the same at all points in a current-carrying wire.

Question 11

on either side of a bulb, what is the relationship of the current going into the bulb vs out

Answer 11

it is the same and it is conserved

Question 12

what direction does current flow?

Answer 12

it flows in the direction of positive charge

Question 13

What is another way to describe current

Answer 13

it is the rate (C/s) at which charges move through a wire

Question 14

what is the unit of current

Answer 14

it is 1 ampere= 1A= 1 coulomb per second

Question 15

what is a junction? what happens to the current of a wire when a junction is present

Answer 15

a junction is where a wire spilts or merges into one. The sum of the current in is the same as the sum of the current out

Question 16

what do batteries do for.a current

Answer 16

they keep the charges in motion through energy conversions

Question 17

how does a charge escalator work in a battery

Answer 17

due to chemical reactions, the charges are moved from the low-potential negative terminal and “lifted” to the high-potential positive terminal

Question 18

what does the charge escalator do for a current

Answer 18

it sustains the current by continuously providing a renewed supply of charges at the positive terminal

Question 19

What happens in a battery when the charge reaches the positive terminal?

Answer 19

it flows downhill from high potential to low potential and the potential energy is converted to kinetic energy as the charge flows downhill back into the battery in a complete circuit

Question 20

what is emf or ε

Answer 20

the potential difference created in a battery

Question 21

what happens to the potential difference when we connect a battery in a series

Answer 21

the potential difference is the sum of the individual batteries differences

Question 22

what in a battery creates a potential difference

Answer 22

the removal of a charge from the negative to the positive terminal

Question 22

what is a consequence of a battery’s potential difference

Answer 22

the current

Question 22

what is resistance

Answer 22

it is how hard it is to push charges through a wire

Question 22

the potential difference between the two ends of a wire connected to a battery are equal to what

Answer 22

they are equal to the potential differences in the batteries terminals

Question 23

what happens to the current when you add a battery to in a series?

Answer 23

the difference in potential increases so the current increases

Question 24

what happens to the current when you use a short and thick wire on a battery

Answer 24

the current is stronger

Question 25

what happens to the current when you use a long, thin wire

Answer 25

the current is smaller

Question 26

what are the three factors that affect current

Answer 26

the dimensions of the wire, the potential difference in the batteries, the material of the wire

Question 27

what are the units of resistance

Answer 27

ohm

Question 28

what is resistivity

Answer 28

it is an inherent property of a material

Question 29

materials with a low resistivity are good at what?

Answer 29

conducting

Question 30

materials with a high resistivity are good at what

Answer 30

insulating, they are poor conductors

Question 31

whats the difference between resistivity and resistance

Answer 31

resistivity is a property of a material whereas resistance depends on the specific geometry of a wire

Question 32

why is ohm’s law not a law of nature

Answer 32

not all objects have a constant resistance

Question 33

what are objects that adhere to ohm’s law called

Answer 33

they are called ohmic

Question 34

what are objects that do not obey ohms law lcalled

Answer 34

nonohmic

Question 35

what types of objects does ohm’s law apply to

Answer 35

resistive devices like wires or lightbulb filaments

Question 36

what objects does ohm’s law not apply to

Answer 36

batteries or capacitors

Question 37

what is a voltage drop

Answer 37

it is a decrease in potential across a resistor as we go from high potential to low potential in a current

Question 38

the electric field inside of a resistor is

Answer 38

uniform

Question 39

what happens to the chemical energy of a battery as it moves through a resistor

Answer 39

it is converted into electric potential energy, kinetic energy, and then it is transformed into thermal energy in the resistor and raises it’s tempertaure

Question 40

the rate at which a battery supplies energy is equal to what

Answer 40

the rate at which a resistor dissipates energy