Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Physics 223 > Week 6 and above until thermo > Flashcards

Week 6 and above until thermo Flashcards

You may prefer our related Brainscape-certified flashcards:
Physics 101 flashcards AP® Physics flashcards
1
Q

charge carriers in metals

A

electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

drift speed

A

net motion on a field of electrons where they flow in one direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

electron current

A

The number of electrons passing through cross section of wire per second

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

electron current depends on

A

electron’s drift speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Ne formula for number of electron that pass through the cross section during the time interval t

not the ne one

A

:)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

ie vs Ne

A

ie is the amount of electron that pass through per second. Ne is amount per time interval

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

the electrons travel a distance of:
*in a wire segment
| formula

A

;

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Volume of the cylinder of charge

formula

A

A is cross section area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

total number of electron in cyclinder

A

number of electron per cubic meter times volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

number of electron per cubic meter is

A

ne

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Formula for electron current in wire

hind start with Ne formula

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

electron current

A

number of electron per second moving through the wire

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

You can increase electron current by (3)

A

making them move faster, having more of them per cubic meter and increasing size of pipe they are moving through.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why is discharging a capacitor so fast?

+how much does the electron actually move?

A

Because the wires used are already full of e-. The electrons dont need to move the full length of the wire. The e- in wire will just be pushed out as the electron in capacitor enter wire. SO if you have a capacitor plate on neg side thats -16nC that is approximately 10^11 electrions. So 10^11 electrons (excess) would leave capacitor and enter wire and in the wire 10^11 electrons occupy xmeters in the wire so the excess electrons push 10^11 electrons which moves xmeters on the end of the wire.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what would eventually happen to the sea of electron current in a conductor and why?

A

collisions between electrons and atoms of the metal transform the electron’s kinectic energy into thermal energy and the sea of electrons will quickly slow down and stop

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

conductors with electrons moving within it are not

A

at electrostatic equilibrium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

establishing E field in wire

A

caused by nonuniform distribution of surface charges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Surface charge density in the wire at +/- and midpoint of wire

A

+ at positive plate
- at negative plate
0 at the midpoint

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

E field of a ring

A

where Z is the ring distance to the center point between the 2 ring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Why do electrons move in a through a wire as a current?

A

Bc E field inside the wire created by nonuniform surface charge pushes them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

temp of wire is raised bc of

A

collision between electron and positive non-moving ions transefer KE into thermal energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

each collision of electron with the ion…..its velocity

A

resets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

repeadtedly process of electron colliding and speeding up results …. thus the magnitude of the electrons average velocity is

A

a non zero average velocity

its drift speed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Drift speed formula

A

where v0=0

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

electron current and electric field strength relationship

A

They are porportional

stronger E field causes stronger current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

collision rate formula

A

where t= mean time betwen the collisions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

current formula with Q

A

Current is the rate at which charge crosses a point on a circuit. A high current is the result of several coulombs of charge crossing over a cross section of a wire on a circuit.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

ie and I diff

A

ie is amount of electrion per seconf
I is amount of charge per sec

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

direction of current in metal is

A

opposite the direction of motionof the electrons as current is the direction in which positive charges seem to move

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

I ie and E which is in which direction in wire?

A

ie is opposite of E and I which r same direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Current formula without resistor

Hint think about relationshio with ie

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Current density (J)

A

I/A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

the rate of electron entering bulb is

A

the same as it leaves

current doesnt change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Kirchoff’s Junction law

A

sum of current in a junction equals
sum of current leaving junction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Conductivity formula

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Conductivity and current density (J) relationship

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Diff conducting metals have diff conductivity bc

A

they have diff electron density and mean time between electron collisions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

resistivity+ what does it tell?

+formula

A

inverse of conductivity,

tell us how relunctant electrons are willing to move

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

relationship between current and potential difference at ends of the conductor

A

directly porprotional

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Resistance is a specific property of the conductor because…

A

depends on the length, diamater as well as resistvity of the material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

DIff between resistivity and resitance

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Ohm’s Law

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Magnitude of the current is determined by

A

the battery (V) and the resistance of wire

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Kirchoff’s junction law vs loop law diff

A

Junction law says that total current going in equal comming out

Loop states the total change in potential energy for charges in a loop is 0.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

For ideal battery neg to positive direction change in Vbat is

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

For ideal battery positive to neg direction change in Vbat is

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

For a resistor change in voltage is

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

load

A

resistor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

loop equaltion with E

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

The current the battery delivers depends on (2)

A

emf of battery (V) and the resistance load

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q
A

The same brightness bc the current us the same in series circuit

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Tell me the energy flow in the circuit to light a bulb

A

battery transfer chemical energy in battery to potential on the charges this then turns into thermal energy on the bulb filaments that make it glow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

power delivered by battery or rate power is transfered to the moving charges formula:

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

what is Pbat?

A

Energy transfered per second from battery’s store of chemicals to moving charges that make up the current

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Thermal energy

formula

A
56
Q

power transfered from current to resistor

A

remember P=IE (three looking thingy) so the “E” in here the the voltage diff in the resistor

56
Q

power transfered from current to resistor

A

remember P=IE (three looking thingy) so the “E” in here the the voltage diff in the resistor

57
Q

The rate at which battery supply energy is —– to the rate at which resistor dissipates energy

A

equal

58
Q

power dissipated by resistor

A
59
Q

The most power will be dissipated by the

A

largest resistor

60
Q

equivalent resistor formula for series

A
61
Q

Ammeter

A

measures the amount of current in a circuit

62
Q

Current formula for a real battery

A
63
Q

terminal voltage of a real battery

A
64
Q

potential difference across terminal of the battery

A
65
Q

short circuit current formula

A
66
Q

Notation X for vectors

A

into page

67
Q

notation . for vectors

A

out of page

68
Q

orientation of the compass with RHR

A

point thumb to current icrection, curl hand, the direction of hand curl is the compass pointing direction of the north pole and direction of the magnectic field

69
Q

magnectic field is weaker at

A

greater distance from the wire

70
Q

Just a pic

A
71
Q

What is this formula for and the variables mean?

A

Magnectic field intensity of a point charge

72
Q

B is —- to the circle drawn about the charg’es line of motion

A

tangent

73
Q

B is —- to the plane of r and v

A

perpendicular

74
Q

B is —- along the line of motion meaning….

Not perpendicular*

A

B is 0

meaning a charge has to be moving to generate magnectic field

75
Q

If there are n moving point charges, the magnectic field formula is

A

VECTOR Sum of all the magnectic field of each point charge

76
Q

RHR of negative charge

A

Use your left hand you dumbass and dont forget this.

77
Q

magnectic field of a very short segment of current *not full long wire

A
78
Q

magnectic field of infinite long striaght wire tell me generally how to find the formula

+Formula :) + w3hat r represents

A
79
Q

Magnectic field of a current loop (in formula)

+ how is this integrated?
+ What does the variables mean?

A
  1. You take original current forumla for magnectic field . Change the r^2 to the z^2+R^2
  2. For some reason you use Cos and find cos through the circule angle and sides
  3. integrate only change in S
80
Q

Magnetic field of current loop of N turns of wire at the center

*derive this lucy…rememeber what happens to Z at the centre?

A
81
Q

What happen to north pole and magnectic field emerging?

A

Repel, south pole attracts
MAGNECTIC FIELD EMERGE FROM NORTH POLE

82
Q

WHats similiar between current look and magnet?

A
83
Q

When Z is much bigger then loop diameter for a current loop

What happens and how can we get this formula?

A
  1. Make R=0
  2. Multiply top and bottom by 2pi
84
Q

distant field of magnectic loop depends on

A

current and area enclosed

85
Q

magnectic dipole momemt

Familiar to point charge dipole moment!!!!!!!!

A
86
Q

On the axis of the magnectic dipole of current loop formula When its very far away*

Similiar to E field of dipole on y axis!

A
87
Q

Magnectic force is greatest at

A

90 degree between B and V

88
Q

force on a negative charge in magnectic field is

how to find

A

use ur left hand

89
Q

Magnectic field and work relationship

+ why?

A

does no work
Because Work= F∙d and force is perpendicular to V in magnectic field so its not in the same plane as d and is always perpendicular and cos90=0

90
Q

Megnectic force directionality

A

perpendicular to displacement which is in direction of velocity

91
Q

kinectic energy after N turns in cyclotron

A
92
Q

Hall effect steady voltage

A
93
Q

Hall voltage (2)

A

V=IB/(tne)

94
Q

Brightness of the bulb is determined by

A

Power

P = I^2R

95
Q

How to caculate questions with internal resistance?

A
  1. FInd current with total R (R+r) with internal resistance added on
  2. Use current to find volt of stuff like bulbs but do not use internal resistance value after u used it to find current
96
Q

Being grounded does not

A

affect the circuit’s behaviour under normal conditions

97
Q

In a grounded wire, the earth

A

is not part of a complete circuit so there is no current in this wire

98
Q

Terminal volatge is the amount of…

A

terminal voltage represents the amount of electric potential energy (voltage) that is available to the circuit outside of (external to) the battery itself.

99
Q

Magnectic materials are

A

attracted to both poles of a magnet

100
Q

What do magnectic field lines tell us?

A
  1. A tangent to a field line is in the direction of the magnectic field
  2. The field lines are closer together where magnectic field strength is larger
101
Q

The magnectic field exert forces on magnectic poles. The force on a north pole is…..the force on a south pole is…..

A
  1. North pole is parallel to B
  2. South pole is opposite of B
102
Q

All charges create….but only moving charges create…

A
  • electric fields
  • magnectic fields
103
Q

Is Magnetic field superposition?

A

Yes

103
Q

Is Magnetic field superposition?

A

Yes

104
Q

Brief me over finding the magnectic field of a string of current

A

Integration is summation!
We need to add up the magnectic field contributions of a vast number of current segments by letting the sum be an integral.

105
Q

Electromagnet

A

a magnet created by a current in a coil of wire

106
Q

In a loop, North pole is the side where the field…

A

emerge

107
Q

uniform magnetic field is only generated in a

A

Solenoid

108
Q

In a solenoid, with many loops along the same axis, the field in the centre is…. and roughly….. whereas the field outside the loop is…

A

1.within the centre is strong
2.and roughly parallel to the axis
3.very close to 0

109
Q

The formula for magnectic field in a solenoid

+ hint: its the formula on formula sheet but it can further simplified

A

Where n=N/L

*Number of turns per unit length

110
Q

magnetic force is always —– to both the velocity and the magnetic field

A

perpendicular

111
Q

magnectic force on particle moving parallel to field=

A

0

aka what u will get on the final if u dont get ur ass tgt

112
Q

2 scenarios where a charge will not have magnectic force:

A
  1. a charge is at rest
  2. charge is moving parallel or antiparallel to magnectic field
113
Q

The force on a negative charge is

A

in the direction opposite of V X B

114
Q

cyclotron motion

A

particle move perpendicular to magnetic field undergoes circular motion at constant speed

115
Q

How is this formula derived?

Radius for cyclotron
A

Since force of cylotron is like the centripetal acceleration of circular motion…..

you equal that force in cyclotron through RHR to centripetal acceleration

116
Q

As the E field in the cyclotron accelerates the proton across the gap it gains the kinectic energy:

A

eV

117
Q

The —- of the cyclotron orbit increases hence the proton follows a—– —-. But the —– also increase so the —– does not change

A

The Radius of the cyclotron orbit increases hence the proton follows a Spiral path. But the Speed also increase so the Frequency does not change

118
Q

What does the E field and Magnectic field do in a cyclotron?

A

E field= provides the accelerating force for protons as they enter the gaps
Magnectic field provides the centripetal acceleration which stays constant as the Magnectic field doesnt change which is why the radius of cylotron gets bigger since the centripetal acceleration stays same but speed increase so its harder to turn.

119
Q

Hall volatge what do you sub for? What do you start with?

youtube version

A

You start with qvB=qE

Sub E as V/s
q cancels
isolate V thats your hall voltage
vBs=HV
Sub velocity as s/Time
Time= (I=Q/t)

120
Q

You start with qvB=qE

Hall volatge what do you sub for? What do you start with?

Textbook version

A

You start with qvB=qE
Sub E as V/s
q cancels
isolate V thats your hall voltage
vBs=HV
Velocity=. J=I/A. J=nevdA/A. Vd= I/Wtne

sub back into original formula

W cancels out

121
Q

magnectic force on a current carrying wire is

Not the formula

A

the net magnetic force on all the charge carrier in the wire

122
Q

magnectic force on a current carrying wire is

Formula+how do u find it? **One not on formula

A

So the basic QVBsintheta but sub V as x/t and make Q/t the current
Plus the formula should have sin theta

123
Q

Tell me about parallel wires and attraction/repulsion

A

parallel wire carrying current in same direction attract eachother. Parallel wire carrying current in opposite direction repel eachother

124
Q

What is direction of magnectic dipole?

A

The direction of μ⃗ is given by a curled-straight right-hand rule: Grasp the coil so that the fingers of your right hand curl around it in the direction of the current; your extended thumb then points in the direction of the dipole moment μ⃗.

125
Q

2 ways to find cylotron motion:

A
  1. K=2 N eV
  2. K=1/2mv^2 sub V as qvb=mv^2/r
126
Q

Faraday’s law

A

There is a current in a coil of wire only if the magnectic field passing through is changing

127
Q

motional emf

+Formula

A

magnetic forces separate the charges and causes a potential diff between ends

*only present if conductor is moving through B fieild

*fromula derived by V=Es and E=vB

128
Q

The induced current given by Ohms law is:

A
129
Q

force needed to pull the induced current wire with constant speed

A

Use current version of force and sub in the current formula found by I=V/R=vlB/R

130
Q

power provided to the current by pulling on the wire is

A

*rate of which energy is added due to pull

131
Q

Magnetic flux

A

measures the amount of streamlines/field passing through the loop of area A if tilted

132
Q

if flux is increasing, the induce current should make it

A

decrease

133
Q

if flux is decreasing, induced current should make it

A

increase (additive to it)

134
Q

the induced current stops as soon as

A

magnet stops moving

Physics 223 (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions