Physics Chapter 6 & 7

Front 1

Charge is quantized meaning it can't be split up, what is the formula for finding the charge on atom?

Back 1

q = (+/-(e))*n

Front 2

What is the value for the two constants e and k

Back 2

K= 9e9
e= 1.6e-19

Front 3

When the columb equation has a positive value, do the charges attract or repel?

Back 3

They repel

Front 4

How many charges are required when making an electric field

Back 4

One charge (source charge)

Front 5

If you have a positive electric field, then what direction is the electric field and what is the equation for the electric field?

Back 5

The equation for electric field is
E=K*(Q)/r^2
The E means the source charge that created the electric field is positive and the electric field will point away from the charge

Front 6

When looking electric field lines, where is the electric field the strongest?

Back 6

Where the lines converge together

Front 7

What is the equation to find the force created by an electric field on a charge

Back 7

F=qE

Front 8

What changes the acceleration of a particle in an electric field

Back 8

The change in electric field

Front 9

In electric field equations if you have a negative force, what does this tell you about the direction of the force in relevance to the electric field

Back 9

The force points opposite the electric field

Front 10

What is a scalar quantity in electrostatics and what is different between electric field and electric potential

Back 10

Electric potential and the electric potential is the same everywhere at the same distance because this is scalar, while electric field is not the same at a r because it involves direction

Front 11

What does the sign on the electric potential correspond to and what is the equation

Back 11

The equation is Potential = k(Q/r)
The sign corresponds to a negative or positive charge

Front 12

What are the units for electric potential?

Back 12

The units are volts (J/C)

Front 13

What is the equation for finding the change in electric potential energy

Back 13

PE = q*(change in potential difference)

Front 14

How can one find the kinetic energy and potential energy in an charge

Back 14

The work equals = -Delta PE
Delta KE= -Delta PE

Front 15

If I say a charge spontaneously acceleartes what does this mean

Back 15

The charge is gaining kinetic energy

Front 16

What is 1ev

Back 16

This simply means that an electron * 1 potential difference so.... 1eV=1.6e-19

Front 17

The superposition principle is used in electric potential but what is different when comparing to the other electric forces

Back 17

You just add up the electric potetential there is no vectors

Front 18

Why can't we use W=Fd in electric and what work equation is used to move one charge and which is used to move total charge?

Back 18

Because force isn't constant
Total charge= W=.5QV
One charge=potential difference*charge

Front 19

Are equipotentials always perpendicular or parrallell to electric field lines,

Back 19

perpendicular

Front 20

The eqaution for work in electric is corresponding to what

Back 20

The work equals negative potential energy

Front 21

What is an mnemonic for statements involving electric potential

Back 21

Protons-heavy
Electrons-light

Rocks fall (lower potential)
Helium rises(higher potential)

Front 22

What is current

Back 22

The net movement of charge. I=Q/t

Front 23

What is drift velocity

Back 23

The movement of electrons. If THERE IS drift velocity there is a current

Front 24

What creates current

Back 24

Net movement of charge

Front 25

What is the formula for resistivity

Back 25

R=resistivity*(L/A)
A-cross sectional area

Front 26

Does resistivity increase or decrease with temperature

Back 26

Increase

Front 27

How do you add resistors in parralel and in series. And what is important about adding resistors in parallel,

Back 27

In series you add R1+R2...and so fourth

In a parrallel you add (R1*R2)/(R1+R2)

In a PARALLEL YOU CAN ONLY ADD TWO RESISTORS AT A TIME

Front 28

What is the convention for saying the flow of a current

Back 28

The flow of a current is always the direction that positive charges will flow

Front 29

Often the question is what remains constant in series and parrallel, describe how current and voltage are changed or the same in either one

Back 29

Series= Current the same, V may change if resistors change

Parrallel-V the same, I may change if resistors change

Front 30

What are the two kirchoff laws

Back 30

The voltage that came from the battery, when you sum the whole circuit will equal this value

The current passing the battery, will be the sum of the current pass through all indv. resistors in the combination.- page 252

Front 31

What is the formula for power dissapated by the resistor and power supplied by the battery equation and how can they relate

Back 31

P=IV-battery
P=I^2*R-for each resistor

THe sum of the resistor will equal the power by the battery

Front 32

What is the equation to find energy in a circuit

Back 32

Remember-power=energy/time

Energy = time*power

Front 33

What is the equation to find terminal voltage

Back 33

V=EMF-Ir= if battery supplies circuit

V=emf+Ir- if circuit is supplying current to the battery

Front 34

When does the current stop with a capcitor

Back 34

When the capacitor's voltage equals the voltage of the battery

Front 35

What is the equation for charge on the capacitor

Back 35

Q=V*C

Front 36

What affecs capacitance

Back 36

Distance between the parrallel plates and the size of the plates

Front 37

What is the equation for capacitance

Back 37

C = e*(A/d)
eo-8.85e-12

Front 38

What is very important to remember about capacitance

Back 38

Capacitance is a constant the only thing that changes capacitance is the area of the plate and the distance between the plates

Front 39

What is the equation to find electric field on parallel plate with capacitor

Back 39

V=Ed

Front 40

Is there work used when moving electrons to a positive charge

Back 40

Yes, the work done by the voltage source. Work against the electric field of the capacitor

Front 41

What is the formula for finding Potential energy in a capacitor

Back 41

PE=.5*Q*V

Front 42

Describe what happens as one discharges a capacitor

Back 42

The capacitor will first discharge quickly and then will level off slowly

Front 43

What does the precesnce of a dielectric do to the capacitance

Back 43

It will increase

Front 44

What happens when a dielectric is placed in between a capacitor plates after the battery as been removed?

Back 44

The Q will remain constant!!!!

Front 45

What happens to the voltage as a capacitor is being charged with a battery and a dielectric is placed in between?

Back 45

The V will remain constant

Front 46

Explain dielectric breakdown

Back 46

The dielectric increases the maximum of an electric field so electrons can't go throgh (air) to the positive plate. The dielectric prevents polarization.

Front 47

What are the equations for Vrms and Irms

Back 47

Vrms= Vmax/(2)^1/2
Irms = Imax/(2)^.5

Front 48

How are magnetic fields created?

Back 48

They are created by moving electric charges

Front 49

What is the equation to determine the magnetic force that a charge will feel

Back 49

F=velocity of charge*charge*B

Front 50

How does one find the magnitude of force of a magnetic field

Back 50

F= abs(q)*v*Bsin(theta)
The angle is between the v and B

Front 51

Is the magnetic field force perpendicular or parallel to the v AND magnetic field lines

Back 51

Both are perpendicular to force

Front 52

Describe how to use the right hand rule

Back 52

USE YOur left hand for negative charges

Thumb is velocity
Fb is your palm
Fingers are B

Front 53

Do magnetic forces do work

Back 53

No, because always perpendicular to the velocity of charge and this means they can't change kinetic energy

Front 54

What can magnetic forces change speed or direction

Back 54

Direction

Front 55

How do you find the radius of of the circular path of a proton, (the centripetal force)

Back 55

F= mv^2/r
qvB=mv^2/r

Front 56

When a wire creates a magnetic field, what makes the magnetic field stronger?

Back 56

Being closer to the wire and increasing the current

Front 57

In a solenoid, where is the magnetic field the greatest

Back 57

In the middle, center of axis. Line through the bullseye

Front 58

How does magnetic field correspond in a solenoid

Back 58

B is proportional to I* (N/L)

Front 59

What equation can show how magnetic field is related to I and r in a wire

Back 59

B is proportional to I/r

Front 60

What is the units for Tesla

Back 60

Tesla equals N/A*m

Front 61

What is dependant only on shape, size and material, V, I or R

Back 61

R

Front 62

Besides the potential energy equation= 1/2QV, what is another eqation to determine energy through a capacitor

Back 62

.5CV^2

Front 63

Besides the E= kq/r^2, what is another equation to find electric field?

Back 63

E= Volts/meter = 1 V=1J/C, SO 1 V/m = 1N/C