Physics Test 1

Front 1

The positively charged items of an atom are called

Back 1

protons

Front 2

A copper wire would be classified electrically as

Back 2

a conductor

Front 3

Which is a method for producing a charged object

Back 3

-Friction
-Contact
-Induction

Front 4

What is the direction of an electric field?

Back 4

- away from + charges
- Toward - charges

Front 5

If a metal has stationary excess negative charge, then

Back 5

- the metal is an equipotential volume
- The electric field is perpendicular to the metal

Front 6

Electical potential difference is also called

Back 6

voltage

Front 7

If the current through a resistor is doubled, what else associated with the resistor is doubled?

Back 7

voltage

Front 8

The reistance of a piece of wire depends upon

Back 8

- its length
- its cross-sectional area

Front 9

Which equation is incorrect?

Back 9

R=(pA)/L

Front 10

Which is a unit of charge?

Back 10

Coulomb

Front 11

Nucleus is positively charged. Must be full of...

Back 11

protons

Front 12

How much heavier is a proton than an electron?

Back 12

2000 e's = 1 p

Front 13

Three ways to make a charge

Back 13

1) Friction
2) Contact
3) Induction

Front 14

Friction (charge)

Back 14

one material of one kind against another kind of material

Front 15

law of conservation

Back 15

total charge after = total charge before

The total charge in the universe is zero

Front 16

Contact (charge)

Back 16

When a neg charged item comes into contact with a neutral or positive.

Front 17

Induction

Back 17

Using a third material between the object with negative charge and the object with neutral or positive charge

Front 18

Conductors

Back 18

Normally metals, allows e-'s to flow through it.

- Valence electrons can break away from atom and move to another

Front 19

Insulators

Back 19

Do not allow e-'s to flow through it.

- Electrons don't split away from the atom

Front 20

Semiconductors

Back 20

usually materials like silicon and germanium (from Group III mixed with Group V)

- Intermediate resistance that changes with temperature

Inductors and conductors are not temperature dependent

Front 21

Glass rod with silk demo

Back 21

- charge is different on glass rod and metal
- Glass rod is positive, silk is negative
- Neg charges are the ones that move.

Front 22

Coloumb's law

Back 22

F=kq1q2/r^2

- True only if objects are spherical or same distance apart.

Front 23

Electrically charged comb and paper demo. What did it prove?

Back 23

Just because an object is neutral doesn't mean that there will not be a force between them.

Front 24

Charges sprayed onto a sheet of paper.

Back 24

In most cases the force of the electric field is perpendicular to charge.

Front 25

Electric field equation

Back 25

E=F/q

Front 26

k (coulomb's constant)

Back 26

8.99 x10^9 N*m^2/C^2

Front 27

Eo

Back 27

8.85 x 10^-12 C^2/N*m^2

Front 28

Important derivation for charge in between two objects with different charges

Back 28

E=kq1/r^2

Front 29

Does the size of an object reflect change in charge?

Back 29

No

Front 30

The futher away from an object, the electron field line is pointed...

Back 30

toward the center

Front 31

center of charge =

Back 31

center of gravity

Front 32

Water as a polar molecule

Back 32

Water will rotate around its center

- a microwave oven sends alternating E- field in order to excite the molecules.

Front 33

If charge is sprayed on a sheet, what happens?

Back 33

charge will spread evenly on the sheet

Front 34

When you put charge on a metal, the ____ charge goes on the ________

Back 34

negative, outside.

Front 35

If touched with a negative charged object....

Back 35

the charge will distribute through the object.

- Next the charge will move toward the outside of the object

Front 36

If an object is narrow at one point, it will have a _______ charge due to ______ in the area.

Back 36

stronger; concentration

Front 37

When in a tunnel...

Back 37

the charges in an electric field cancel each other out.

Front 38

An object moved horizontally has not had work performed on it.

Back 38

Example, an object that should be falling down from a height is moved horizontally = no work.

Front 39

Equation for voltage

Back 39

V = -Ed

Front 40

Voltage

Back 40

the difference in electric potential

Front 41

Direction of electric field lines is from ____ voltage to _____ voltage

Back 41

high, low

Front 42

Electric for amount of q is given by

Back 42

F = qE

Front 43

Direction of F on q is in the same direction as E when q is _____

Back 43

positive

Front 44

work done by electric force to move a charge from V1 to Vf is given by

Back 44

We = -qV

Front 45

We will be positive when

Back 45

positive charge goes in direction of E

- (from high to low V)

Front 46

If We is positive, Fe will cause the charge to _______

Back 46

speed up

Front 47

We = 0 when +q moves along _________ surface

Back 47

equipotential

Front 48

We is negative when +q moves ______ direction of E

Back 48

opposite

Front 49

Electric field from one uniform sheet of charge, close to the MIDDLE of the sheet is given by....

Back 49

E = (sigma)/2Eo

sigma = Q/A

Front 50

Electric field from charge on the surface of a metal, near the outside surface is given by

Back 50

E = (sigma)/Eo

- sigma is evaluated at the ready surface.

Front 51

All points inside the metal are ______

Back 51

zero.

Front 52

Death of a battery

Back 52

When a battery cannot give e-'s to the negative side and pull e-s's from the positive side.

Front 53

Capatance

Back 53

Co=EoA/d

Front 54

E is proportional to

Back 54

charge

Front 55

charge is proportional to

Back 55

voltage