Exam 1 - Shit I do not know

2 parallel sheets with equal and opposite charges

capacitor

what does a capacitor do

sets up a strong,. uniform electric field in a small region. inside is strong, outside is almost 0

what doesn’t matter for a capacitor?

the distance in between the plates (z)

Q/A

surface charge density (sigma)

Insulator

material where electrons are bound to atoms so charge cannot more freely. atoms turn into dipoles

Insulator examples

plastic, glass, rubber, dry air

z meaning

distance from source to point (“how far am i from the object”)

s meaning

how big is the gap that the objects built wirh

what is an ok ratio to use « for

around 1/10 or 0.1

infinite rods: what is Q/L

lamda = Q/L = linear charge density

which direction is the rod on x axis pointing

y axis, so up and down

insulator means what

the charge will stay in the same places

in a shell, do you take the distance from the center or from the closest point to the shell

center

what does the “zero charge inside shell” apply to

ONLY its own charge, not external charges

In equilibrium, there is no net flow of mobile charged particles inside a conductor T/F

True

The net electric field at any location inside a block of copper is zero if the copper block is in equilibrium T/F

True

The net electric field inside a block of aluminum is zero under all circumstances - T/F

False, only in eq

If the net electric field at a particular location inside a piece of metal is not zero, the metal is not in equilibrium

True

The electric field from an external charge cannot penetrate to the center of a block of iron. T/F

False,

Conductors - where is the charge in equilibrium

E = 0 everywhere inside regardless of the external charges. All excess charge is on its surface

Conductors - where is the charge NOT in equilibrium

Doesn’t apply, can still be not in EQ

types of conductors

metal

relation between capacitors and conductors

Capacitor plates are conductors in equilibrium, separated by an insulator

how to find the potential energy (U)

sum over EVERY PAIR

When the reference point is at infinity for V, (change in electric potential)

1/r_i becomes 0, because initial is infinity

Electric Potential Variable

V, units volts

Potential Energy variable

U (measured in J aka Nm)

volts units

(N*m)/C