Electricity and Magnetism

Question 1

unit of charge

Answer 1

coulombs

Question 2

current run….

Answer 2

in the opposite direction of electrons

Question 3

Universal Law of Conservation of Charge

Answer 3

every time a negative charge in created, a positive charge is created, and vice versa

Question 4

Coulomb’s Law

Answer 4

F = Kq_1q_2/r^2

magnitude of force of repulsion or attraction between 2 charged objects

Question 5

both gravitational and electric forces change inversely with…

Answer 5

the square of the distance between the centers of mass or charge

Question 6

field

Answer 6

some type of distortion or condition in space that creates a force on a charge, or mass if gravitational field, or magnet if magnetic field

Question 7

lines of force

Answer 7

represent a field, point in direction of field (positive to negative for electric fields), closer lines = stronger field

Question 8

field lines point ____ for electric fields

Answer 8

positive to negative

Question 9

electric field from point charge, E =

Answer 9

E = kq_1/r^2

Question 10

force on charge in electric field=

Answer 10

F = Eq

Question 11

potential energy of charge in E field=

Answer 11

force x displacement

U = Eqd

Question 12

electric potential energy from point charge =

Answer 12

U = kq_1q_2/r

Question 13

voltage

Answer 13

potential for work by an electric field in moving any charge from one point to another
V = Ed
units: J/C

Question 14

voltage due to point charge

Answer 14

V = kq_1/r

Question 15

equipotential surfaces

Answer 15

all points on surface are same voltage

Question 16

electric dipole

Answer 16

created by two opposite charges with equal magnitude

Question 17

resistivity

Answer 17

quantitative measure of substance’s resistance to flow of charge

Question 18

resistance (R)

Answer 18

quantitative measure of an object of a particular shape and size to resist the flow of charge, in ohms

Question 19

Ohm’s Law

Answer 19

V = iR

Question 20

Kirchoff’s rule

Answer 20

amount of current flowing into any node must be the same amount that flows out
voltage around any path in a circuit must sum to zero

Question 21

EMF

Answer 21

the voltage on a battery

Question 22

capacitor

Answer 22

to temporarily store energy in a circuit in the from of separated charge

Question 23

parallel plate capacitor

Answer 23

two plates fade from conductive material separated by a very small distance, one plate positive other plate same amount of negative charge

Question 24

capacitance

Answer 24

ability to store charge per unit voltage, something with high capacity can store a lot of charge at low voltage
C = Q/V

Question 25

energy stored by any shape capacitor

Answer 25

U = 1/2QV
U = 1/2CV^2
U = 1/2Q^2/C

Question 26

dielectric constant, k

Answer 26

the substance between the plates of a capacitor

must be an insulator, acts to resist the creation of an electric field and allows the capacitor to store more charge

Question 27

resistors in series

Answer 27

Reff = R1 + R2 + R3…

Question 28

resistors in parallel

Answer 28

1/Reff = 1/R1 + 1/R2…

Question 29

capacitors in parallel

Answer 29

Ceff = C1 + C2 +….

Question 30

capactiors in serioes

Answer 30

1/Ceff = 1/C1 + 1/C2.

Question 31

electrical power

Answer 31

P = iV
P = i^2*R
P = V^2/R

Question 32

direct vs. alternating current

Answer 32

direct = net movement  of e-s is in one direction around circuit 
alternating = created by oscillating e-s back and forth in simple harmonic motion

Question 33

voltage and current for ac curernts

Answer 33

root mean square
Vrms = sqrt(2)/2Vmax
Irms = sqrt(2)/2I max

Question 34

magnetic field strength measured in….

Answer 34

units of tesla, T

Question 35

static electric field produces ____ force on a magnet, static magnetic field produces ____ force on an electric charge

Answer 35

NO

Question 36

changing an electric field induces a _____, and changing a magnetic field induces an _____

Answer 36

magnetic field, electric field

Question 37

force on a charge moving through a magnetic field

Answer 37

F = qvBsin(theta) 
theta = angle between magnetic field and velocity of the charge

Question 38

a charged particle moving through a magnetic field….

Answer 38

will be forced into a curved path