Electrostatics and Magnetism .

Question 1

What is the SI unit for charge?

Answer 1

Coulomb .

Question 2

what is the fundamental unit charge of electrons and protons?

Answer 2

1.6 x 10^-19

Question 3

What are conductors

Answer 3

they allow free and uniform passage of electrons when charged

Question 4

What are insulators?

Answer 4

resist the movement of charge and will have localized areas of charge that do not distribute over the surface of the material

Question 5

What is coulomb’s law?

Answer 5

gives the magnitude of the electrostatic force vector between two charges. The force vector always points along the line connecting the centers of the two charges.

Fe = kq1q2/r^2

Question 6

Every charge a…?

Answer 6

an electric field, which can exert forces on other charges.

Question 7

What is an electric field?

Answer 7

the ratio of force that is exerted on a test charge to the magnitude of that charge.

E = Feq = kQ/r^2

Question 8

What are field lines?

Answer 8

representation of electric field vectors, they radiate outward form positive source charges and radiate inward to negative source charges. Positive test charges will move in the direction of field lines, negative charges go opposite.

Question 9

What is the electrical potential energy?

Answer 9

it is the amount of work required to bring the test charge from infinitely far away to a given position in the vicinity of a source charge. It will increase when two like charges move toward each other or when two opposite charges move further apart. It will decrease when two opposite charges move toward each other or when tow like charges move further apart.

U = kQq/r

Question 10

What is electrical potential?

Answer 10

is the electrical potential energy per unit charge. Different points in the space of an electric field surrounding a source charge will have different electrical potential values.
From electrical potential energy: V=U/q .
From source charge: V= kQ/r

Question 11

What is potential difference (aka voltage)?

Answer 11

the change in electrical potential that accompanies the movement of a test charge from one position to another. Potential difference is a path independent and depends only on the initial and final positions of the test change. The units for both electrical potential and voltage are volts.
ΔV = Vb -Va = Wab/q

Question 12

In what direction will test charges move?

Answer 12

spontaneously in the direction that results in decrease of their electrical potential energy. Positive test charges move from high to low potential. Negative charges move from low to high potential.

Question 13

Equipotential lines

Answer 13

designate the set of points around a source charge or multiple source charges that have the same electrical potential. they are always perpendicular to electric field lines. work will be done when charges moves form one line to another; work is independent of the pathway. No work is done when a charge moves from a point on an equipotential line to another point on the same line.

Question 14

Electric dipole

Answer 14

two charges of opposite sign separated by a fixed distance d generate an and electric dipole. In an external electric field, an electric dipole will experience a net torque until it is aligned with the electric field vector. the field will no induce any translational motion in the dipole regardless of its orientation with respect to the e field vector.

Question 15

Magnetic fields

Answer 15

created by magnets and moving charges. Th SI unit is the tesla.

Question 16

Diamagnetic materials

Answer 16

possess no unpaired electrons and are slightly repelled by a magnet.

Question 17

Paramagnetic materials

Answer 17

possess some unpaired electrons and become weakly magnetic in an external magnetic field.

Question 18

Ferromagnetic materials

Answer 18

possess some unpaired electrons and become strongly magnetic in an external magnetic field.

Question 19

Poles of magnets .

Answer 19

has a North and south, Field line point from north to south.

Question 20

magnetic fields in wires

Answer 20

create magnetic field that are concentric circles around the wire.

Question 21

External magnetic fields

Answer 21

exert forces on charges moving in any direction except parallel or antiparallel to the field.

Question 22

Point charges and circular motion

Answer 22

may undergo uniform circular motion in a uniform magnetic field wherein the centripetal force is the magnetic force acting on the point charge.

Question 23

How is the direction of magnetic force on a moving charge or current carrying wire determined?

Answer 23

by using the right hand rule

Question 24

What is the Lorentz force?

Answer 24

is the sum of the electrostatic and magnetic forces acting on a body,

Question 25

Electrical potential near a dipole

Answer 25

V=kqd/r^2 cosΘ

Question 26

Dipole moment equation

Answer 26

p=qd

Question 27

Electric field on the perpendicular bisector of a dipole

Answer 27

E =1/4πe0 x P/r^3

Question 28

torque on a dipole in an electric field

Answer 28

t= pE sin Θ

Question 29

Magnetic field from a straight wire

Answer 29

B= u0I/2πr

Question 30

Magnetic field from a loop of wire

Answer 30

Bu0I/2r

Question 31

Magnetic force on a moving point charge

Answer 31

Fb = qvBsin Θ

Question 32

Magnetic force on a current-carrying wire

Answer 32

FbILBsin Θ

Question 33

consta k is

Answer 33

Coulomb’s constant/ electrostatic constant

1/4πe0 = 8.99 x 10^9 N m^2/C^2 .

Question 34

What is e0

Answer 34

permittivity of free space

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

Question 35

What is variable Q

Answer 35

source charge which actually creates the field

Question 36

what is q

Answer 36

the test charge, charge placed in electric field.

Question 37

what is u0

Answer 37

Permeability of free space

4π x 10^ -7

Question 38

right hand rule

Answer 38

thumb- velocity and direction of flow
fingers-field lines
palm- positive force
back hand- negative force