RT 205 Electromagnetic

Question 1

Electrostatics

Answer 1

The branch of physics that deals with the force exerted by a static

Question 2

Electric Field

Answer 2

An effect produced by an electric charge that exerts a force on charged objects in its vicinity

Question 3

Fundamental Force

Answer 3

Material with the ability to attract iron

Question 4

Orbital magnetic moment

Answer 4

Magnetic field perpendicular to the motion of a charged particle

Question 5

Spin magnetic moment (Electron spin)

Answer 5

Magnetic effect established by electrons spinning on their axis

Question 6

Magnetic Resonance Imaging

Answer 6

Disruption of the axial spinning and energy released as domains reorient themselves

Question 7

Magnetic dipoles (aka Magnetic domains)

Answer 7

Groups of atoms with their net magnetic field moving in the same direction
(Theorized: about 10^15 atoms make up a dipole)

Question 8

Magnetic Field (aka Lines of force (flux))

Answer 8

Force fields formed when magnetic dipoles orient to create a magnet

Question 9

Lines of force always flow from ________ to _________ outside the magnet, and flow from ________ to _________ inside the magnet.

Answer 9

Flow from north to south outside the magnet

Flow from south to north within a magnet

Question 10

SI unit: Lines of Force

Answer 10

Weber (Wb)

Question 11

A magnet that is moved in space near a second magnet experiences a _____________.

Answer 11

Magnetic Field

Question 12

The strength of the magnetic field is ________ when lines are closer, and ________ when they are farther apart.

Answer 12

Great when lines are closer, and weak when farther apart

Question 13

Magnetic flux=

Answer 13

Field strength/area

Measure in Tesla (T) and Gauss (G)

Question 14

1 Tesla= 10,000 G= 1 Wb/m^2

Answer 14

Blank

Question 15

The earth’s magnetic field thought to originate with moving charges = ________T or _______G

Answer 15

= 0.0001 or 1 G

Question 16

Classifications of Magnets
Iron oxide (magnetite) remains on earths magnetic fields

Answer 16

Natural

Question 17

Classifications of Magnets
Manufactured from steel alloy
ex. Aluminum, nickel, cobalt

Answer 17

Artificial permanent

Question 18

Classifications of Magnets

Temporary magnet produced by moving electric current (Electron current creates magnetic field)

Answer 18

Electromagnets

Question 19

Laws of Magnetism

Repulsion- attraction

Answer 19

Like poles repel,Unlike poles attract

Like lines of force repel, Unlike lines of force attract

Question 20

Laws of Magnetism

Inverse square law

Answer 20

Force between two magnetic fields directly proportional to product of their magnitudes and inversely proportional to square of distance between them.

Question 21

Ease with which a material can be magnetized

Answer 21

Permeability

Question 22

Ability of a material to stay magnetized

Answer 22

Retentivity

Question 23

Ferromagnetic

Answer 23

Material with high magnetic permeability
Imposes little resistance to orientation in presence of a magnetic field
(Ex. Iron, Steel, Nickel)

Question 24

Paramagnetic

Answer 24

Materials with a weak attraction to magnetic fields
-Low Permeability
(Ex. Platinum, Aluminum, MRI Contrast)

Question 25

Diamagnetic

Answer 25

Weak form of magnetism exhibited only in presence of magnetic field (Ex. Beryllium, bismuth, lead, water)

Question 26

Nonmagnetic

Answer 26

Materials not affected by a magnetic field and cannot be magnetized (Ex. Wood, Glass, Plastic)

Question 27

A device that stores energy and makes it available in an electrical form

Answer 27

Battery

Question 28

A device for creating or storing electrical energy composed of several similar (usually identical) cells that are connected together

Answer 28

Electrical battery

Question 29

Electrical cell

Answer 29

A single such unit, possibly one cell in a battery of multiple cells or possibly the entire device

Question 30

1V=__ Joule/Coulomb

Answer 30

1 V= 1 Joule/Coulomb

Question 31

A coil consisting of a series of loops, and serves to increase the flux density

Answer 31

Solenoid coil

Question 32

Electromagnetic relay

Answer 32

Similar to circuit breakers | - Protect Technologists from high voltage when flowing

Question 33

Three ways to create motion between lines of force and a conductor

Answer 33

1. Magnetic field 2. Conductor 3. Relative motion

Question 34

Methods to Induce a Current 1. Move conductor through stationary unchanging strength magnetic field 2. Move magnetic lines of force across conductor with unchanging strength magnetic field 3. Vary strength of stationary magnetic field through conductor

Answer 34

Blank

Question 35

Four Factors of Faraday's Law

Answer 35

1. The strength of the magnetic field 2. The velocity of the magnetic field as it moves past the conductor 3. The angle of the conductor to the magnetic field (lines of flux) 4. The number of turns in the conductor

Question 36

Lenz's Law

Answer 36

An induced emf generates a current that induces a counter magnetic field that opposes the magnetic field generating the current

Question 37

Mutual Induction

Answer 37

The production of an electromotive force (emf) or voltage in an electric circuit caused by a changing magnetic flux in a neighboring circuit.

Question 38

Self-Induction

Answer 38

Property whereby an electromotive force is induced in a circuit by a variation of current in the circuit itself.

Question 39

Opposition to the flow of AC current produced by an inductor. (Measured in Ohms and varies in direct proportion to frequency)

Answer 39

Inductive Reactance