or...
Reset Password Free Sign Up


incorrect cards (0)
correct cards (0)
remaining cards (0)
Save
0:01
To flip the current card, click it or press the Spacebar key.  To move the current card to one of the three colored boxes, click on the box.  You may also press the UP ARROW key to move the card to the Correct box, the DOWN ARROW key to move the card to the Incorrect box, or the RIGHT ARROW key to move the card to the Remaining box.  You may also click on the card displayed in any of the three boxes to bring that card back to the center.

Pass complete!

Correct box contains:
Time elapsed:
Retries:
restart all cards



Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.

  Normal Size     Small Size show me how

Eletromagnetism

QuestionAnswer
Magnetism is a physical property that we cannot sense
a proton in motion is capable of creating a magnetic field
N pole point to S pole of other if 2 bar magnets, suspended in space, were brought together, what would happen
a permanent magnet a lodestone is an example of
an artificial permanent magnet alnico is used in
Iron classified as ferromagnetic material
repel, attract if 2 magnets are brought together, N to N poles will _____, whereas N to S poles will _____.
most magnets are affected by another magnetic field
most magnetic materials retain their magnetic property when broken
a navigational compass has both a N & S pole
Paramagnetism classification of magnetism
at the poles the earth's magnetic field is strongest
laws of magnetism have a similar formulation as Coulomb's law of electrostatics
the forces b/t the poles of 2 different magnets depends on the permeability of matter separation the magnets
physical laws of magnetism require that there be a S pole for ever N pole
both obey the inverse square law magnetism has some properties similar to those of electrostatics
Magnetism is present in some naturally occuring ores
induced perpendicular to the particle motion when a charged particle moves in a stright line, a magnetic field is
Align when iron is fabricated into a magnet, magnetic domains
attracted to the iron when iron is brought near a permanent magnet, the lines of the magnetic field are
principal classication of magnets naturally occuring; electro-; artifically induced permanent
Gravity the physical laws of magnetism are similar to the laws of ___
Magnetism cannot be felt or sensed
a magnetic field exists in atoms with odd numbers of electrons in any shell
magnetic domain is created when a large number of atomic magnets come together with their dipoles aligned
ferromagnetic material the magnetic dipoles are randomly oriented; dipoles lose their randomness when exposed to an external magnetic field
permanent magnets are artificially produced by charging them in the field of an electromagnet
dimagnetic materials are unaffected by a magnetic field; examples - wood, glass, plastic
Alnico is a combination of aluminum, nickel & cobalt; is 1 of the more useful magnets produced from ferromagnetic material; can be permanently magnetized
Electromagnets wire around an iron core. When electric current is conducted through the wire, a magnetic field is created
1 tesla (T)=10,000 gauss (G) SI unit for magnetic flux (T)=
charged particle moves a magnetic field is induced perpendicular to the particle motion
a hydrogen nucleus has an associated magnetic field
electrons in motion known as electricity or electromagnetism
EMF is expressed in units of volts
Oersted the experimental link connecting electric & magnetic forces was discovered by:
a battery is a source of electromotive force
Intensity the principal advantage of an electromagnet over a solenoid is magnetic field
faraday's law an electric current will flow if the conductor is in a changing magnetic field
electric current the term electromagnetic induction refers to the production of
magnetic field electromagnet & bar magnet produce what type of similar field
a changing magnetic field is present given a closed loop of wire with no electron flow, an electric current can be induced if
mutual 2 coils / self 1 coil the principal difference b/t self-induction and mutual induction is that:
changes direction when an AC source is connected to a coil the current flow through the magnetic field
mutual induction occure in 2nd coil if 2 coils are positioned near each other and a varying source of EMF is passed through the 1st coil
a coil of wire will conduct DC relatively unimpeded
in the secondary coil when an electric current is induced by mutual induction, such current flows:
Generator an electromechanical device
magnetic field produced in a transformer is based on mutual induction
source of EMF which of the following is not required for an electric generator?
the commutator ring the main difference b/t AC and a DC electric generator is
alternating pos (+) & neg (-) intensity the electric current produced by an AC generator has:
pulsating & in 1 direction the electric current intensity produced by a DC generator is
source of EMF one difference b/t an electric generator & an electric motor is the
Switch in electric generators & motors the commuator ring acts as a
rotate the anode an induction motor is used in an x-ray machine to
strength, velocity, angle, # of turns the magnitude of induced current in Faraday's experiment depends on 4 factors
mutual & self induction name the 2 laws of electromagnetics (Faraday's Laws)
mutual induction 2 coils placed close together & the 1st coil is supplied with a varying or AC current causes a flow in the 2nd coil. Primary coil - 1st coil; seconday coil - is the coil induced from the 1st coil alternating current (AC)
self induction induction of an opposing EMF in a coil by its own varying magnetic field from AC
secondary voltage in the relationship b/t primary & seconday voltage in a step-up transformer which is greater?
I2R loss; hysteresis loss; eddy current loss 3 principle casues for transformer energy losses
I2R loss aka copper loss; caused by inherent resistance to current flow that is found in all conduction; proportional to square of current; minimized by using low-resistnace
hysteresis loss lagging loss; demagnetizes & remagnetizes the core material; coercivity is the characteristic that requires engergy to carry out this constant reorientation of the magnetic dipoles
eddy current loss currents opposing the cause which produced them; laminating the transformer core reduces this loss
diff b/t AC & DC can be seen by converting the AC (alternating current) to DC (direct current) by replacing the slip rings on an Ac current with a simple device called the communtator ring, which acts like a switch, thus changing the polarity of the contact on the brush w
magnetic field transformers have iron cores in order to intensify the
the transformer changes electrical potential & current into higher or lower intensities
Voltage a transformer "transforms" or changes electric:
step-up transformer a trnsformer with a tuns ratio greater than I is:
closed-core the transformer that resembles a square donut is called an ____ transformer.
turns ratio is secondary windings / primary windings
Autotransformer contains a single winding to serve as both primary & secondary coils
magnetic field produced if DC is applied to the primary coil of a transformer
rectifier
converts AC to DC
thermionic emission refers to electron emission from a heated source
filament
is a component of a tube-type of rectifier
tube rectifier/vacuum-tube diode, electron flow is from cathode to anode only when the anode is connected to a positive voltage with respect tot eh cathode
circuit containing a solid-state diode electrons will be permitted to flow in one direction but not the other
Magnetism is one of the fundamental forces. When a charged particle is in motion a magnetic force field perpendicular to the motion will be created.
Electromagnets is a temporary magnet produced by a moving electric current
diff b/t electron flow & conventional current flow
electron flow is actually from negative to positive poles while conventional electric current is described as going from positive to negative poles.
thumb pointing movement of conductor
index finger magnetic lines of force field
middle/other finger current or electron flow
3 ways induce electromagnetic current flow in a conductor 1- move the conductor through a stationary, unchanging-strength magnetic field; 2- move magnetic lines of force through a stationary conduction with an unchanging-strenght magnetic fiels; 3- vary the magnetic flux strength from a stationary magnet through
4 factor controlling strength of electromagnetically induced current 1- the strength of the magnetic field; 2- the speed of the motion b/t lines of force & conductor; 3- the angle b/t the magnetic lines of force & the conductor; 4- the number of turns in the conduction coil
diff generator & motor generator converts mechanical energy to electrical energy & a motor converts electrical energy to mechanical energy. (if the power goes out we can use a generator (mechanical) to have lights (electricity); motor battery (electrical) to start motor (mechan
function of a transformer a divice that operates on alternating current to change electricity from a primary voltage to a secondary source. It utilizes the principles of electromagnetic mutual induction with the application of Ohm's Law.
transformer law Vs/Vp = Ns/Np; V= potential difference in volts; N= # of turnes of wire in the coil; p= primary coil; s=secondary coil
Autotransformer used to vary the incoming line voltage to an appropriate level for the high voltage step-up transformer.
Diode creates an electrical "one way street" by permitting electrons to flow easily in 1 direction while offering a high resistance to movement in the other direction.
Rectification the process by which alternating current is changed to pulsating direct current
componets for full-wave rectified circuit 4 rectifiers in a bridge circuit are necessary
in a transformer is based on mutual induction
source of EMF
which of the following is not required for an electric generator?
the commutator ring
the main difference b/t AC and a DC electric generator is
alternating pos (+) & neg (-) intensity
the electric current produced by an AC generator has:
pulsating & in 1 direction
the electric current intensity produced by a DC generator is
source of EMF
one difference b/t an electric generator & an electric motor is the
Switch
in electric generators & motors the commuator ring acts as a
rotate the anode
an induction motor is used in an x-ray machine to
strength, velocity, angle, # of turns
the magnitude of induced current in Faraday's experiment depends on 4 factors
mutual & self induction
name the 2 laws of electromagnetics (Faraday's Laws)
mutual induction
2 coils placed close together & the 1st coil is supplied with a varying or AC current causes a flow in the 2nd coil. Primary coil - 1st coil; seconday coil - is the coil induced from the 1st coil alternating current (AC)
self induction
induction of an opposing EMF in a coil by its own varying magnetic field from AC
secondary voltage
in the relationship b/t primary & seconday voltage in a step-up transformer which is greater?
I2R loss; hysteresis loss; eddy current loss
3 principle casues for transformer energy losses
I2R loss
aka copper loss; caused by inherent resistance to current flow that is found in all conduction; proportional to square of current; minimized by using low-resistnace
hysteresis loss
lagging loss; demagnetizes & remagnetizes the core material; coercivity is the characteristic that requires engergy to carry out this constant reorientation of the magnetic dipoles
eddy current loss
currents opposing the cause which produced them; laminating the transformer core reduces this loss
diff b/t AC & DC
can be seen by converting the AC (alternating current) to DC (direct current) by replacing the slip rings on an Ac current with a simple device called the communtator ring, which acts like a switch, thus changing the polarity of the contact on the brush w
magnetic field
transformers have iron cores in order to intensify the
the transformer
changes electrical potential & current into higher or lower intensities
Voltage
a transformer "transforms" or changes electric:
step-up transformer
a trnsformer with a tuns ratio greater than I is:
closed-core
the transformer that resembles a square donut is called an ____ transformer.
turns ratio is
secondary windings / primary windings
Autotransformer
contains a single winding to serve as both primary & secondary coils
magnetic field produced
if DC is applied to the primary coil of a transformer
rectifier
converts AC to DC
thermionic emission refers to
electron emission from a heated source
filament
is a component of a tube-type of rectifier
tube rectifier/vacuum-tube diode, electron flow is
from cathode to anode only when the anode is connected to a positive voltage with respect tot eh cathode
circuit containing a solid-state diode
electrons will be permitted to flow in one direction but not the other
Magnetism
is one of the fundamental forces. When a charged particle is in motion a magnetic force field perpendicular to the motion will be created.
Electromagnets
is a temporary magnet produced by a moving electric current
diff b/t electron flow & conventional current flow
electron flow is actually from negative to positive poles while conventional electric current is described as going from positive to negative poles.
thumb pointing
movement of conductor
index finger
magnetic lines of force field
middle/other finger
current or electron flow
3 ways induce electromagnetic current flow in a conductor
1- move the conductor through a stationary, unchanging-strength magnetic field; 2- move magnetic lines of force through a stationary conduction with an unchanging-strenght magnetic fiels; 3- vary the magnetic flux strength from a stationary magnet through
4 factor controlling strength of electromagnetically induced current
1- the strength of the magnetic field; 2- the speed of the motion b/t lines of force & conductor; 3- the angle b/t the magnetic lines of force & the conductor; 4- the number of turns in the conduction coil
diff generator & motor
generator converts mechanical energy to electrical energy & a motor converts electrical energy to mechanical energy. (if the power goes out we can use a generator (mechanical) to have lights (electricity); motor battery (electrical) to start motor (mechan
function of a transformer
a divice that operates on alternating current to change electricity from a primary voltage to a secondary source. It utilizes the principles of electromagnetic mutual induction with the application of Ohm's Law.
transformer law
Vs/Vp = Ns/Np; V= potential difference in volts; N= # of turnes of wire in the coil; p= primary coil; s=secondary coil
Autotransformer
used to vary the incoming line voltage to an appropriate level for the high voltage step-up transformer.
Diode
creates an electrical "one way street" by permitting electrons to flow easily in 1 direction while offering a high resistance to movement in the other direction.
Rectification
the process by which alternating current is changed to pulsating direct current
componets for full-wave rectified circuit
4 rectifiers in a bridge circuit are necessary
Created by: Sassyconch on 2008-11-10



Copyright ©2001-2014  StudyStack LLC   All rights reserved.