WorksheetsMagnetism
Total questions: 100
Worksheet time: 50mins
Who was the one who discovered that current produces a magnetic field ?
Oersted
len'z
Michael faraday
How can a magnet generate current ?
moving bar magnet back and forth in a coil
Moving coil of wire around magnet
Moving and then stop moving the bar magnet in a coil
Did Oersted discover that magnetic field could produce current ?
Yes
No
Who was the one who discovered that magnetic field could produce current ?
Faraday
Oersted
Faraday discovered that current produces magnetic field true or false
True
False
Oersted discovered that magnetic field produce current
True
False
An electric current can be generated in in a wire when ___________-
part of wire cuts MF lines
when charges accelerates
when they are perpendicular
Can Field line also cut a segment of wire moves through stationary MF
True
False
How can field lines be cutten?
Wire moves through statinary MF
MF approaches near wire or strength Of MF changing
Non Of the above
The direction of current induced in wire moving througgh a MF DEPEND ON
direction of wire
Direction of MF
perpendiculr 90 degrees
When motion stops , what happens ?
moves but perpendicular
Current stops
All of the above
Strength of MF changes around wire
True
field lines can be cut too
False
cannot be cutten too
Define Electromagnetic Induction?
generating current when there is a 90 degrees and no aprochement of any factor
Generating current through the wire in a changing MF
changing MF and changing current
Wire moves up what is the sign ?
+
-
Wire moves down ?
-
+
Electromotive force :
How is current produced by electromagnetic induction?
Volt (EE)
charge flow from high to low potential (EMF)
non of the above are correct
Battery (EE) charge flow from high to low potential (EMF)
EMF IS ________________
Potential difference
potential electric
A force
a vector quantity
Induced EMF property
When wire moves perpen to MF
When velocity is perpen to MF
when sin is parallel
Separation of charges that works as a process of an induced EMF produces an
MF field
electric field
Magnitude of Induced EMF
EMF=B.Q.V SIN
EMF=B.I.L SIN
EMF=B.L.V SIN
I/EMF
THE UNIT GIVEN BY EMF IS ?
VOLT
V
OHMS
CURRENT
I
When wire is parallel to MF
sin =0
sin=90
is there an EMF when it's only at a horizontal position?
YES
NO
Magnitude of current is
I=EMF/R
I=EMF/L
I=EMF/T
Direction of current is the same as the direction of the
MF
FORCE
CURRENT
What do microphones use to work?
MF
EF
EMF
GENERATOR
microphones work
Reverse
parallel
Start to generate a sort of energy
What conversion factors do microphones typically have in commmon?
Sound to electrical signals (energy )
mechanical
electrical to mechanical
Microphones work too by _________ __________
electromagnetic force
electromotive force
electromagnetic induction
Process of how microphones start working?
1. sound vibrates sounds
2.attached to coil that moves
3.motion of coil MF induces emf
1. sound vibrates diaphragm
2. attached to a coil that moves
3. motion of coil MF induces emf
4. current is finally generated
All of the above are reasons of microphones working
The induced EMF and current vary as the frequency of the sound varies
True
False
Can a potential difference be amplified ?
Yes
by electronic devices
no
it's a different componenet
current generated is never prop to sound wave
True
False
Application of induced EMF is ?
Transducers
dynmic
micro
Does microphones rely on electromagnetic induction ?
Yes, and it's also the principle of governing the operation of electric generators.
no and it's neither an example of generator
Electromagnetic induction is the _________
principle of energy transition
principle of controlling operation of electric generators
principle of controlling operation of electric motor
Define electric generator ?
converts mechanical to Kinetik
converts elctricical energy to motor
convert kinetic to electrical
converts mechanical to electrical
Components of electric generator
wire loops
iron core
flips
brushes
what does the image illustrates
generator
motor
What does this image illustrates ?
generator
motor
components of electric generator ?
wire loops
iron core
brushes
comutator
armature
What makes the aramature in a generator ?
iron and wire
iron and fild
cores of bruehs
what happens to the current while the wire loop is rotating in circiut in a MF
induced emf
induced current
direction and strength of induced current _______________
changes every second per cycle
rotation and ellipses
changes as loop rotates
What is the direction of the current when the loop is horizontal to field ?
sin 90
sin 0
both answers are correct depend on how ia the angle
current from a generator
like a brush
like an armature in motor
like a split rings in a motor
armature in generator
moves
rotates
increasing no of loops increases
increases the time
increases the wave
increases the wire length
increases the toatal induced emf
larger emf
strong area
strong b
strong current
induced EMF produces current in a loop when its
a open circiut
closed circiut
what things happen as loop rotates in a generator ?
strength and direction of current changes
strength
direction of the induced current
only component that is perpen
wire's velocity pepen to force
wire's velocity pepen to MF
wire's velocity pepen to area
wire's velocity pepen to line
current is strongest when
perpen
paralel
ever decreasing angle is mentioned when
parralle 3 lines
horizaontal position
vertical posistion
paralel 8 lines
ever decreasing angle cuts mf lines
T
F
What happens to the current at ever decreasing angle when it's vertical
current increases
current amplifies
current reduces
all of the above
current is ___ degrees when at vertical position
90
70
0
45
why is it 0 when its at a vertical position
beacsue it's high enogh
because it's perpendicular
non of the above
because its parallel
as loop rotates current reverse
0 to max or min
o
o to max max
0 to max and back to the same thing each half turn 180
EMF
current reversal
voltage low speed
any form of energy to electrical energy
potentiometer measures
Volts
EMF
ELECTRCITY
electromagnetic induction is the same as ...........
controlling operation
controlling magnets
controlling operations of electric generators
controlling operations of electric motors
Armature in electric generator also called
hand
right hand rule
left hand rule
rotor
The current in a generator is like the armature in a motor
True
False
stronger EMF
stronger the loops
stronger the effect of resistance
stronger current
all of the above
what reveres each time when a loop turns from 0 to 180
voltage
emf
current
Max current is not generated when rotating loop is horizontal to MF lines
True
False
Is current produced in a longer or shorter segment
shorter
longer
There are current produced in the longer segment
true
false
are all parts of loop contribute to induce an emf
yes
no
What is a source of electric generators ?
Wind solars
Wind turbines
solar power
magnetism
total emf produces current at the same time at which process?
wind turbines loops in an armature
wind turbines loops in brushes
The turbines are attached____________ to an armature.
perpendicular
electorally
mechanically
What happens when generator is connected to circuit?
voltage produced by emf
current produced by emf
are generator and motor identical ?
yes
no
Are generators and motors reversed
yes
no
AC current generators uses ____to connect wires to circuit
shaft
commutator
electricity
slip ring device
current alternates from ___ to ___ .
+,+
+,-
Why does the AC current generator uses a slip ring device ?
To insure that current in more than one direction and to reverse
To see that current in more than one direction and to stay the same
to see that current in more than one direction
AC generator is identical to motor except they have _______ and don't have _______ .
commutator, it connects to circuit using slip ring
it connects to circuit using slip ring, commutator
all have the same emf process
Motor has the component ...........
commutator
insulator
The power is always --------- delivered by generator
negative
neutral
positive
current alternates at fixed rates and then reverses
True
False
United States uses
60Hz
120Hz
60 hz frequency means
time
velocity and acceleration of electron
60 times per sec or rotation
Power is the product of
time
frequency
current
PD
Average power is half the max power
t
f
Effective PD refers to the term
RMS
BMS
USA HAS A
120 volts
240 volts outlets
who competed against Thomas Edison by providing AC current instead of DC
nikola tesla
faraday
lenz law as you pull movement of wire induces
EMF so that produces current
CURRENT so that produces current
The moving charges experiences force
True
False
chrges exerts force on wire that oposis motion of wire makes it hard for you to pull
f and v
inverse in dorection
together at same movement
opposing motion is when
the induced field is in the direction that opposes change in field
force is inverse to velocity movement of wire
current can produce MF
oposing change is
inducing EMF
MF can produce current by electromagnetic induction
Inducing current
the induced field is in the direction that opposes change in field
Lenz law states
current produce MF field
MF field produces current
Mf produced by induced current is in the direction that is opposite to change in original fieled
Who's investigation was lenz law
rapping coil of wire
electricity and generators
opposite motion
wire pulled through MF generates an EMF
current produced by induced emf ,mustn't ' me in the same direction
yes
no
to produce mf that opposes the increase in the field....
What condition would you apply
currrent is the direction of b
current and v are pepen
mflux is associated with strength of mf
current produced by induced emf must be in same direction
when you turn an armature
there is a induced emf
induced emf generates no current
