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14 questions
In order for electromagnetic induction to occur, there must be relative............between a magnetic field and a conductor.
race
Motion
field
voltage
The magnetic field produced by an alternating current can be thought of as a ............................... magnetic field.
moving magnetic field
dynamic magetic field
electrodynamic magnetic field
magnetic field
The transformer is a device used to .......... the value of a voltage.
steady
resist
change
anchor
If a transformer reduces voltage, it is called a....................... transformer.
step left
step right
step up
step down
A laminated transformer core reduces the amount of energy that is wasted in the form of........
solidifying
flux
heat
Why transformers work with A.C. current but not D.C.
A.C current produces changing magnetic field.
D.C current produces changing magnetic field.
D.C current is weak
A.C current is powerful
Which of the following does not change in a transformer?
Voltage
Current
Power
Frequency
This picture is an example of a ________________.
Motor
Generator
Step-up transformer
Step-down transformer
Ratio of voltages is equal to ratio of _______________________.
number of iron sheets in core
number of coil
number of turns in coil
number of electromagnetic
A transformer has 100 turns in the primary coil and 25 turns in the secondary coil. When a 120 V is applied to the primary coil, what is the voltage in the secondary coil?
480V
30V
20V
450V
The function of a transformer is to ...
raise and lower the apparent power levels
transfer DC voltage from the primary winding to the secondary winding
increase or decrease A.C voltage or A.C current levels
transform mechanical energy into electrical energy
The magnetic material for the core needs to be made of soft iron where its permeability is high
to reduce eddy current loss
to reduce hysteresis loss
to avoid fringing in the core
to reduce copper loss in the winding
Transformer works on which of the following principle
Lenz’s Law
Ampere's Law
Faraday's Law of Electromagenetic Induction
Fleming's Law
What is the meaning of transformer?
Optimus Prime
A device that transfers electrical energy from one circuit to another
Autobots
Megatron
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