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- Multiple ChoicePlease save your changes before editing any questions.
Primary winding of a transformer is determined by _________.
which winding has more turns
which winding is nearer to the load
which winding is connected to the source
which side has the highest voltage
- Multiple ChoicePlease save your changes before editing any questions.
What type of transformer is used to increase the voltage from power stations?
Step-down transformer
Step-up transformer
- Multiple ChoicePlease save your changes before editing any questions.
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
- Multiple ChoicePlease save your changes before editing any questions.
Which of the following does not change in a transformer?
Voltage
Current
Power
Frequency
- Multiple ChoicePlease save your changes before editing any questions.
This picture is an example of a ________________.
Motor
Generator
Step-up transformer
Step-down transformer
- Multiple ChoicePlease save your changes before editing any questions.
Ratio of voltages is equal to ratio of _______________________.
number of iron sheets in core
resistance
number of turns in coil
number of electromagnetic
- Multiple ChoicePlease save your changes before editing any questions.
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
- Multiple ChoicePlease save your changes before editing any questions.
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
- Multiple ChoicePlease save your changes before editing any questions.
A step up transformer has its primary winding to secondary winding ratio
Greater than 1
Equal to 1
Less than 1
Unknown
- Multiple ChoicePlease save your changes before editing any questions.
The electrical energy is transferred through the ... in a transformer.
electric field
motor
air space
magnetic field
- Multiple ChoicePlease save your changes before editing any questions.
A step up transformer _____________.
decreases voltage
increases current
increases power
increases frequency
- Multiple ChoicePlease save your changes before editing any questions.
Transformers are able to transform both AC and DC Voltages in a Circuit
True
False
- Multiple ChoicePlease save your changes before editing any questions.
The input voltage to a transformer is usually ____ voltage.
AC
DC
both AC & DC
- Multiple ChoicePlease save your changes before editing any questions.
Moving a permanent magnet through a coil of wire will
demagnetize the magnet
the wire will become an electromagnet
the magnet will become electrified
a current will be generated in the wire
- Multiple ChoicePlease save your changes before editing any questions.
What type of current is produced in a battery
induced
magnetic
alternating
direct