Have an account?
Skip to Content
Build your own quiz
Suggestions for you
28 questions
Show Answers
See Preview
- 1. Multiple Choice
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
- 2. Multiple Choice
What type of transformer is used to increase the voltage from power stations.
Step-down transformer
Step-up transformer
- 3. Multiple Choice
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
- 4. Multiple Choice
Which of the following does not change in a transformer?
Voltage
Current
Power
Frequency
- 5. Multiple Choice
What is the material used for construction of transformer core?
Aluminium
Copper
Silicon steel
Wood
- 6. Multiple Choice
This picture is an example of a ________________.
Motor
Generator
Step-up transformer
Step-down transformer
- 7. Multiple Choice
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
- 8. Multiple Choice
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
- 9. Multiple Choice
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
- 10. Multiple Choice
A step up transformer has its primary winding to secondary winding ratio
Greater than 1
Equal to 1
Less than 1
Unknown
- 11. Multiple Choice
Insulators are put between core lamination ...
to prevent flux leaks to the neighboring steel sheet
to reduce the cross-sectional area of the core
to prevent short circuit in the transformer
to prevent rusting in the lamination
- 12. Multiple Choice
The electrical energy is transferred through the ... in a transformer.
electric field
rotor
air space
magnetic field
- 13. Multiple Choice
The winding wire is coated with varnish so that ...
it can reduce the heat in the transformer
it can reduce the hysteresis loss
it can prevent the wire from rusted
each turn of the winding is insulated from every other turn
- 14. Multiple Choice
Choose the correct statement:
The efficiency of a transformer is the percentage of the ratio of its input power to the output power
The ratio of the input apparent power to the output apparent power is less than 1 for a practical transformer
The ratio of the number of turns in the secondary winding to the number of turn in the primary winding determine the type of the transformer
Copper loss is due to eddy current in the core
- 15. Multiple Choice
A step up transformer _____________.
decreases voltage
decreases current
increases power
increases frequency
- 16. Multiple Choice
Transformer can able to transform both AC and DC Voltages in a Circuit
True
False
- 17. Multiple Choice
The input voltage to a transformer is usually ____ voltage.
AC
DC
both AC & DC
- 18. Multiple Choice
All permanent magnets have two
magnetic charges
magnetic fields
magnetic needles
magnetic poles
- 19. Multiple Choice
Like poles on a permanent magnet will
attract each other
repel each other
always interact
point in the same direction
- 20. Multiple Choice
The magnetic field lines around a bar magnet
are perfectly straight
are only perpendicular to the magnet
spread out from one pole and curve around to the other
cross back and forth over one another
- 21. Multiple Choice
Which poles on the earth change?
the North and South
the magnetic poles
the geographic poles
the telephone poles
- 22. Multiple Choice
Electric currents passing through wires will produce a(n)
solenoid
magnet
magnetic field
insulator
- 23. Multiple Choice
What makes an electromagnet different than a permanent magnet.....select all that apply
it can be turned on and off
it does not need any electricity
its strength can be increased and decreased
its polarity can be reversed
- 24. Multiple Choice
Which way will NOT increase the strength of the magnetic field of an electromagent
increasing the current
using a stronger ferromagnetic core
winding the coils closer together
decreasing the number of loops
- 25. Multiple Choice
What type of materials are needed to create an electromagnet?
battery, light bulb, plastic straw
battery, coil of wire, iron core
generator, iron core, switch
switch, source of electricity, compass
- 26. Multiple Choice
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
- 27. Multiple Choice
What type of current is produced in a battery
induced
magnetic
alternating
direct
- 28. Multiple Choice
What type of device can increase and decrease voltage?
Generators
Transformers
Galvanometers
Electric motors
- Answer choicesTagsAnswer choicesTags