Electrical Mechanic/Test Technician Questions and Answers
1. Voltage: an electromotive force or potential difference expressed in volts. Poten-
tial to do work.
2. Direct Current (DC): Electric current that flows in only one direction
3. Alternating Current (AC): A flow of electric charge that regularly reverses its
direction. Bidirectional.
4. Wattage: the electrical power consumed by a device.
5. Coulomb: the SI unit of electric charge, equal to the quantity of electricity con-
veyed in one second by a current of one ampere.
6. 1 amp = 1 coulomb/sec: 1 amp = 6.25 x 10 (18)
7. Ohm: unit of electrical resistance
8. Ampere (amp): Unit that measures the strength of an electric current.
9. Ammeter: a device used to measure current in amperes.
10. Voltmeter: a device used to measure electrical potential or voltage.
11. Wattmeter: Measures electric power in watts
12. Megger: An instrument used for checking the insulation resistance on motors,
feeders, bus bar systems, grounds, and branch circuit wiring. Read in millions of
ohms.
13. Oscilloscope: a device used to display the shape of an electrical wave.
14. Multimeter: A measuring instrument for current, voltage, and resistance.
15. Frequency meter: Used to measure the frequency of an AC signal.
16. micrometer: A gauge which measures small distances or thicknesses.
17. vernier caliper: instrument used for measuring precise linear dimensions
18. Wire gauge: A standard measure of the diameter or thickness of a strand of wire
19. Ohmeter: a device used to measure resistance
20. Architect's Scale: A specialized ruler used in making or measuring reduced
scale drawings. It is marked with a range of calibrated ratios used for laying out
distances, with scales indicating feet, inches, and fractions of inches. Used on
drawings other than site plans.
21. Planimeter: Engineering tool designed to measure distance as its pointer is
traced around a pattern.
22. Of the following electrical devices, the one that is NOT normally used in
direct current electrical circuits is a ....
A. Circuit breaker
B. Double-pole switch
C. Transformer
D. Inverter: C. Transformer
Transformers do not use direct current (DC). Transformers work on alternating cur-
rent (AC), which is electrical current that flows in a single direction. A transformer's
principle is based on electromagnetic induction, which requires a voltage source that
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, Electrical Mechanic/Test Technician Questions and Answers
changes with time. A DC supply is unidirectional, so the transformer cannot work. If
the input terminals of a transformer are connected to a DC voltage, the transformer
usually burns.
23. Of the following motors, the one that does NOT have brushes is the
motor.
A. DC shunt
B. DC series
C. Squirrel cage induction
D. Compound: C. Squirrel cage induction. Cheap and easy to install - squirrel
cage induction motors do not contain brushes, slip rings, commutators, permanent
magnets, position sensors, or other components that increase their overall cost.
Their simple construction ensures they are generally easy to install and maintain.
24. Of the following materials, the one that is COMMONLY used as an electric
heating element in an electric heater is...
A. Zinc
B. Brass
C. Terne plate
D. Nichrome: D. Nichrome. Most heating elements use Nichrome 80/20, which is
80% nickel and 20% chromium. Nichrome is ideal because it has high resistance
and forms a chromium oxide layer when heated for the first time.
25. A bolt is specified as 1/4-28 means the...: Bolt is 1/4 inch in diameter and has
28 threads per inch
26. Name 3 basic components of the atom:: Proton, neutron, electron
27. Two opposing forces hold the electron in place. They are force
and attraction.: Centrifugal force & electrical attraction
28. electromotive force (emf): Electrons can be moved from one atom to another
by applying some form of or pressure.
29. Amperage (amps): The measurement of the amount of electricity flowing past
a given point in a conductor per second (i.e., current).
30. Voltage: an electromotive force or potential difference expressed in volts.
31. Resistance to the flow of electrons is measured in .: Ohms (©)
32. The difference in voltage between two points is called potential.-
: Electrical
33. Alternating current will produce a wave.: Sine
34. Hertz (Hz): Unit of measurement for frequency (cycles per second). Only for AC.
35. To measure the insulation of a rubber-covered electrical cable, the instru-
ment to use should be ..... Ohmmeter
36. Load: The work required to be done. Observed as an amperage draw in an
electric circuit.
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1. Voltage: an electromotive force or potential difference expressed in volts. Poten-
tial to do work.
2. Direct Current (DC): Electric current that flows in only one direction
3. Alternating Current (AC): A flow of electric charge that regularly reverses its
direction. Bidirectional.
4. Wattage: the electrical power consumed by a device.
5. Coulomb: the SI unit of electric charge, equal to the quantity of electricity con-
veyed in one second by a current of one ampere.
6. 1 amp = 1 coulomb/sec: 1 amp = 6.25 x 10 (18)
7. Ohm: unit of electrical resistance
8. Ampere (amp): Unit that measures the strength of an electric current.
9. Ammeter: a device used to measure current in amperes.
10. Voltmeter: a device used to measure electrical potential or voltage.
11. Wattmeter: Measures electric power in watts
12. Megger: An instrument used for checking the insulation resistance on motors,
feeders, bus bar systems, grounds, and branch circuit wiring. Read in millions of
ohms.
13. Oscilloscope: a device used to display the shape of an electrical wave.
14. Multimeter: A measuring instrument for current, voltage, and resistance.
15. Frequency meter: Used to measure the frequency of an AC signal.
16. micrometer: A gauge which measures small distances or thicknesses.
17. vernier caliper: instrument used for measuring precise linear dimensions
18. Wire gauge: A standard measure of the diameter or thickness of a strand of wire
19. Ohmeter: a device used to measure resistance
20. Architect's Scale: A specialized ruler used in making or measuring reduced
scale drawings. It is marked with a range of calibrated ratios used for laying out
distances, with scales indicating feet, inches, and fractions of inches. Used on
drawings other than site plans.
21. Planimeter: Engineering tool designed to measure distance as its pointer is
traced around a pattern.
22. Of the following electrical devices, the one that is NOT normally used in
direct current electrical circuits is a ....
A. Circuit breaker
B. Double-pole switch
C. Transformer
D. Inverter: C. Transformer
Transformers do not use direct current (DC). Transformers work on alternating cur-
rent (AC), which is electrical current that flows in a single direction. A transformer's
principle is based on electromagnetic induction, which requires a voltage source that
1/8
, Electrical Mechanic/Test Technician Questions and Answers
changes with time. A DC supply is unidirectional, so the transformer cannot work. If
the input terminals of a transformer are connected to a DC voltage, the transformer
usually burns.
23. Of the following motors, the one that does NOT have brushes is the
motor.
A. DC shunt
B. DC series
C. Squirrel cage induction
D. Compound: C. Squirrel cage induction. Cheap and easy to install - squirrel
cage induction motors do not contain brushes, slip rings, commutators, permanent
magnets, position sensors, or other components that increase their overall cost.
Their simple construction ensures they are generally easy to install and maintain.
24. Of the following materials, the one that is COMMONLY used as an electric
heating element in an electric heater is...
A. Zinc
B. Brass
C. Terne plate
D. Nichrome: D. Nichrome. Most heating elements use Nichrome 80/20, which is
80% nickel and 20% chromium. Nichrome is ideal because it has high resistance
and forms a chromium oxide layer when heated for the first time.
25. A bolt is specified as 1/4-28 means the...: Bolt is 1/4 inch in diameter and has
28 threads per inch
26. Name 3 basic components of the atom:: Proton, neutron, electron
27. Two opposing forces hold the electron in place. They are force
and attraction.: Centrifugal force & electrical attraction
28. electromotive force (emf): Electrons can be moved from one atom to another
by applying some form of or pressure.
29. Amperage (amps): The measurement of the amount of electricity flowing past
a given point in a conductor per second (i.e., current).
30. Voltage: an electromotive force or potential difference expressed in volts.
31. Resistance to the flow of electrons is measured in .: Ohms (©)
32. The difference in voltage between two points is called potential.-
: Electrical
33. Alternating current will produce a wave.: Sine
34. Hertz (Hz): Unit of measurement for frequency (cycles per second). Only for AC.
35. To measure the insulation of a rubber-covered electrical cable, the instru-
ment to use should be ..... Ohmmeter
36. Load: The work required to be done. Observed as an amperage draw in an
electric circuit.
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