NCTI Installer Tech/November Exam
Questions and Answers 100% Pass
Why do only the outer electrons leave their orbit shells? - ✔✔Only outer electrons leave
their orbit shells because electrons farthest from the nucleus are more easily freed from
their orbits due to a weaker electrostatic force.
What is required to have a balanced (or stable) atom? - ✔✔The number of electrons
must equal the number of protons in order to have a balanced atom.
List the capacity of each of the first four orbital shells of an atom. - ✔✔Shell: #1 = 2
electrons; #2 = 8 electrons; #3 = 18 electrons; and #4 = 32 electrons.
What is the maximum electron capacity of a valence shell? - ✔✔A valence shell can hold
a maximum of eight electrons.
Electrons in orbits nearest the nucleus contain _________ energy than those in more
distant orbits. - ✔✔Electrons in orbits nearest the nucleus contain less energy than those
in more distant orbits.
What will happen to a valence electron that has enough energy added to it? - ✔✔A
valence electron that has enough energy added to it will move away from its atom.
What major factor determines which category a particular element belongs? - ✔✔The
number of electrons in the valence shell determines the element category.
COPYRIGHT © 2025 BY BRITTIE DONALD, ALL RIGHTS RESERVED 1
,How many valence electrons are there in a good conductor? - ✔✔A good conductor has
only one or two valence electrons.
List gold, silver, and copper in the order of best conductivity. (List the best conductor
first.) - ✔✔#1 Silver; #2 Copper; #3 Gold
Why do metals that each have only one valence electron differ in their conductivity? -
✔✔Metals that each have one valence electron differ in their conductivity because of the
way their atoms pack together into a solid structure.
Describe the two characteristics of an insulator. - ✔✔The two characteristics of an
insulator are as follows:
1. Its valence shell is almost filled and tends to be fairly stable.
2. It tries to finish filling its valence shell by capturing additional free electrons.
How many valence electrons are in a semiconductor? - ✔✔A semiconductor has four
valence electrons.
Name the two types of electron current flow. - ✔✔Random drift and directed flow are
the two types of electron current flow.
What causes electrons to be knocked loose and travel randomly from one atom to
another? - ✔✔The movement of atoms in materials that are conductors and the
agitation as they collide cause electrons to be knocked loose and travel randomly from
one atom to another.
What can force electrons to all move in the same direction? - ✔✔Applying a negative
charge to one end of the wire and a positive charge to the other can force electrons to all
move in the same direction. The electrons in the wire will travel toward the positive
charge as they are directed by the effects of the unlike charges.
COPYRIGHT © 2025 BY BRITTIE DONALD, ALL RIGHTS RESERVED 2
,What actually produces electric current? - ✔✔The transfer of energy from valence
electron to valence electron, as a result of applied charges, is what actually produces
electric current.
How does the speed of electric current compare to that of electron travel? - ✔✔The
effective speed of electric current (186,000 miles per second) is much faster than the
actual speed of electron travel (a few hundred miles per second).
How many electrons are in one coulomb? - ✔✔A coulomb is equal to 6.28 × 1018
electrons.
What is the basic measurement unit of electron current? - ✔✔The ampere is the basic
measurement unit for electron current.
Define ampere in terms of coulombs. - ✔✔An ampere is equal to 1 coulomb passing a
given point during 1 second.
Name the three terms that are used interchangeably to refer to the force that causes
current flow. - ✔✔Potential difference, electromotive force (emf), and voltageare used
interchangeably to refer to the force that causes current flow.
Define electromotive force (emf). - ✔✔Emf is the electrical force that motivates electrons
to move in a wire.
What does the term potential difference mean? - ✔✔Potential difference is the algebraic
difference between the electrical individual potentials of two points.
What is the potential difference between two negative charges of equal value? - ✔✔The
potential difference between two negative charges of equal value is zero. There is no
potential difference.
What is the unit used to indicate the strength or size of the potential difference? -
✔✔The volt is the unit used to indicate the strength or size of the potential difference.
COPYRIGHT © 2025 BY BRITTIE DONALD, ALL RIGHTS RESERVED 3
, Define a volt in terms of current and resistance. - ✔✔One volt is the amount of force
required to produce a current of 1 ampere through a resistance of 1 Ω.
What are three alternate ways to express 5 µV and 3 mA? - ✔✔5 microvolts, 5/1,000,000
volt or 0.000005 volt, and 3 milliamperes, 3/1,000 ampere or 0.003 A.
What are two alternate ways to express 2 megavolts? - ✔✔2 MV or 2 million volts.
What are two alternate ways to express 4 kilovolts? - ✔✔4 kV or 4,000 volts.
20 milliamperes is the same as ________. (Remember, 1 milliampere = 0.001 ampere.) -
✔✔0.02 amperes
The orbital shell that has a maximum electron capacity of 18 electrons is the
___________ shell. - ✔✔Third
A semiconductor material - ✔✔Has four valence electrons.
The major factor for determining whether a particular element is a conductor, a
semiconductor, or an insulator is - ✔✔The number of electrons in the valence shell.
Elements that are called conductors - ✔✔Have very few valence electrons.
The term voltage normally refers to - ✔✔The measurement of the difference in potential
between two charges.
The ampere - ✔✔Indicates how many coulombs pass a given point during 1 second.
Electric current is actually produced by - ✔✔The transfer of energy from valence
electron to valence electron as a result of applied charges.
What prevents the electrons that orbit an atom's nucleus at high speeds from breaking
away from the nucleus due to centrifugal force? - ✔✔The attraction between the
positive nucleus and the negative electron.
COPYRIGHT © 2025 BY BRITTIE DONALD, ALL RIGHTS RESERVED 4
Questions and Answers 100% Pass
Why do only the outer electrons leave their orbit shells? - ✔✔Only outer electrons leave
their orbit shells because electrons farthest from the nucleus are more easily freed from
their orbits due to a weaker electrostatic force.
What is required to have a balanced (or stable) atom? - ✔✔The number of electrons
must equal the number of protons in order to have a balanced atom.
List the capacity of each of the first four orbital shells of an atom. - ✔✔Shell: #1 = 2
electrons; #2 = 8 electrons; #3 = 18 electrons; and #4 = 32 electrons.
What is the maximum electron capacity of a valence shell? - ✔✔A valence shell can hold
a maximum of eight electrons.
Electrons in orbits nearest the nucleus contain _________ energy than those in more
distant orbits. - ✔✔Electrons in orbits nearest the nucleus contain less energy than those
in more distant orbits.
What will happen to a valence electron that has enough energy added to it? - ✔✔A
valence electron that has enough energy added to it will move away from its atom.
What major factor determines which category a particular element belongs? - ✔✔The
number of electrons in the valence shell determines the element category.
COPYRIGHT © 2025 BY BRITTIE DONALD, ALL RIGHTS RESERVED 1
,How many valence electrons are there in a good conductor? - ✔✔A good conductor has
only one or two valence electrons.
List gold, silver, and copper in the order of best conductivity. (List the best conductor
first.) - ✔✔#1 Silver; #2 Copper; #3 Gold
Why do metals that each have only one valence electron differ in their conductivity? -
✔✔Metals that each have one valence electron differ in their conductivity because of the
way their atoms pack together into a solid structure.
Describe the two characteristics of an insulator. - ✔✔The two characteristics of an
insulator are as follows:
1. Its valence shell is almost filled and tends to be fairly stable.
2. It tries to finish filling its valence shell by capturing additional free electrons.
How many valence electrons are in a semiconductor? - ✔✔A semiconductor has four
valence electrons.
Name the two types of electron current flow. - ✔✔Random drift and directed flow are
the two types of electron current flow.
What causes electrons to be knocked loose and travel randomly from one atom to
another? - ✔✔The movement of atoms in materials that are conductors and the
agitation as they collide cause electrons to be knocked loose and travel randomly from
one atom to another.
What can force electrons to all move in the same direction? - ✔✔Applying a negative
charge to one end of the wire and a positive charge to the other can force electrons to all
move in the same direction. The electrons in the wire will travel toward the positive
charge as they are directed by the effects of the unlike charges.
COPYRIGHT © 2025 BY BRITTIE DONALD, ALL RIGHTS RESERVED 2
,What actually produces electric current? - ✔✔The transfer of energy from valence
electron to valence electron, as a result of applied charges, is what actually produces
electric current.
How does the speed of electric current compare to that of electron travel? - ✔✔The
effective speed of electric current (186,000 miles per second) is much faster than the
actual speed of electron travel (a few hundred miles per second).
How many electrons are in one coulomb? - ✔✔A coulomb is equal to 6.28 × 1018
electrons.
What is the basic measurement unit of electron current? - ✔✔The ampere is the basic
measurement unit for electron current.
Define ampere in terms of coulombs. - ✔✔An ampere is equal to 1 coulomb passing a
given point during 1 second.
Name the three terms that are used interchangeably to refer to the force that causes
current flow. - ✔✔Potential difference, electromotive force (emf), and voltageare used
interchangeably to refer to the force that causes current flow.
Define electromotive force (emf). - ✔✔Emf is the electrical force that motivates electrons
to move in a wire.
What does the term potential difference mean? - ✔✔Potential difference is the algebraic
difference between the electrical individual potentials of two points.
What is the potential difference between two negative charges of equal value? - ✔✔The
potential difference between two negative charges of equal value is zero. There is no
potential difference.
What is the unit used to indicate the strength or size of the potential difference? -
✔✔The volt is the unit used to indicate the strength or size of the potential difference.
COPYRIGHT © 2025 BY BRITTIE DONALD, ALL RIGHTS RESERVED 3
, Define a volt in terms of current and resistance. - ✔✔One volt is the amount of force
required to produce a current of 1 ampere through a resistance of 1 Ω.
What are three alternate ways to express 5 µV and 3 mA? - ✔✔5 microvolts, 5/1,000,000
volt or 0.000005 volt, and 3 milliamperes, 3/1,000 ampere or 0.003 A.
What are two alternate ways to express 2 megavolts? - ✔✔2 MV or 2 million volts.
What are two alternate ways to express 4 kilovolts? - ✔✔4 kV or 4,000 volts.
20 milliamperes is the same as ________. (Remember, 1 milliampere = 0.001 ampere.) -
✔✔0.02 amperes
The orbital shell that has a maximum electron capacity of 18 electrons is the
___________ shell. - ✔✔Third
A semiconductor material - ✔✔Has four valence electrons.
The major factor for determining whether a particular element is a conductor, a
semiconductor, or an insulator is - ✔✔The number of electrons in the valence shell.
Elements that are called conductors - ✔✔Have very few valence electrons.
The term voltage normally refers to - ✔✔The measurement of the difference in potential
between two charges.
The ampere - ✔✔Indicates how many coulombs pass a given point during 1 second.
Electric current is actually produced by - ✔✔The transfer of energy from valence
electron to valence electron as a result of applied charges.
What prevents the electrons that orbit an atom's nucleus at high speeds from breaking
away from the nucleus due to centrifugal force? - ✔✔The attraction between the
positive nucleus and the negative electron.
COPYRIGHT © 2025 BY BRITTIE DONALD, ALL RIGHTS RESERVED 4
