CET SECTION 3 EXAM QUESTIONS
AND ANSWERS ALL CORRECT
How long should a ¹/₄ wavelength vertical antenna be that is designed for operation on
146 MHz? - Answer- 1.6 feet
What is the common impedance of radio communication and television coaxial cable,
respectively? - Answer- 50 and 75 ohms
Which layer of the ionosphere absorbs high frequency radio waves during daylight
hours? - Answer- D Layer
Which style of antenna has a radiation pattern of 180 degrees? - Answer- Dipole
An AC induction motor requires what to operate? - Answer- slip
What happens to the value of a capacitor if the spacing between plates decreases? -
Answer- increases
How many time constants does it take to charge a capacitor to 63% of the applied
voltage? - Answer- 1
A variable capacitors plates can open or close. aas the plates open, capacitance: -
Answer- decreases
An inductor with the same length of wire but whose turns are spaced further apart will
have - Answer- less inductance
In an AC circuit, as the applied voltage frequency changes upward, the inductive
reactance in the circuit will: - Answer- Decrease
In an AC circuit, as the applied voltage frequency changes upward, the capacitive
reactance in the circuit will: - Answer- increase
in a series circuit when the inductive reactance's equal the capacitor reactance's the
circuit ____ impedance - Answer- Minimum
in a Parallel circuit when the inductive reactance's equal the capacitor reactance's the
circuit ____ impedance - Answer- Maximum
, Resonance is when: - Answer- The total inductive reactance's in the circuit equal the
total of all capacitive reactance's
the basic components of an alternator are __________ - Answer- the field, the
armature, the slip rings and brushes
three phase power consists of three distinct sine waves each lagging the phase before it
by ___________ when viewed on an o-scope - Answer- 120 degrees
AC motor speed depends on the ___________ of the supplied voltage - Answer- The
frequency of the voltage applied to it
the most common type of multiphase AC motors use __________ - Answer- three-
phase power
_______ cells are prone to battery memory - Answer- NiCad
A conducting loop in motion through magnetic lines of flux has current induced to it. the
physical law that explains this is what? - Answer- Lenz 's Law
An AC generator is also known as a/an _____________ - Answer- alternator
three phase power is obtained from an AC generator by wiring the armature windings in
a _______ or ________ configuration - Answer- delta, wye
what element of a DC generator distinguishes it from an AC generator - Answer-
commutator
what type of motor will speed dangerously out of control if not physically loaded. -
Answer- series wound DC motor
series wound DC motor - Answer- the frequency of the voltage applied to it
series wound AC motors have strong torque from a dead stop. This makes them ideally
suited for use small appliances. T/F? - Answer- true
What element of a synchronous AC motor provides start up torque for the motor -
Answer- squirrel cage
an inductor in an electrical circuit: - Answer- opposes the flow of AC current
the term for the combination of resistance and reactance that restricts the flow of
alternating current is: - Answer- impedance
AND ANSWERS ALL CORRECT
How long should a ¹/₄ wavelength vertical antenna be that is designed for operation on
146 MHz? - Answer- 1.6 feet
What is the common impedance of radio communication and television coaxial cable,
respectively? - Answer- 50 and 75 ohms
Which layer of the ionosphere absorbs high frequency radio waves during daylight
hours? - Answer- D Layer
Which style of antenna has a radiation pattern of 180 degrees? - Answer- Dipole
An AC induction motor requires what to operate? - Answer- slip
What happens to the value of a capacitor if the spacing between plates decreases? -
Answer- increases
How many time constants does it take to charge a capacitor to 63% of the applied
voltage? - Answer- 1
A variable capacitors plates can open or close. aas the plates open, capacitance: -
Answer- decreases
An inductor with the same length of wire but whose turns are spaced further apart will
have - Answer- less inductance
In an AC circuit, as the applied voltage frequency changes upward, the inductive
reactance in the circuit will: - Answer- Decrease
In an AC circuit, as the applied voltage frequency changes upward, the capacitive
reactance in the circuit will: - Answer- increase
in a series circuit when the inductive reactance's equal the capacitor reactance's the
circuit ____ impedance - Answer- Minimum
in a Parallel circuit when the inductive reactance's equal the capacitor reactance's the
circuit ____ impedance - Answer- Maximum
, Resonance is when: - Answer- The total inductive reactance's in the circuit equal the
total of all capacitive reactance's
the basic components of an alternator are __________ - Answer- the field, the
armature, the slip rings and brushes
three phase power consists of three distinct sine waves each lagging the phase before it
by ___________ when viewed on an o-scope - Answer- 120 degrees
AC motor speed depends on the ___________ of the supplied voltage - Answer- The
frequency of the voltage applied to it
the most common type of multiphase AC motors use __________ - Answer- three-
phase power
_______ cells are prone to battery memory - Answer- NiCad
A conducting loop in motion through magnetic lines of flux has current induced to it. the
physical law that explains this is what? - Answer- Lenz 's Law
An AC generator is also known as a/an _____________ - Answer- alternator
three phase power is obtained from an AC generator by wiring the armature windings in
a _______ or ________ configuration - Answer- delta, wye
what element of a DC generator distinguishes it from an AC generator - Answer-
commutator
what type of motor will speed dangerously out of control if not physically loaded. -
Answer- series wound DC motor
series wound DC motor - Answer- the frequency of the voltage applied to it
series wound AC motors have strong torque from a dead stop. This makes them ideally
suited for use small appliances. T/F? - Answer- true
What element of a synchronous AC motor provides start up torque for the motor -
Answer- squirrel cage
an inductor in an electrical circuit: - Answer- opposes the flow of AC current
the term for the combination of resistance and reactance that restricts the flow of
alternating current is: - Answer- impedance
