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FCC EXTRA Exam Question Pool. Subelement 4BE.
Electrical Principles. 6 Questions.
---------------------------------------------------
4BE 1.1 B
What is the photoconductive effect?
A. The conversion of photon energy to electromotive energy
B. The increased conductivity of an illuminated semiconductor
junction
C. The conversion of electromotive energy to photon energy
D. The decreased conductivity of an illuminated semiconductor
junction
4BE 1.2 A
What happens to photoconductive material when light shines
on it?
A. The conductivity of the material increases
B. The conductivity of the material decreases
C. The conductivity of the material stays the same
D. The conductivity of the material becomes temperature
dependent
4BE 1.3 D
What happens to the resistance of a photoconductive material
when light shines on it?
A. It increases
B. It becomes temperature dependent
C. It stays the same
D. It decreases
4BE 1.4 C
What happens to the conductivity of a semiconductor junction
when it is illuminated?
A. It stays the same
B. It becomes temperature dependent
C. It increases
D. It decreases
4BE 1.5 D
What is an optocoupler?
A. A resistor and a capacitor
B. A frequency modulated helium-neon laser
C. An amplitude modulated helium-neon laser
D. An LED and a phototransistor
4BE 1.6 A
What is an optoisolator?
A. An LED and a phototransistor
B. A P-N junction that develops an excess positive charge
when exposed to light
C. An LED and a capacitor
D. An LED and a solar cell
4BE 1.7 B
What is an optical shaft encoder?
A. An array of optocouplers chopped by a stationary wheel
B. An array of optocouplers whose light transmission path
is controlled by a rotating wheel
C. An array of optocouplers whose propagation velocity is
controlled by a stationary wheel
D. An array of optocouplers whose propagation velocity is
controlled by a rotating wheel
4BE 1.8 D
What does the photoconductive effect in crystalline solids
produce a noticeable change in?
A. The capacitance of the solid
B. The inductance of the solid
C. The specific gravity of the solid
D. The resistance of the solid
4BE 2A1 D
What is the meaning of the term time constant of an RC circuit?
A. The time required to charge the capacitor in the circuit to
36.8% of the supply voltage
B. The time required to charge the capacitor in the circuit to
36.8% of the supply current
C. The time required to charge the capacitor in the circuit to
63.2% of the supply current
D. The time required to charge the capacitor in the circuit to
63.2% of the supply voltage
4BE 2A2 C
What is the meaning of the term time constant of an RL circuit?
A. The time required for the current in the circuit to build
up to 36.8% of the maximum value
B. The time required for the voltage in the circuit to build
up to 63.2% of the maximum value
C. The time required for the current in the circuit to build
up to 63.2% of the maximum value
D. The time required for the voltage in the circuit to build
up to 36.8% of the maximum value
4BE 2A3 B
What is the term for the time required for the capacitor in
an RC circuit to be charged to 63.2% of the maximum value?
A. An exponential rate of one
B. One time constant
C. One exponential period
D. A time factor of one
4BE 2A4 A
What is the term for the time required for the current in
an RL circuit to build up to 63.2% of the maximum value?
A. One time constant
B. An exponential period of one
C. A time factor of one
D. One exponential rate
4BE 2A5 D
What is the term for the time it takes for a charged capacitor
in an RC circuit to discharge to 36.8% of its initial value of
stored charge?
A. One discharge period
B. An exponential discharge rate of one
C. A discharge factor of one
D. One time constant
4BE 2A6 D
What is meant by back EMF?
A. A current equal to the applied EMF
B. An opposing EMF equal to R times C (RC) percent of
the applied EMF
C. A current that opposes the applied EMF
D. A voltage that opposes the applied EMF
4BE 2B1 C
After two time constants, the capacitor in an RC circuit is
charged to what percentage of the supply voltage?
A. 36.8%
B. 63.2%
C. 86.5%
D. 95%
4BE 2B2 D
After two time constants, the capacitor in an RC circuit is
discharged to what percentage of the starting voltage?
A. 86.5%
B. 63.2%
C. 36.8%
D. 13.5%
4BE 2B3 C
What is the time constant of a circuit having a 100-microfarad
capacitor in series with a 470-kilohm resistor?
A. 4700 seconds
B. 470 seconds
C. 47 seconds
D. 0.47 seconds
4BE 2B4 A
What is the time constant of a circuit having a 220-microfarad
capacitor in parallel with a 1-megohm resistor?
A. 220 seconds
B. 22 seconds
C. 2.2 seconds
D. 0.22 seconds
4BE 2B5 B
What is the time constant of a circuit having two 100-microfarad
capacitors and two 470-kilohm resistors all in series?
A. 470 seconds
B. 47 seconds
C. 4.7 seconds
D. 0.47 seconds
4BE 2B6 B
What is the time constant of a circuit having two 100-microfarad
capacitors and two 470-kilohm resistors all in parallel?
A. 470 seconds
B. 47 seconds
C. 4.7 seconds
D. 0.47 seconds
4BE 2B7 C
What is the time constant of a circuit having two 220-microfarad
capacitors and two 1-megohm resistors all in series?
A. 55 seconds
B. 110 seconds
C. 220 seconds
D. 440 seconds
4BE 2B8 C
What is the time constant of a circuit having two 220-microfarad
capacitors and two 1-megohm resistors all in parallel?
A. 22 seconds
B. 44 seconds
C. 220 seconds
D. 440 seconds
4BE 2B9 B
What is the time constant of a circuit having one 100-microfarad
capacitor, one 220 microfarad capacitor, one 470-kilohm resistor
and one 1-megohm resistor all in series?
A. 68.8 seconds
B. 101.1 seconds
C. 220.0 seconds
D. 470.0 seconds
4BE 2B10 D
What is the time constant of a circuit having a 470-microfarad
capacitor and a 1-megohm resistor in parallel?
A. 0.47 seconds
B. 47 seconds
C. 220 seconds
D. 470 seconds
4BE 2B11 A
What is the time constant of a circuit having a 470-microfarad
capacitor in series with a 470-kilohm resistor?
A. 221 seconds
B. 221000 seconds
C. 470 seconds
D. 470000 seconds
4BE 2B12 A
What is the time constant of a circuit having a 220-microfarad
capacitor in series with a 470-kilohm resistor?
A. 103 seconds
B. 220 seconds
C. 470 seconds
D. 470000 seconds
4BE 2B13 B
How long does it take for an initial charge of 20 V dc to
decrease to 7.36 V dc in a 0.01-microfarad capacitor when
a 2-megohm resistor is connected across it?
A. 12.64 seconds
B. 0.02 seconds
C. 1 second
D. 7.98 seconds
4BE 2B14 A
How long does it take for an initial charge of 20 V dc to
decrease to 2.71 V dc in a 0.01-microfarad capacitor when
a 2-megohm resistor is connected across it?
A. 0.04 seconds
B. 0.02 seconds
C. 7.36 seconds
D. 12.64 seconds
4BE 2B15 D
How long does it take for an initial charge of 20 V dc to
decrease to 1 V dc in a 0.01-microfarad capacitor when a
2-megohm resistor is connected across it?
A. 0.01 seconds
B. 0.02 seconds
C. 0.04 seconds
D. 0.06 seconds
4BE 2B16 A
How long does it take for an initial charge of 20 V dc to
decrease to 0.37 V dc in a 0.01-microfarad capacitor when
a 2-megohm resistor is connected across it?
A. 0.08 seconds
B. 0.6 seconds
C. 0.4 seconds
D. 0.2 seconds
4BE 2B17 C
How long does it take for an initial charge of 20 V dc to
decrease to 0.13 V dc in a 0.01-microfarad capacitor when
a 2-megohm resistor is connected across it?
A. 0.06 seconds
B. 0.08 seconds
C. 0.1 seconds
D. 1.2 seconds
4BE 2B18 D
How long does it take for an initial charge of 800 V dc to
decrease to 294 V dc in a 450-microfarad capacitor when a
1-megohm resistor is connected across it?
A. 80 seconds
B. 294 seconds
C. 368 seconds
D. 450 seconds
4BE 2B19 D
How long does it take for an initial charge of 800 V dc to
decrease to 108 V dc in a 450-microfarad capacitor when a
1-megohm resistor is connected across it?
A. 225 seconds
B. 294 seconds
C. 450 seconds
D. 900 seconds
4BE 2B20 A
How long does it take for an initial charge of 800 V dc to
decrease to 39.9 V dc in a 450-microfarad capacitor when a
1-megohm resistor is connected across it?
A. 1350 seconds
B. 900 seconds
C. 450 seconds
D. 225 seconds
4BE 2B21 D
How long does it take for an initial charge of 800 V dc to
decrease to 40.2 V dc in a 450-microfarad capacitor when a
1-megohm resistor is connected across it?
A. Approximately 225 seconds
B. Approximately 450 seconds
C. Approximately 900 seconds
D. Approximately 1350 seconds
4BE 2B22 C
How long does it take for an initial charge of 800 V dc to
decrease to 14.8 V dc in a 450-microfarad capacitor when a
1-megohm resistor is connected across it?
A. Approximately 900 seconds
B. Approximately 1350 seconds
C. Approximately 1804 seconds
D. Approximately 2000 seconds
4BE 3.1 A
What is a Smith Chart?
A. A graph for calculating impedance along transmission lines
B. A graph for calculating great circle bearings
C. A graph for calculating antenna height
D. A graph for calculating radiation patterns
4BE 3.2 B
What type of coordinate system is used in a Smith Chart?
A. Voltage and current circles
B. Resistance and reactance circles
C. Voltage and current lines
D. Resistance and reactance lines
4BE 3.3 C
What type of calculations can be preformed using a
Smith Chart?
A. Beam headings and radiation patterns
B. Satellite azimuth and elevation angles
C. Impedance and SWR values in transmission lines
D. Circuit gain calculations
4BE 3.4 C
What are the two family of circles that make up a
Smith Chart?
A. Resistance and voltage
B. Reactance and voltage
C. Resistance and and reactance
D. Voltage and impedance
4BE 3.5 B
What is the only straight line on a blank Smith Chart?
A. The reactance axis
B. The resistance axis
C. The voltage axis
D. The current axis
4BE 3.6 C
What is the process of normalizing with regard to a
Smith Chart?
A. Reassigning resistance values with regard to the
reactance axis
B. Reassigning reactance values with regard to the
resistance axis
C. Reassigning resistance values with regard to the
prime center
D. Reassigning prime center with regard to the
reactance axis
4BE 3.7 D
What are the curved lines on a Smith Chart?
A. Portions of current circles
B. Portions of voltage circles
C. Portions of resistance circles
D. Portions of reactance circles
4BE 3.8 C
What is the third family of circles, which are added to a
Smith Chart during the process of solving problems?
A. Coaxial length circles
B. Antenna length circles
C. Standing wave ratio circles
D. Radiation pattern circles
4BE 3.9 B
How are the wavelength scales on a Smith Chart calibrated?
A. In portions of transmission line electrical frequency
B. In portions of transmission line electrical wavelength
C. In portions of antenna electrical wavelength
D. In portions of antenna electrical frequency
4BE 4.1 A
What is the impedance of a network comprised of a 0.1-microhenry
inductor in series with a 20-ohm resistor, at 30 MHz? (Specify
your answer in rectangular coordinates.)
A. 20 + j19
B. 20 - j19
C. 19 + j20
D. 19 - j20
4BE 4.2 B
What is the impedance of a network comprised of a 0.1-microhenry
inductor in series with a 30-ohm resistor, at 5 MHz? (Specify
your answer in rectangular coordinates.)
A. 30 - j3
B. 30 + j3
C. 3 + j30
D. 3 - j30
4BE 4.3 A
What is the impedance of a network comprised of a 10-microhenry
inductor in series with a 40-ohm resistor, at 500 MHz? (Specify
your answer in rectangular coordinates.)
A. 40 + j31400
B. 40 - j31400
C. 31400 + j40
D. 31400 - j40
4BE 4.4 D
What is the impedance of a network comprised of a 100-picofarad
capacitor in parallel with a 4000-ohm resistor at 500 kHz?
(Specify your answer in polar coordinates.)
A. 2490 ohms, @ 51.5 degrees
B. 4000 ohms, @ 38.5 degrees
C. 5112 ohms, @ -38.5 degrees
D. 2490 ohms, @ -51.5 degrees
4BE 4.5 A
What is the impedance of a network comprised of a 0.001-microfarad
capacitor in series with a 400-ohm resistor, at 500 kHz? (Specify
your answer in rectangular coordinates.)
A. 400 - j318
B. 318 - j400
C. 400 + j318
D. 318 + j400
4BE 5.1 B
What is the impedance of a network comprised of a 100-ohm
reactance inductor in series with a 100-ohm resistor?
(Specify your answer in polar coordinates.)
A. 121 ohms, @ 35 degrees
B. 141 ohms, @ 45 degrees
C. 161 ohms, @ 55 degrees
D. 181 ohms, @ 65 degrees
4BE 5.2 C
What is the impedance of a network comprised of a 100-ohm
reactance inductor, a 100-ohm reactance capacitor, and a
100-ohm resistor, all connected in series? (Specify your
answer in polar coordinates.)
A. 100 ohms, @ 90 degrees
B. 10 ohms, @ 0 degrees
C. 100 ohms, @ 0 degrees
D. 10 ohms, @ 100 degrees
4BE 5.3 D
What is the impedance of a network comprised of a 400-ohm
reactance capacitor in series with a 300-ohm resistor?
(Specify your answer in polar coordinates.)
A. 240 ohms, @ 36.9 degrees
B. 240 ohms, @ -36.9 degrees
C. 500 ohms, @ 53.1 degrees
D. 500 ohms, @ -53.1 degrees
4BE 5.4 A
What is the impedance of a network comprised of a 300-ohm
reactance capacitor, a 600-ohm reactance inductor, and a
400-ohm resistor, all connected in series? (Specify your
answer in polar coordinates.)
A. 500 ohms, @ 37 degrees
B. 400 ohms, @ 27 degrees
C. 300 ohms, @ 17 degrees
D. 200 ohms, @ 10 degrees
4BE 5.5 A
What is the impedance of a network comprised of a 400-ohm
reactance inductor in parallel with a 300-ohm resistor?
(Specify your answer in polar coordinates.)
A. 240 ohms, @ 36.9 degrees
B. 240 ohms, @ -36.9 degrees
C. 500 ohms, @ 53.1 degrees
D. 500 ohms, @ -53.1 degrees
4BE 6A1 B
What is the impedance of a network comprised of a 1.0-millihenry
inductor in series with a 200-ohm resistor, at 30 kHz? (Specify
your answer in rectangular coordinates.)
A. 200 - j188
B. 200 + j188
C. 188 + j200
D. 188 - j200
4BE 6A2 C
What is the impedance of a network comprised of a 10-millihenry
inductor in series with a 600-ohm resistor, at 10 kHz? (Specify
your answer in rectangular coordinates.)
A. 628 + j600
B. 628 - j600
C. 600 + j628
D. 600 - j628
4BE 6A3 D
What is the impedance of a network comprised of a 0.01-microfarad
capacitor in parallel with a 300-ohm resistor, at 50 kHz? (Specify
your answer in rectangular coordinates.)
A. 150 - j159
B. 150 + j159
C. 159 + j150
D. 159 - j150
4BE 6A4 B
What is the impedance of a network comprised of a 0.1-microfarad
capacitor in series with a 40-ohm resistor, at 50 kHz? (Specify
your answer in rectangular coordinates.)
A. 40 + j32
B. 40 - j32
C. 32 - j40
D. 32 + j40
4BE 6A5 C
What is the impedance of a network comprised of a 1.0-microfarad
capacitor in parallel with a 30-ohm resistor, at 5 MHz? (Specify
your answer in rectangular coordinates.)
A. 0.000034 + j.032
B. 0.032 + j.000034
C. 0.000034 - j.032
D. 0.032 - j.000034
4BE 6B1 B
What is the impedance of a network comprised of a 100-ohm
reactance capacitor in series with a 100-ohm resistor?
(Specify your answer in polar coordinates.)
A. 121 ohms, @ -25 degrees
B. 141 ohms, @ -45 degrees
C. 161 ohms, @ -65 degrees
D. 191 ohms, @ -85 degrees
4BE 6B2 C
What is the impedance of a network comprised of a 100-ohm
reactance capacitor in parallel with a 100-ohm resistor?
(Specify your answer in polar coordinates.)
A. 31 ohms, @ -15 degrees
B. 51 ohms, @ -25 degrees
C. 71 ohms, @ -45 degrees
D. 91 ohms, @ -65 degrees
4BE 6B3 B
What is the impedance of a network comprised of a 300-ohm
reactance inductor in series with a 400-ohm resistor?
(Specify your answer in polar coordinates.)
A. 400 ohms, @ 27 degrees
B. 500 ohms, @ 37 degrees
C. 600 ohms, @ 47 degrees
D. 700 ohms, @ 57 degrees
4BE 6B4 A
What is the impedance of a network comprised of a 100-ohm
reactance inductor in parallel with a 100-ohm resistor?
(Specify your answer in polar coordinates.)
A. 71 ohms, @ 45 degrees
B. 81 ohms, @ 55 degrees
C. 91 ohms, @ 65 degrees
D. 100 ohms, @ 75 degrees
4BE 6B5 D
What is the impedance of a network comprised of a 300-ohm
reactance capacitor in series with a 400-ohm resistor?
(Specify your answer in polar coordinates.)
A. 200 ohms, @ -10 degrees
B. 300 ohms, @ -17 degrees
C. 400 ohms, @ -27 degrees
D. 500 ohms, @ -37 degrees
--------------------------------------------------
End of Subelement 4BE.