SITOR-ARQ is a common mode of data communications in the maritime service. It is a system based on transmission bursts and acknowledgements. What is the baud, and interval between the burst transmissions:

100 baud, 240 ms interval

For info, see Wavecome site's article on WAVECOM Decoder Online Help 10.2.0 SITOR-ARQ

For data burst calculation, please see CCIR 476-4 / CCIR 625 Mode A (aka SITOR ARQ / AMTOR)

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Weather information is commonly sent by radio in map form by one-way facsimile transmission. Two common parameters which must be set by the receiving station are:

Index of cooperation (IOC), and revolutions per minute (RPM)

For radiofax, in radio waves SSB mode, sends by radio weather map pictures and information. To translate the radio waves into pictures, in terms of the number of lines, characters per line between the sending machine and the receiving printer, the numerical data was transmitted, known as the index of cooperation (IOC) must known.

Since the radio fax machines used drum readers, the revolutions per minute (RPM) had to be know.

For more info, please see Wikipedia's article on Radiofax.

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2182 kHz is the international radiotelephone distress frequency. It is also used for a calling channel. The authorized mode of emission is H3E (single-sideband full carrier). A3E (double-sideband full carrier) is only authorized for equipment:

Solely intended for distress and safety communications

2182 kHz is Medium Frequency (MF) equivalent of VHF Channel 16. Frequencies in this range typically provide longer range communications.

Code of Federal Regulations, Title 47 Chapter I Subchapter D Part 80 Subpart H Radiotelephony

§ 80.369 Distress, urgency, safety, call and reply frequencies.

47 CFR 80.369(a) In the 1605-3500 kHz band, the frequency 2182 kHz is an international radiotelephony distress, urgency and safety frequency for ship stations, public and private coast stations, and survival craft stations.

It is also used for call and reply by ship stations on a primary basis and by public coast stations on a secondary basis.

The carrier frequency 2191 kHz may be used as a supplementary calling frequency in areas of heavy usage of 2182 kHz .

All stations must use J3E emission when operating on 2182 kHz and 2191 kHz, except that:

47 CFR 80.369(a)(1) H3E emission may be used on 2182 kHz for communications with foreign coast and ship stations; or,

47 CFR 80.369(a)(2) A3E emission may be used on 2182 kHz by portable survival craft stations, or transmitters authorized for use prior to January 1, 1972.

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Ship's power is generated as 3-phase and is ungrounded. On a delta-wound transformer with 120 VAC line-to-line secondary, what is the voltmeter reading from line to ground:

Any of the above

• Approx 67 volts for a normal balanced system with no faults

• VAC for a system with that phase faulted to ground

• 120 VAC when another phase is faulted to ground

The 3-phase current has three sine waves. The currents are at different angles, with L1 at +120 degrees, L2 at 0 degrees, and L3 at -120 degrees. This is needed to power large electric motors.

When you measure voltage between L2 and either L1 or L3, you will get 120 VAC (volt alternating current).

If there is a short (fault) or an abnormal sine wave combination, resulting from a sine wave current coming in contact with ground.

When 3 sine waves work symmetrically, in a coordinated sequence, then they are balanced. When not experiencing a short (or ground connection), then volt measurement reflects the difference between volt levels (voltage is an expression of the difference of electron pressure between two connections)

The Delta configuration uses 3 wires for the 3 sine waves, with no 4th wire, which would have been the neutral ground wire.

For info on electric phase power generation and distribution, please see Wikipedia's article on Three-phase electric power

For info on electric short circuit faults, please see Wikipedia's article on Electrical fault

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When passing through areas of static charge, high voltages can accumulate on antennas which are insulated from ground. What protects a connected receiver from damage?

Any combination of the above

• Lightning arresters and suppressors
• Protection diodes on receiver input
• Capacitive coupling and static dissipative circuits

Static charge occurs when there is a difference between negative and positive number of electrons. Electrons flow from negative (toward) to positive (back) connections.

If the flow is interfered with or stopped, then an accumulation of the negative electrons occurs, which is the static electricity (static=> not moving). Thus, electrons can accumulate on antennas, and discharge on the radio receivers.

To prevent sudden electron transfer, like a short spark when you touch something that was rubbed appropriately, items that can absorb the sudden release of electrons protect the radio receiver.

Capacitive coupling is a capacitor that would absorb the release of stored electrons. Diodes control the flow of electrons.

For more info, please see Wikipedia's article on Static Electricity.

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Vertical shipboard antennas for use in the MF band (410-525 kHz) are often fitted with top-hat loading sections. What is the purpose of these structures?

Permits a physically short antenna to appear electrically longer

The top-hat or T-antenna, is a horizontal wire (akin to the Beverage antenna), suspended between to poles, with a third wire connected at the center of the horizontal wire and connected to the transmitter/receiver, kind of like the dipole antenna.

The receiving waves flow from the horizontal wire to the vertical center wire to the receiver. Transmissions flow from the center wire to the both sides of the horizontal wire.

A vertical wire is connected to the center of the horizontal wires and hangs down close to the ground, connected to the transmitter or receiver.

Combined, the two sections form a ‘T’ shape, hence the name. The transmitter power is applied, or the receiver is connected, between the bottom of the vertical wire and a ground connection.

T-antenna is easily installed ships between masts and vertical center line connected to the trans/receiver. (Even Titanic used this configuration and sended out the distress signal.)

To extend the wavelength of a shorter antenna, it should be mounted as high as possible, as mathematically its height is squared for effective receiving or transmitting.

For more info, please see Wikipedia's article on T-Antenna.

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Modern reserve transmitters are solid-state designs and transmit using only A2 modulation. When measuring transmitter center frequency, what precaution must be taken:

Modulation must be reduced to zero to eliminate sidebands

This modulation can be thought of as the Double Sideband Suppressed Carrier Modulation (DSBSC). Thus, data is sent by modulating the carrier frequency itself. The AM radio can easily pick up these continuous wave propagations.

Because all of the transmitted power (volts x amperes=watts), is concentrated on the carrier frequency, without being dispersed on upper or lower sidebands. Thus, it can carry the signal much farther.

For more info, please see Wikipedia's article on Types of radio emissions and Continuous wave

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Voltage may be expressed by what other expression?

All of the above

• Difference of potential
• IF drop
• Electromotive force

Because the difference in the number of electrons between two items, when they are connected there is a waterfall like flow of electrons. The amount of rushing electrons to the low electrons area is called the volt amount.

It can be thought of as the pressure of the flow of electrons due to the difference in potential (amount of electrons).

If you multiply the amount of electrons, or the current (ampers) by the amount of resistance that a medium through which electrons flow (silver, copper, not glass), then you will get the amount of voltage (pressure on the amount of electrons to move).

Voltage as IF drop may refer to the (I) as symbol for current (ampers) and (F) as factor or force. More on Voltage drop on Wikipedia's article Voltage drop

For Voltage info, see Electrical 4 U site article What is Voltage? and Wikipedia's article Voltage

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Amperage may also be known by:

All of the above

• Electron flow
• Electron drift
• Electric current flow

In simplest terms, it is the amount of electrons flowing through the skin of the conduit (gold, silver, iron, copper). Electrons travel on the surface of the conduits. This called the current, and is measured in amperes.

Voltage is what pushes amperes to flow through the conduit which offers some resistance, measured in ohms.

For more info, see Wikipedia's article on Amperes

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Factors which determine the amplitude of the voltage induced in a conductor which is cutting magnetic lines of force:

All of the above

• Flux density

• Velocity that the conductor cuts the magnetic lines of force

• The angle at which the conductor cuts through the magnetic lines of force

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An electrical potential may be generated by:

All of the above

• Varying a magnetic field through a circuit
• Chemical action
• Photoelectric action

The potential refers to the energy that can be concentrated by various methods.

For more info, please see Wikipedia's article on Electric Potential

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Ohm's law is stated as:

All of the above

• E = IR    Voltage = Current x Resistance
• I = E / R    Current = Voltage / Resistance
• R = E / I    Resistance = Voltage / Current

For more info, please see Wikipedia's article on Ohm's law

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The unit of electrical power is:

strong text- Watt

strong text- Joule per second

Electric power is the amount of energy transferred through the conduit, and is measured in watts, which is Joules per second. It can be thought of as the amount of power, which reflects the "work done" per second. The "work done" is also called Joule unit.

For more info, please see Wikipedia's article on Electric power

Also, see article Is one joule per second equivalent to one watt?

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The unit of conductance is:

Mho

Conductance is the opposite of resistance. The resistance is measured in Ohms, but conductance is measured in Mho's. The Mho, is the 1/ohm, that is the Mho is the reciprocal of Ohm.

For more info, please see ElectronicNotes' site article Electrical Conductivity: mho, siemens

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The unit of inductance is:

Henry

The inductance is the magnetic field caused by the flow of current, and this field works like resistance to the current flow. The unit of inductance, Henry, refers to Joseph Henry who discovered inductance.

For more info, see Wikipedia's article Inductance Also, see article on Joseph Henry

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The ratio of current through a conductor to the voltage which produces it is:

Conductance

It measures how well electricity flows through the skin of the substance such as silver, gold, copper, iron, etc.

For more info, see Electrical4U site, article Conductance: What is it? (Definition, Units & Formula)

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The product of the number of turns and the current in amperes used to describe relative magnitude is:

Ampere turns

When you run electric current through wires that were wound in a circular pattern, you get a magnetic field that is strong. In fact, whenever you run current, there is a magnetic field. In the coil, the field is strong because the field goes through the center of the coil.

The more turns in the coil, then there is more magnetic field created.

For more info, see Wikipedia's article Electromagnetic coil
and Tesla Scientific site's Ampere-Turn Calculator

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The property of a conductor or coil which causes a voltage to be developed across its terminals when the number of magnetic lines of force in the circuit or coil is changed is:

Inductance

The inductance is the magnetic field caused by the flow of current, and this field works like resistance to the current flow. The unit of inductance, Henry, refers to Joseph Henry who discovered inductance.

For more info, see Wikipedia's article [Inductance][1] Also, see article on [Joseph Henry][2]

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The charge of electricity which passes a given point in one second when a current of one ampere is flowing is:

Coulomb

Coulomb has been adopted as the internationally recognized amount of electric charge, which is the amount of amperes (electrons flowing) per second.

For more info, see Wikipedia's article on Coulomb

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C = capacity in farads.
Q = the measure of the quantity of charge of electricity in Coulombs.
E = the applied voltage.
So Q = CE:

Determines the quantity of charge in a capacitor

Coulomb or amount of amperes =
Farads (ability to store electricity) x
Voltage (the amount of difference between two unit's charges or the amount of force pushing of electrons from a unit to another)

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Resistance is:

All of the above

• The quantity which determines power loss or dissipation
• The factor of proportionality between voltage and current
• Measured in ohms

The amount of resistance (in Ohms) that the electrons (in Amperes) experience when are pushed through a conductor by Voltage pressure.

For more info, see Fluke's site article on What is resistance?
and Wikipedia's article on Electrical resistance and conductance

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The unit of AC impedance in a circuit is:

Ohm

• The quantity which determines power loss or dissipation
• The factor of proportionality between voltage and current
• Measured in ohms

The amount of resistance (in Ohms) that the electrons (in Amperes) experience when are pushed through a conductor by Voltage pressure.

In AC current, the resistance changes the shape of the electrical wave (sinusoidal waveform)

For more details, see Electronic Tutorials' site article AC Resistance and Impedance

For more info, see Fluke's site article on What is resistance?
and Wikipedia's article on Electrical resistance and conductance

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The unit of capacitance is:

A & B

• Farad
• Microfarad

Ability to store electrons (amperes) in a medium is measured by Farad units. Capacitors are used to store electric charges. Since a unit of Farad has a substantial charge, for smaller charges a microfarad unit is used to measure.

For more info, see Fluke's article on What is capacitance?
and Wikipedia's article on Capacitance

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Decibel is:

Both A & B

• The unit used to express the ratio between two sound power levels

• The unit used to express the ratio between two electrical power levels

Basically, the amount of push on air, air pressure, is measured in decibels. Decibels increase in logarithmic units, not arithmetical units.

For more info, see Physclips' article on dB: What is a decibel?
and Wikipedia's article on Decibel

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What factors determine the charge stored in a capacitor?

Both A & B

• Capacitance of the capacitor
• The applied voltage

Capacitors store electrical charges when pressure is placed on electrons to move (applied voltage) to a capacitor.

The ability to store electrons (amperes) in a medium is measured by Farad units. Capacitors are used to store electric charges. Since a unit of Farad has a substantial charge, for smaller charges a microfarad unit is used to measure.

For more info, see Fluke's article on What is capacitance?
and Wikipedia's article on Capacitance

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Ohm's law for AC circuits when
I = amperes,
E = volts,
Z = impedance in volts is:

(D). All of the above

• I = E/Z   Amperes = volts / ohms
• E = IZ   Volts = amperes x ohms
• Z= E/I   Ohms = volts / current

It appears that the Z=Z/I in answer C maybe simply misprint

I = E / R  Current =   Voltage / Resistance
E = IR   Voltage =  Current x Resistance
R = E / I  Resistance = Voltage / Current

For more info, please see Wikipedia's article on Ohm's law

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The formula for determining the power in a DC circuit when the voltage and resistance are known is:

(A). P = ( E squared) R

Power is measured in watts, or in units of Joule per second.

Watts = Amperes x Voltage or
Watts = (Amperes)2 x Resistance or
Watts = (Voltage)2 / Resistance

For more info, see Electrical Technology site's article on Power Formulas in DC and AC Single-Phase & Three-Phase Circuits

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The formula for finding power in a DC circuit when current and resistance are known:

(B). P = ( I Squared) R

Power is measured in watts, or in units of Joule per second.

Watts = Amperes x Voltage or
Watts = (Amperes)2 x Resistance or
Watts = (Voltage)2 / Resistance

For more info, see Electrical Technology site's article on Power Formulas in DC and AC Single-Phase & Three-Phase Circuits

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The formula for finding power in a DC circuit when current and voltage are known:

(A). P = EI

Power is measured in watts, or in units of Joule per second.

Watts = Amperes x Voltage or
Watts = (Amperes)2 x Resistance or
Watts = (Voltage)2 / Resistance

For more info, see Electrical Technology site's article on Power Formulas in DC and AC Single-Phase & Three-Phase Circuits

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The prefix " kilo " means:

(A). To multiply by 1000 whatever quantity follows

Kilo means a thousand, or 10 to 3rd power, or 10x10x10

For more info, see Wikipedia's article on Kilo-

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The prefix " micro " means:

(A). Divide by 1,000,000 whatever quantity follows

Micro is a one millionth of a unit, or 10 to minus 6.
To get 10 to minus 6, move the decimal 6 positions from unit 1, or so 0.000 001

10 to minus 1 is 0.1 or deci-
10 to minus 2 is 0.01 or centi-
10 to minus 3 is 0.001 or mili-

For more info, please see Wikipedia's article on Micro-

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The factor by which the product of volts and amperes must be multiplied to obtain true power is:

(A). Power factor

Power is measured in watts, or in units of Joule per second.

Watts = Amperes x Voltage or
Watts = (Amperes)2 x Resistance or
Watts = (Voltage)2 / Resistance

For more info, see Electrical Technology site's article on Power Formulas in DC and AC Single-Phase & Three-Phase Circuits

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The prefix " meg " means:

(A). Multiply by 1,000,000 whatever quantity follows

Mega is the unit multiplied by 10 to 6th power. (10)6, which is 10x10x10x10x10x10 = 1,000, 000

For more info, see Wikipedia's article on Mega-

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Factors which influence the resistance of a conductor:

(D). All of the above

• Cross-sectional area
• Length
• Temperature

The resistance of a conductor is affected by:

• the amount of cross-section area in inverse proportion
  
• the length of a conductor in direct proportion
  
• most conductors, not all, increase resistance as the temperature goes up
  
• type of conductor material.
  

For more information, see Engineering Educators site article on Factors Affecting Resistance

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Halving the cross-sectional area of a conductor will:

(A). Double the resistance

The resistance of a conductor is affected by:

• the amount of cross-section area in inverse proportion
  
• the length of a conductor in direct proportion
  
• most conductors, not all, increase resistance as the temperature goes up
  
• type of conductor material.
  

For more information, see Engineering Educators site article on Factors Affecting Resistance

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Name four conducting materials in order of their conductivity.

(B). Silver, gold, zinc, platinum

For more information, see Engineering Educators site article on Factors Affecting Resistance the "Figure 41. Resistivity table," for measurements of resistivity.

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Good insulators at radio frequencies are

(D). A & B

• Pyrex, mica
• Isolantite, steatite, polyethylene

What makes a good insulator is not just lack of conductivity, but also the effect of sunlight, especially ultraviolet waves (being highly energetic) they degrade the insulating material.

Well illustrated info on ThoughtCo article 10 Examples of Electrical Conductors and Insulators Things That Don't Conduct Electricity and Things That Do

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A resistance across which a constant voltage is applied is doubled. What power dissipation will result?

(A). One half

The resistance of a conductor is affected by:

• the amount of cross-section area in inverse proportion
  So, if you double the resistance, the loss of energy will be the reciprocal, or 1 over double (1/2), or one-half.
  
• the length of a conductor in direct proportion
  
• most conductors, not all, increase resistance as the temperature goes up
  
• type of conductor material.
  

For more information, see Engineering Educators site article on Factors Affecting Resistance

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The needle of a magnetic compass when placed within a coil carrying an electric current:

(D). A & B

• Will tend to become parallel with the axis of the coil
• Will point to the north pole end of the coil

For more details, please see Siyavula Technology-Powered Learning site, article on 10.2 Magnetic field associated with a current

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Electrical resistance is measured with:

(A). An ohmmeter

The meter measures how much a substance prevents the flow of electrons (current) through its surface skin, known as the electrical resistance, and expressed in ohm units.

For more info, see Elprocus site, for article on What is an Ohmmeter? Circuit Diagram, Types and Applications

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The sum of all voltage drops around a simple DC circuit, including the source, is:

(A). Zero

That is just the definition of changes in voltage in a simple DC circuit. This called the Kirchhoffs' Voltage Law, or the Law of Conservation of Energy.

The law declares that:

"'in any closed loop network, the total voltage around the loop is equal to the sum of all the voltage drops within the same loop.'”

This means that if you sum all the volts in the components, the sum will be zero.

For more info, see Electronics Tutorials site, article on Kirchhoffs Circuit Law

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If a resistance to which a constant voltage is applied is halved, what power dissipation will result?

(A). Doubled

The resistance of a conductor is affected by:

• the amount of cross-section area in inverse proportion
  So, if you half the resistance, the loss of energy will be the reciprocal, or 1x2 over 1 (2/1), or double.
  
• the length of a conductor in direct proportion
  
• most conductors, not all, increase resistance as the temperature goes up
  
• type of conductor material.
  

For more information, see Engineering Educators site article on Factors Affecting Resistance

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The diameter of a conductor six inches long is doubled, what will be the effect on the resistance?

(D). A & C

• One-fourth the original value

• The resistance varies inversely with the cross-sectional area of the conductor

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A minute subdivision of matter having the smallest known unit of negative electrical charge is:

(A). Electron

If you have more negative electrons than positive protons, then you have a negative electric charge.

For more info, please see Wikipedia's articles on Electron and Electric charge

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Conductors differ from nonconductors, i.e.:

(D). A & B

• There are a large number of free electrons in a good conductor

• There is a small number of free electrons in a non-conductors stop the flow of electrons.

Conductors facilitate flow of electrons across their skin surface, while nonconductors do not allow the

Conductance is the opposite of resistance. The resistance is measured in Ohms, but conductance is measured in Mho's. The Mho, is the 1/ohm, that is the Mho is the reciprocal of Ohm.

For more info, please see ElectronicNotes' site article Electrical Conductivity: mho, siemens

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Direction of flow of DC electricity in a conductor can be determined by:

(D). A & C

• A magnetic compass and the left hand rule
• Connecting an ammeter with marked polarities in series with the circuit

Direct Current occurs when electrons flow in a one direction only. Electronic circuits use mostly direct current from a battery or a direct current transformer.

More info on Wikipedia's article on Direct current

The flow of electrons in the same direction (DC current) creates a magnetic field. The magnetic field propagates clockwise around the surface skin of the conductor material. The compass needle will be affected by the magnetic field.

More info on Wikipedia's article on Magnetoresistance

By introducing a magnetic field to a flow of electrons in one direction, there will be created a force that is at 90 degrees (perpendicular) to the magnetic field and the flow of electrons.

On a graph, this force would be on the Y axis, while flow and magnetic force on the X axis. For simplicity, your thumb would be the force, while the index finger would show the magnetic force, while the middle finger would show a flow of electrons.

More info on Wikipedia's article on Magnetoresistance

There are various versions of the interaction of force, magnetic field, and current. Mostly, they are called either a left-hand or right-hand rule. These two are opposite of each other.

The left-hand rule shows the flow of current to produce motion, as in electric motors. The right-hand rule is the opposite, as it creates current, not using it, in generators of electricity.

See detailed explanation on Wikipedia's article Fleming's left-hand rule for motors

In the past, an instrument called "Galvanometer" was used to measure DC current. An improved version which did not require interrupting the electrical circuit is called an "Ammeter" It measures current in amperes.

For more info, please see Wikipedia's article on Ammeter

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The difference between electrical power and electrical energy is:

(C). A & B

• Electrical power is the rate of doing work by electricity
• Electrical energy is the ability to accomplish work by electricity

Good simple definitions.

For more info, please see Wikipedia's articles on Electric power
and Electrical energy

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A positive temperature coefficient means:

(C). Both A & B

• Resistance increases as the temperature increases
• Resistance decreases as the temperature decreases

For greater insights, please see Wikipedia's article on Temperature coefficient

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A liquid which is capable of conducting electricity, but undergoes decomposition while doing so is:

(A). An electrolyte

Liquids with the ability to allow flow of current is called an electrolyte.

For more details, please see Wikipedia's article on Conductivity (electrolytic)

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The effective value of an RF current and the heating value of the current are:

(A). The same

For greater insights, please see Wikipedia's article on Temperature coefficient

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One horsepower is:

(D). All of the above

• 746 Watts
• Roughly 3/4 kilowatt
• Corresponds to lifting 550 pounds at the rate of one foot per second

The horsepower measurement reflects the amount of work done as one unit. There are several different horsepower measurement.

For more info, please see Wikipedia's article on Horsepower

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What factors determine the heat generated in a conductor?

(C). Both A & B

Heat generated in a conductor is:

• directly proportional to the resistance
• directly proportional to the square of the current

For greater insights, please see Wikipedia's article on Temperature coefficient

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What is the ratio of peak to average value of a sine wave?

(D). A & B

• 1.57 to 1
  
• 1 to 0.636
  

There are a number of formulas for calculating the avg value of sine wave for different waves. The 1.57 refers to the "half wave rectified sine wave." The "full rectified wave" is 0.637.

For more details, see Electrical Technology site, article on RMS Value, Average Value, Peak Value, Peak Factor And Form Factor in AC

and, site All About Circuits article on Measurements of AC Magnitude

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When the current sine wave in a circuit reaches its peak value before the voltage wave:

(A). It is said to have a leading power factor

When the electron flow (amperes) is at max before the max in amount of charge (electrons) differential (volts), then we have a leading power factor.

Power is the ability of voltage (push) and amperes (electron flow) to do a unit of work. If you apply root-means-square formula to the amperes and volts, you get "apparent power."

If you imagine that horizontal line is the real power, and at an angle from that line is another line, called apparent power, then the difference between apparent power and real power is the reactive power. (such a fun fact)

If the apparent power line is below the horizontal real power line, then we have the leading power factor If the apparent power line is at an angle above the horizontal real power line, then we have lagging power factor.

"Capacitive loads are leading (current leads voltage), and inductive loads are lagging (current lags voltage)."*

*For more insights, please see Wikipedia's article on Power Factor

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An "harmonic" is:

(A). A whole multiple of an original frequency

Harmonic is the same note, but some octaves higher. The wave from zero to max back to zero is divided by a number such as 1,2, or 3 or more.

When you divide the wave it occurs at a higher Hz, at a multiple of the initial Hz wave. So, if the initial wave is at 440 Hz, then the second harmonic will be at 880 Hz, and there will be two waves in the time unit of the initial one.

The 3rd harmonic will have three smaller waves in the time unit of the initial wave, and the initial frequency in Hz will be multiplied by 3.

Harmonics are important in music and radio waves. In radio waves, there are circuits to eliminate the harmonics of the frequency desired, to suppress interference.

For more info, please see Wikipedia's article on Harmonic

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Assuming a power source to have a fixed value of internal impedance, maximum power will be transferred to the load when:

(A.) The load impedance equals the internal impedance of the source

Impedance is the resistance to alternating current. Impedance is created by the resistance (opposition to flow of electrons, in ohms) and reactance. Reactance includes inductive and capacitive components.
See Wikipedia's article on Electrical Impedance

Impedance matching seeks to maximize the amount of power transferred while minimizing the reflection from the load transferred.

Basically, if the impedance of the input load is the same as the internal impedance of the output (the source), then the maximum amount of power is transferred.
For more info, see Wikipedia's article on Impedance matching

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When two sine waves of the same frequency do NOT reach their maximum or minimum values simultaneously:

(D). A & C

• A phase difference exists
• The sign waves are out of phase

Alternating current creates a sine wave as electric motor rotates between north and south magnetic poles in a coil. See Electronic Tutorials Sinusoidal Waveforms article.

When voltage sine wave leads current (ELI) inductance is the result. When current sine wave leads voltage (ICE), then result is capacitance.
(ELI the ICE man)
E voltage, L inductor, I current;
I current, C capacitor, E voltage

Please see Wikipedia's animated illustration on the relationship of Phases and Sine waves. You can see that when there is no phase difference, the combined sine wave is at maximum.

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Which method may be used to obtain more than one value of voltage from a fixed DC source?

(C). Both A & B

• Use a resistance type voltage divider

• Connect voltage regulator tubes of suitable values and tap off the desired output voltage

For insights regarding DC current, please see IQS Directory site's article on DC Power Supply

For well illustrated practical application of variable DC current, please see How To Get Variable Voltage From a Fixed DC Power Supply

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The conductance (G) of a circuit if
6 A flows when
12 VDC is applied is:

(A). 0.5 mho

mho is the 1/ohms yielding conductance.

Conductance (G), is 1/R or I/V.

G = 6 A / 12 VDC = 0.5 mho

For more info, please see Wikipedia's article on Electrical resistance and conductance

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Two (2) 10 W,
500 ohm resistors
in parallel will dissipate how many watts?

(A). 20 watts

Formulas for power dissipation:

Watts = Volts x Amperes or
Watts = Volts(2) / Ohms or
Watts = Amperes(2) x Ohms

Because both resistors in parallel are the same value:
2 quantity (each 500 ohms) x 10 Watts = 20 Watts

For more info, please see All About Circuits site, article Power Calculations Chapter 5 - Series And Parallel Circuits

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A 20 ohm resistor with a current of
0.25 A passing through it
will dissipate how many watts?

(D). 1.25 watts

Watts = Volts x Amperes or
Watts = Volts(2) / Ohms or
Watts = Amperes(2) x Ohms

Watts = 0.25 A (2) x 20 ohms
Watts = 0.0625 A x 20 ohms
Watts = 1.25

For more info, please see All About Circuits site, article Power Calculations Chapter 5 - Series And Parallel Circuits

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If the voltage to a circuit is doubled
and the resistance is increased to three times the original value,
what will be the final current?

(B). 2/3 the original current

Voltage x 2 and Resistance * 3 ==> Amperes?

Voltage = Amperes x Ohms
Amperes = Voltage / Ohms
Amperes = 2V/3R which is 2/3 original amperes

For more info, please see Electrical 101 site article on Ohm’s Law

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If a vacuum tube with a filament rating of
0.25 A and
5 V is operated from a
6 volt battery,
what value of resistor is necessary?

(A). 4 ohms

Ohms = Volts / Amperes
Ohms = 6 volts / 0.25 Amperes = 24
Ohms = 5 volts / 0.25 Amperes = 20
24 ohms - 20 ohms = 4 ohms

For more info, please see All About Circuits site, article Power Calculations Chapter 5 - Series And Parallel Circuits

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The minimum power dissipation rating of a resistor of
20,000 ohms across a potential of
500 V should be:

(A). 25 watts

Watts = Volts(2) / ohms
Watts = 500 ohms (2) / 20,000 = 12.5 watts
12.5 watts x 2 = 25 watts

For more info, please see All About Circuits site, article Power Calculations Chapter 5 - Series And Parallel Circuits

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The total power dissipation capability of
two 10 watt,
500 ohm resistors
connected in series is:

(A). 20 watts

Formulas for power dissipation:

Watts = Volts x Amperes or Watts = Volts(2) / Ohms or Watts = Amperes(2) x Ohms

Because both resistors in parallel are the same value: 2 quantity (each 500 ohms) x 10 Watts = 20 Watts

For more info, please see All About Circuits site, article Power Calculations Chapter 5 - Series And Parallel Circuits

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What is the total power dissipation capability of
two 10 watt
500 ohm resistors
connected in parallel?

(A). 20 watts

Formulas for power dissipation:

Watts = Volts x Amperes or Watts = Volts(2) / Ohms or Watts = Amperes(2) x Ohms

Because both resistors in parallel are the same value: 2 quantity (each 500 ohms) x 10 Watts = 20 Watts

For more info, please see All About Circuits site, article Power Calculations Chapter 5 - Series And Parallel Circuits

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What is the maximum current carrying capacity of a resistor of
5000 ohms,
200 watts?

(A). 0.2 A

Watts = Volts x Amperes or
Watts = Volts(2) / Ohms or
Watts = Amperes(2) x Ohms

200 watts = 5000 ohms x X(2) Amperes

X(2) = 200 / 5000 = Square Root of 0.04 = 0.2 A

For more info, please see All About Circuits site, article Power Calculations Chapter 5 - Series And Parallel Circuits

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What is the total resistance of
a parallel circuit consisting of a
10 ohm branch and a
25 ohm branch?

(D). 7.14 ohms

To sum up parallel resistors, you need to take the reciprocal of the resistors.

1/10 + 1/25 = 0.1 + 0.04 = 0.14,
so reciprocal of 1/0.14 =7.14

For more info, please see All About Circuits site, article Parallel Resistance Calculator

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The current through two (2) resistors in series is
3 A. Resistance
#1 is 50 ohms, resistance
#2 drops 50 V across its terminals.
What is the total voltage?

(A). 200 V

Voltage = Amperes x Resistance

3 Amperes x 50 Ohms = 150 Volts
since 50 Volts drop is given,
then 150 V + 50 V = 200 V

For more information, please see Sciencing site article on How to Calculate a Voltage Drop Across Resistors

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An 18 ohm and a 15 ohm resistor are connected in parallel;
a 36 ohm resistor is connected in series with this combination;
a 22 ohm resistor is connected in parallel with this total combination.
The total current is 5 A.
What current is flowing in the 15 ohm resistor?

(A). 0.908 A

Amperes = Volts / Resistance.

1. Determine combined resistance, in parallel of 18 and 15 ohms. Use 1/x for addition of parallel resistors.
2. The series circuit adds 36 ohms. Straight addition.
3. Determine combined resistance, in parallel of 22 ohms . Again, need to use 1/x to add the previous resistance and the 22 ohms here. This is the total resistance.
4. The total current is 5 Amperes.

(1) In parallel
1/18 + 1/15 = 15/ 270 + 18 / 270 = 33 / 270 = 0.122 or about 8.18

(2) In series
8.18 + 36 = 36.122 = 44.18 ohms

(3) In parallel
44.18 ohms + 22 ohms = 14.686 ohms

(4) To derive Volts
14.686 ohms x 5 Amperes = 73.43 Volts

Then, you have to work back Amperes to the 15 ohm resistor. Calculate branch currents without voltage

Remember, Amperes flow through series unchanged, but divide in parallel, depending on the resistor.

For more info on parallel and series circuits, see BCampus site article 63 Resistors in Series and Parallel

For more information, please see Sciencing site article on How to Calculate a Voltage Drop Across Resistors

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A circuit passes 3 A.
The internal resistance of the source is 2 ohms.
The total resistance is 50 ohms.
What is the terminal voltage of the source?

(A). 150 V

The formula V=IR can be used.
3Ampers x 50 Ohms = 150 Volts

For more info, see Science by Degrees site's article Why V=IR is not Ohm’s Law, and why that matters

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A relay coil has
500 ohms resistance, and operates on
125 mA. (0.125 A)
What value of resistance should be connected in series with it to operate from 110 VDC?

(A). 380 ohms

For resistance in series circuits, you simply add resistance of each component. See Understanding & Calculating Series Circuits Basic Rules from swtc.edu

V=IR
110 V = (500 ohms + X ohms) * .125 A
(500 ohms + X ohms) = 110 v / .125 A
(500 ohms + X ohms) = 880 ohms
X = 880 ohms - 500 ohms = 380 ohms

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Given: Input power to a receiver is 75 watts. How much power does the receiver consume in 24 hours of continuous operation?

(C). A & B

• 1800 watt hours
• 1.80 kilowatt hours

Both answers are the same.
Kilo is 1000, so 1800/1000=1.80

75 Watts x 24 hours = 1,800 Watts

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The total reactance when two capacitances of equal value are connected in series is:

(B). The sum of the two individual reactances in ohms

For insight, please see Lumen Physics site the article on Resistors in Series and Parallel also Capacitors in Series and Parallel

And, from Electronics Tutorials site the article on Capacitors in Series, and Capacitors in Parallel

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A capacitor's charge is stored:

(C). A & B

• Upon the inner surface of the capacitor plates

• As an electrostatic field which exists in the space between the plates

For details, please see OPENPRESS.USASK.CA site article on 4.3 Energy Stored in a Capacitor

Also, see Lumen Physics site article on Energy Stored in Capacitors

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The voltage drop across an individual capacitor of a group of capacitors connected in series across an AC source is:

(D). All of the above

• Inversely proportional to the ratio of the capacitance of the capacitor being considered

• Inversely proportional to the total capacitance of the combination

• Directly proportional to the applied voltage across the series combination

For more info, please see Electronics Tutorials site article Capacitors in Series

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What is the total capacitance of the capacitors of 3, 5, and 7 microfarad connected in series?

(B). 1.479 microfarad

1/3 is 0.33333333333
1/5 is 0.2
1/7 is 0.14285714285

The total is 0.67619014285 and the reciprocal 1/67619014285 is 1.479

For more info, see Lumen Physics article on Capacitors in Series and Parallel

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If capacitors of 3, 5, and 7 microfarad are connected in parallel, what is the total capacitance?

(A). 9 microfarad

The formula calls for simple addition, which comes to 15, and not 9. Seems like an error. Best, just remember that answer. Checked in the FCC Element 6 question pool, and it is 9.

For more info, see Lumen Physics article on Capacitors in Series and Parallel

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How many capacitors of
400 volts and
2 microfarad each would be necessary to obtain a combination rated at
1600 volts and
1.5 microfarad?

(B). 12

Please see Physics Forum site for explanation of the answer.

See DigiKey Electronics for Series and Parallel Capacitor Calculator

See Open Press site for 6.3 Kirchhoff’s Rules

For basic info, see Electronics Tutorials site for Capacitance and Charge

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If a turn in an inductor is shorted:

(D). All of the above

There will be:

• decrease of induction
• a decrease of Q
• overheating with possible burnout

The question does not specify whether it is a DC or AC circuit. One property of an inductor is that it resists changes in amperes.

However, the inductance to the flow of amperes is not the same in DC and AC circuits, measured in di/dt, or change in amperes per change in a unit of time. In DC circuits, the coil stores energy, in AC circuits, the coil stores and delivers energy.

Because of the change (decrease in induction), the flowining amperes may overheat the circuit.

Coils do have some resistance, Q, and short may cause a decrease in Q, as it causes some energy loss.

For more info on inductors (chokes), please see Electronic Tutorials site for article on The Inductor

and for even more details, please see Voltech website for the article on Methods for Detection of Shorted Windings

Regarding Q in coils, please see Electronics Notes article on Inductor Q, Quality Factor

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The relationship between the number of turns and the inductance of a coil may be expressed by:

(A). The inductance varies approximately as the square of the number of turns

For more info, please see Quora article on Why is inductance (L) proportional with turns-square (N²)?

and Electronics Tutorial article on Inductance of a Coil

For more info on inductors (chokes), please see Electronic Tutorials site for article on The Inductor

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The formula for determining the resonant frequency of a circuit when the inductance and capacitance are known is:

(C). Both A & B

• f = 1/(2 pi times the square root of LC)

• f = 0.159/(the square root of LC)

When you graph frequency on X axis, and reactance on Y axis, the inductive reactance is a straight 45 degrees line, but the capacitive reactance curve starts high and decreases as frequency increases.

At the intersection of both, there is the resonant frequency for a specific circuit. It is when the inductive and capacitive reactance are equal. For more info, please see Cadence site, article on What is Resonant Frequency?

Also, for more details see Electronics Tutorials article on Series Resonance Circuit

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The formula for determining the wavelength when the frequency is known is:

(D). All of the above

• Wavelength = 300,000/ f kHz

• Wavelength = 300,000,000/ f Hz

• Wavelength = 300/ f MHz

For graphic explanation, see wikiHow article on How to Calculate Wavelength,
and on Study site, How to Calculate Wavelength, which offers a video and info.

For explanation on metric system of units, kilo, and mega, see Wikipedia's article on Metric prefix

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The wavelength of the period of one complete cycle of a radio wave of 0.000,001 second is:

(A). 300 M

Since waves travel in vacuum at 300,000 km/second, or 3,000,000 meters per second, multiply by 1,000,000 to get the second, or 300 M (M=1,000,000).

For details, see Socratic Q&A site article on How can I calculate the wavelength of electromagnetic radiation?

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The efficiency of a radio device is:

(B). The ratio of the useful power output to the power input

Generally, efficiency of any system is the cost or amount of what is provided, and the benefits achieved.

For radio, it is the amount of energy as input, and the amount of energy as output, with the difference being radiated during the processing.

For more info, see Socratic Q&A site for How can energy efficiency be calculated?

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What is the total impedance of a parallel capacitor and inductor with equal values of reactance?

(D). B & C

• Zero total reactance
• Parallel impedance is resistive and infinite

For explanation of impedance and reactance please see Electronics Tutorial site for article on Impedance and Complex Impedance

Also, see EE Power site for article on Impedance and Reactance

Specific explanation here on Electrical Engineering article on Infinite impedance at resonance in parallel LC circuit ? does that mean it is not usable?

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The total inductance of two coils in parallel without any mutual coupling is:

(A). Equal to the product of the two inductances divided by their sum

If coupling in the circuit of two coils present, then the total amount of inductance will be affected by the total amount of coupling.

For explanation of the formula, please see Electronics Tutorial site, for the article on
Inductors in Parallel,
paragraph on the "Parallel Inductor Equation."

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What is the total reactance of a series AC circuit, with no resistance and equal inductance and capacitive reactances?

(D). All of the above

• The two reactances cancel being equal and opposite
• Net impedance is purely resistive and contains no reactive component
• The total reactance is zero at the resonant frequency

For full explanation, please see Electronics Tutorials article on AC Inductance and Inductive Reactance

Also, a great article on Reactance, Inductive and Capacitive listed on the Lumen Learning site.

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The total inductance of two coils in series without any mutual coupling is:

(A). The sum of the individual inductances

If coupling in the circuit of two coils present, then the total amount of inductance will be affected by the total amount of coupling.

For explanation of the formula, please see Electronics Tutorial site, for the article on
Inductors in Parallel,
paragraph on the "Parallel Inductor Equation."

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One wave-length is:

(C). A and B

• The distance a wave will travel in the time for one cycle

• Centimeter wavelength = 30,000 / frequency MHz

Need to watch out for the units of measure here. We know that light travels at the speed of 300,000,000 meters per second.

The standard formula for wavelength is 300,000,000 meters/second or 300M divided by radio frequency in Hz.

The time unit for the wave is a second. Thus, we state that so many waves occurred in one second.

So, if we use MHz instead of Hz, then we have to adjust the units of speed of light in the formula.

We know that 1 MHz equals to 1,000,000 Hz. And, we know that there are 100 centimeters in a meter.

Then, if we multiply the 300,000,000 meters/second by 100 centimeters/one meter, we get 30,000,000,000 centimeters/second.

To convert Hz to MHz, we must divide by 1,000,000 Hz in 1 MHz, to get 30,000 centimeters per MHz.

Please see NewHams.Info site article on Wavelength. This site is a good resource for various radio topics.

To calculate wavelengths, and try out various units, please see Wavelength Calculator site for Wavelength Calculator

BTW: A great listing of FCC radio frequency allocations is an FCC Online Table Frequency Allocations. Good to print out and keep as reference for when choosing frequencies.

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In an AC circuit, a series inductance acting alone:

(A). Causes the current to lag the applied voltage by 90 degrees

For AC inductance, it is the resistance to the change in current or amperes, expressed in Henry units. When a coil gets alternating current, it produces electrical magnetic frequency, which opposes the change in the current.

Then, volts applied through a sine wave, the volts lead current by 90 degrees, OR the current LAGS voltage by 90 degrees.

For more info, please see Electronics Tutorials site, article on AC Inductance and Inductive Reactance, subsection "Sinusoidal Waveforms for AC Inductance."

Also, see TutorialsPoint site, article on Inductors in AC Circuits.

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Shock excitation into an L-C circuit is the result of:

(D). All of the above

• A voltage being momentarily introduced
• The capacitor may be charged
• The inductor may have a voltage induced

To produce vibrations, like resonance, you have to hit it, such as a glass to sound, a guitar string to vibrate, or a bell to sound. In electrical circuits, voltage (a difference between charges in two objects) will cause a spark to jump, or a capacitor, having two plates, maybe shocked when the difference in charges exists between the plates.

For more depth info, please see the Industrial Electronics site, for the article on Guide to Crystal Oscillators -- Review of Oscillation Principles, section 4 Self-Excited L-C Oscillator Characteristics.

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The term cathode ray usually applies to:

(A). A fairly high velocity electron beam

There are two guns that shoot electron beam at a storage mash. The main beam shoots "fairly high velocity electron beam," to create the picture. The other gun illuminates the mesh by shooting the low velocity electron beam. It does not interfere with the main beam.

For more info, please see Wikipedia's article on Cathode-ray tube

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Shielding an RF inductance:

(D). All of the above

• Increases the losses of the inductance
• Lowers the inductance value and the Q
• Increases the coil capacity to the shield

When RF inductance occurs, there may be an establishment of undesirable relationship between components. A common method to prevent it is to provide shielding, which could be a physical barrier to RF inductance by absorbing radiation.

For greater insights, please see Passive Components site for article on EMI Suppression Shields: Understanding the Basics.

Also, see GCG Gowanda Components Group practical article on To Shield or Not to Shield - Part 1 It will show up in pdf format.

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The tendency of a tank circuit to keep oscillating for a time after the excitation energy has been removed is:

(B). Flywheel effect

Tank circuit was so named by radio pioneers, as it reminded them of the behavior of water when pulsing disturbance is introduced.

Now, it is often referred to as the oscillatory circuit, or LC. The letter L represents this tank or resonant circuit, and the letter C stands for a capacitor. The circuit can store energy and release through resonant vibrations.

For more info and great animation, please see Wikipedia's article on LC circuit.

The concept of the "flywheel" is taken from the potter's round stone wheel which he moves with the foot, and when stopped pushing, the wheel has stored energy due to its weight that it keeps rotating.

The continuation of oscillations in LC after input current has been removed, is similarly called the "flywheel effect."

For additional info, please see Wikipedia's article on Flywheel effect

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Power factor is defined as:

(C). Both A&B

• The ratio between the resistance and the impedance in a circuit

• The ratio between the true power and the apparent power of a circuit

While resistance is used to control the flow of electrons, impedance is a resistance that arises out of the capacitive or inductive reactance. So the ratio between the two is also called the power factor, or how much power actually gets through.

For more info, please see the Linquip Technews article on Difference Between Resistance and Impedance-Resistance vs. Impedance.

Another more practical info site is the Fluke company site article on What is power factor and why is it important?

By measuring the power factor ratio, we can determine how much of available power is actually used. Wikipedia's article called the Power factor describes it as the total available power to the combination of amperes and volts (volt is the difference in charge between two items). That is what is called the difference between the "true power" and the "apparent power."

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High or low frequency oscillations occurring in circuits other than the original tank desired output frequencies are:

(B). Parasitic oscillations

Oscillations happen when there is a change of states from A to B. It can be a regular unchanging movement which we call the sine wave. Should the movement stop, the item or current moving will find a middle point between the A and B state.

When the vibration is undesirable, such as in currents or radio waves, it is called parasitic. If you ever heard a microphone make a whining sound coming from the amplifier, you hear a mike listening to itself, or parasitic oscillations of sound. In electric systems, the EMI electromagnetic interference is called parasitic oscillation.

For more info, please see Wikipedia's article on Oscillation.

Also, an excellent concept presentation is on the ThoughtCo. website, article Oscillation and Periodic Motion in Physics.

In electric circuits, it happens when there is a connection between the output and input wiring. This is like connecting a fresh water pipe with the sewer pipe in plumbing.

For more info, please see Wikipedia's article on Parasitic oscillation.

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What are effects of parasitic oscillations?

(D). All of the above

• Change of bias
• Reduced efficiency of the amplifier tube
• Distortion of the modulated wave

If you ever heard a microphone whine in the amplifier, you heard parasitic oscillation, which is what you don't want in a feedback, or variation in current or voltage.

Whether analog or digital processing, the undesirable feedback can occur. It occurs when part of the output is processed as input.

For more info, please see Wikipedia's article on Parasitic oscillation

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The velocity of propagation of radio frequency waves in free space is:

(D). All of the above

• 300,000 meters / second or 3 x 10 (8) m/s
• 186,284 miles / second
• The same as the velocity of light in free space

The Speed of Radio Wave == frequency times wavelength.
Thus, since the speed is 300 km per second divided by Frequency in MHz will yield the wavelength.

See EverythingRF site for Wavelength to Frequency Calculator

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To double the resonant frequency of a resonant circuit:

(B). Make L and C both half their original values

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How may the Q of a parallel resonant circuit be increased?

(C). Both A and B

• Increasing coupling to the resonant circuit
• Using coil and capacitor supports of special low - loss materials

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If L and C in a parallel resonant circuit resonants at 1000 kHz are so varied that their product remains constant, what will be the resulting resonant frequency?

(C). 1 MHz

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What is the resonant frequency of a tuned circuit consisting of a 500 picofarad capacitor, a 150 microfarad tuning coil, and 10 ohms resistance?

(A). 581 kHz

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What is voltage regulation as applied to power supplies?

(A). The ratio of change in voltage between no load and full load to the full-load voltage output

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An EMF may be generated by sound waves by what principle?

(D). All of the above

• Electrostatic
• Piezo-electric
• Resistance change

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How can you correct power factor in an electrical circuit?

(D). Both A and B

• Inductance is used to correct a leading angle
• Capacitance is used to correct a lagging angle

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Permeability is:

(B). The ratio of magnetic flux density in a substance to the magnetizing force which produces it

Basically, how much a given substance can be magnetized.

For more information, please see Wikipedia's article on Permeability (electromagnetism)

And, Electronics Tutorials site for the article The Electromagnet, section Permeability of Electromagnets

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The time in seconds for a capacitor to attain 63.2 % of the applied voltage across its terminals is:

(C). Time constant

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What is the reactance of a 2-henry choke at 3000 Hz?

(B). 37,680 ohms

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If there is no resistance in either leg of a circuit with an inductance of 5 henrys in parallel with a capacitance of 1 microfarad, what is the equivalent impedance of the parallel network circuit?

B. Infinite

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What is the total impedance of a series AC circuit having a resistance of 6 ohms, an inductive reactance of 17 ohms, and zero capacitive reactance?

(C). 18 ohms

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The total impedance of a series AC circuit with an inductive reactance of 24 ohms, a resistance of 16 ohms, and a capacitive reactance of 16 ohms is:

(B). 16 ohms

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Essentials for making a good solder connection are:

(D). None of the above

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For protection of personnel handling a transmitter:

A. Ground all exposed metal parts

This is to avoid human contact with a power cable.

See GT Engineering site for article on EXPOSED CONDUCTIVE PART AND GROUNDING

For overall info on electricity on vessels, see Law Resource site for ABYC E-09: Direct Current (DC) Electrical Systems on Boats 46 CFR 183.340(b)(4)

Also, please see the Code of Federal Regulations, Title 29, Subtitle B, Chapter XVII, Part 1915, for the section 29 CFR 1915.85(a) Vessel radar and communication systems.

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The ratio of peak-to-effective voltage values of a sign wave are:

(C). Both A and B

• 1.414 to 1
• 1 to 0.707

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The opposition to the creation of magnetic lines of force in a magnetic circuit is known as:

(A). Reluctance

Basically reluctance is the opposition of magnetic force, just like resistance within an electrical circuit.

For more info, please see Electrical 4 U site for the article on Magnetic Reluctance: What is it? (Formula, Units & Applications)

Also, see Wikipedia's article on Magnetic reluctance

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The ratio of magnetic flux density to the field strength is known as:

(B). Permeability

First, magnetic flux density (field intensity) describes how strong the magnetic force is in a material.

For a good detailed description, please see Wikipedia's article on Magnetic flux

Then, permeability is how much magnetization resulted from the application of the magnetic force.

For a good detailed description, please see Wikipedia's article on Permeability (electromagnetism)

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The magnetic force which remains in a substance after the original magnetizing force has been removed is known as:

(B). Residual magnetism

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The direction of electron flow through a coil and the manner of winding the turns:

(A). Influence the direction of magnetic line of force generated by an electromagnet

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Adding an iron core to an air-core inductance:

(A). Increases the inductance

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Electromagnets are used in:

(D). All of the above

• loudspeakers
• meters
• motors

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What will be the effect of a small increase in the number of turns upon the field strength of a single layer solenoid?

(C). Both A and B

• Decrease in field strength if the coil length is increased

• Unchanged if the spacing is reduced to keep the length constant

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Can a transformer be used with direct current?

(C). Both A and B

• In general, no
• If the DC current is periodically interrupted it would be possible to use an original DC voltage source

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A tube containing either a filament or cathode structure, grid, and a plate is a:

(A). Triode

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A tube similar to a triode with the addition of a spirally wound screen grid between the plate and control grid is a:

(B). Tetrode

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Theoretical gain of a tube. The ratio of a small change in plate voltage to give a certain small change in plate current to a change in grid which would cause the same current:

(A). Amplification factor

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Effectiveness of the grid in causing changes of plate current:

(D). A & B

• Transconductance
• Mutual conductance

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The maximum negative anode voltage with respect to the cathode. It equals the DC voltage at the input to the plus the peak AC voltage applied during the nonconducting portion of the cycle of operation of the tube:

(A). Maximum inverse plate voltage

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What is the primary purpose of the control grid of the triode?

(A). To provide a means of obtaining amplification

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What is the primary purpose of the screen grid of the tetrode?

(C). Both A & B

• Reduces the grid to plate capacitance, making it unnecessary to neutralize RF amplifiers except at very high frequencies

• Makes the plate current substantially independent of plate voltage, permitting much higher values of amplification

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What is the primary purpose of the suppressor grid of a pentode?

(A). Is highly negative with respect to the plate and returns secondary emission to the plate, increasing the permissible gain and the tube efficiency

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Thoriated tungsten is usually used to make:

(A). Filaments

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In what types of circuits do beam power vacuum tubes find application?

(C). Both A & B

• As audio amplifier in the output and power stages of circuits having low to moderately high output ratings

• As an RF power amplifier

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When free electrons in a conductor acquire sufficient energy to leave the conductor and pass into the surrounding space, it is expressed as:

(B). Electron emission

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The emission of electrons from a material due to the impact of high-velocity electrons on its surface is:

(B). Secondary emission

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Characteristics of a vacuum tube operating as a class A amplifier:

(A). Low plate circuit efficiency, about 25%; practically no grid driving power; plate current flowing for 360 degrees of each cycle; practically no distortion of the output waveshape

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Characteristics of a vacuum tube operating as a class B amplifier:

(B). Plate circuit efficiency, about 50-60%; plate current flows slightly more than 180 degrees of each cycle, medium power output

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Factors which determine bios voltage of a vacuum tube:

(D). All of the above

• Class of operation, plate supply voltage, permissible distortion

• Grid signal magnitude, permissible plate dissipation, desired amplification factor

• The no-signal plate current desired, the desirability of drawing grid current

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In the usual Class A amplifier:

(A). There is no grid current

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The DC bias in a Class A amplifier:

(A). Usually is negative as measured at the grid with respect to cathode

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What is the effect of incorrect grid bias in a Class A amplifier?

(C). Both A & B

• Distortion of the output waveshape

• Possible excessive plate dissipation if the bias is too low

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The approximate efficiency of a Class A vacuum tube amplifier:

(A). 20%-30%

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The approximate efficiency of a Class B vacuum tube amplifier:

(B). 60%

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The approximate efficiency of a Class C vacuum tube amplifier:

(C). 85%

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A charge due to the accumulation of negative electrons because the plate potential cannot attract all of the electrons leaving the emitter:

(B). Space charge

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A material flashed by the application of heat after the tube is evacuated that absorbs any gases remaining inside the tube:

(B). Getter

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What types of vacuum tube filaments are reactivated:

(B). Thoriated tungsten

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A tungsten filament is operated at ____ temperature than a thoriated tungsten filament:

(A). A higher

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The presence of gas within a tube is indicated:

(A). By a blue glow

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The cathode of an indirectly heated type of vacuum tube should be maintained at nearly the same potential as the heater circuit:

(C). A & B

• To reduce hum pickup into the cathode

• To prevent breakdown of the insulation between the heater and cathode

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Transmitting tube filaments should be maintained at recommended voltages:

(D). All of the above

• To realize the greatest life-expectancy

• If the filament voltage is too low, the emission will be reduced and operation of the circuit may be adversely affected

• If the voltage is too high, the filament may burn out

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Use of an AC filament supply is desirable:

(A). Mostly for practical reasons. It is easily obtainable

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If a DC filament supply is used, it is advisable to periodically reverse the polarity of the filament potential:

(A). To lengthen the life of the filament

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Bias voltage on the grid of an AF amplifier tube:

• Determines the operating conditions of the tube

• The correct value is essential for undistorted Class A output

• In power amplifiers the plate current must be limited to safe value not to exceed the rated plate dissipation of the tube

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The screen grid in a vacuum tube:

(C). A & B

• Makes it unnecessary to neutralize RF amplifiers except at very high frequencies,

• Makes it possible to obtain much higher values of amplification than with triodes

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The suppressor grid in a multielement vacuum tube:

(D). All of the above

• Is highly negative with respect to the plate

• Returns secondary electrons to the plate

• Increases the permissible gain and the efficiency of the tube

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The gain of a triode audio amplifier is a function of:

(D). All of the above

• Tube transconduction

• Plate load impedance

• Transformer step-up (if used)

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"Load" on a vacuum tube commonly refers to:

(C). A & B

• The impedance through which plate current flows to produce a useful output

• Increases as the load impedance approaches the internal plate impedance in value

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A case in which the grid is held at an excessively negative value for a period of time thereby cutting off plate current:

(A). Blocked grid

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The maximum power that can be safely and continuously dissipated in heat on the plate:

(A). Maximum plate dissipation

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Occurs when plate current equals electron emission for any given filament or cathode temperature:

(A). Plate saturation

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The most desirable factor in the choice of a vacuum tube for a voltage amplifier:

(B). A high value of transconductance

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Lack of requirement for neutralizing, except at ultra high frequencies, is an advantage of a tetrode over ____:

(A). A Triode

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Characteristics of a vacuum tube operating as a Class C amplifier:

(C). High plate circuit efficiency, up to 80%; plate current drawn in bursts; great distortion of output waveshape

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Plate current flows for less than 180 degrees (about 120 degrees when the grid bias is about twice cutoff value) in what class amplifier?

(C). C.

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Tubes operated as Class C amplifiers are not suited for audio-frequency amplifiers:

(A). Because of excessive distortion

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Low plate current may be caused by:

(D). All of the above

• Low filament emission and voltage
• Excessive bias value, shorted screen bypass capacitor
• Open grid circuit, low screen grid supply voltage

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A tuned circuit made up of inductance and capacitance is:

(A). An oscillator

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Some radio-frequency amplifiers must be neutralized:

(B). To prevent sustained oscillations from occurring in the amplifier

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