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Subelement B-005

B-005

Section B-005-002

Section B-005-002

Which of these groups lists three good electrical conductors?

  • Copper, aluminum and paper
  • Gold, silver and wood
  • Copper, gold and mica
  • Correct Answer
    Gold, silver and aluminum

Wood, paper and mica do NOT conduct electricity. The best conductors, in descending order, are silver, copper, gold and aluminum.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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Which of these groups lists three good electrical insulators?

  • Wood, copper and porcelain
  • Plastic, wood and carbon
  • Teflon, mica and aluminum
  • Correct Answer
    Glass, air and porcelain

Copper and aluminum are CONDUCTORS. Carbon is a poor conductor, it is used to fabricate resistors.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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What do we call the flow of electric charge in a circuit?

  • Correct Answer
    Current
  • Voltage
  • Resistance
  • Capacitance

Current is the flow of electrons (charged particles) in a circuit. Voltage is the force that pushes the electrons. Resistance is the opposition encountered.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

What is the best conductor among the following materials?

  • Correct Answer
    Copper
  • Carbon
  • Aluminum
  • Silicon

The best conductors, in descending order, are silver, copper, gold and aluminum. Carbon is a poor conductor, it is used to fabricate resistors. Silicon is used to make 'semiconductors'.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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Which of these types of materials readily allows the flow of electric current?

  • Semiconductor
  • Dielectric
  • Insulator
  • Correct Answer
    Conductor

As the name implies, a 'conductor' readily passes electrical current. An Insulator ( synonym = dielectric ) does not let current flow. A resistor conducts but badly.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

What electrical property causes an object to conduct electricity very well?

  • Correct Answer
    Low resistance
  • Low capacitance
  • Low reluctance
  • Low admittance

Conductors have LOW resistance. They do not oppose current flow.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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The letter "R" is the symbol for:

  • Correct Answer
    resistance
  • reluctance
  • impedance
  • reactance

R = Resistance, Z = Impedance, X = Reactance.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

What is the inverse of resistance?

  • Reactance
  • Reluctance
  • Correct Answer
    Conductance
  • Permeability

Reciprocal = 'the inverse of something'. 1 over resistance yields CONDUCTANCE. Low resistance implies high conductance. High resistance implies little conductance.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

What is a voltage drop?

  • Correct Answer
    The loss of voltage caused by the flow of current through a circuit
  • Any point in a circuit that has zero voltage
  • The difference in voltage at the output terminals of a transformer
  • The voltage output of a step-down transformer

As current flows through electronic components, some voltage is 'lost'. Remember voltage as 'pressure', there is more 'pressure' before a resistor than after it: this represents a 'voltage drop'.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

The resistance of a conductor changes with:

  • Correct Answer
    temperature
  • voltage
  • current
  • humidity

Temperature affects components and conductors.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

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Which term describes the direction of current in a DC circuit?

  • Phase
  • Correct Answer
    Polarity
  • Polarization
  • Directivity

When connecting an electronic circuit to a source of DC voltage, you must respect the polarity: i.e., positive terminals together and negative terminals together.

Original copyright; explanations transcribed with permission from Francois VE2AAY, author of the ExHAMiner exam simulator. Do not copy without his permission.

Tags: none

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