Conductors and Insulators

Basic Electricity

  • Question 1

    Given two lengths of metal wire, which one will have the least electrical resistance: one that is short, or one that is long? Assume all other factors are equal (same metal type, same wire diameter, etc.).

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  • Question 2

    Given two lengths of solid metal wire with round cross-sections, which one will have the least electrical resistance: one that is small-diameter, or one that is large-diameter? Assume all other factors are equal (same metal type, same wire length, etc.).

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  • Question 3

    What is the difference between materials classified as conductors versus those classified as insulators, in the electrical sense of these words?

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  • Question 4

    Identify several substances that are good conductors of electricity, and several substances that are good insulators of electricity.

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  • Question 5

    What naturally occurring substance is the best conductor of electricity?

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  • Question 6

    Electrical wire is often rated according to its cross-sectional diameter by a gauge scale. Which is the larger-diameter wire size, 14 gauge or 8 gauge?

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  • Question 7

    What disadvantages might there be to using undersized wire in an electrical power distribution system, where electricity is transmitted from generators (sources) to “loads” (devices requiring power) far away? What might happen if the wires we choose for this application were to have insufficient cross-sectional area?

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  • Question 8

    What disadvantages might there be to using oversized wire in an electrical power distribution system, where electricity is transmitted from generators (sources) to “loads” (devices requiring power) far away? What might be bad about using wires with more than sufficient cross-sectional area for the purpose?

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  • Question 9

    What does the breakdown voltage (also known as dielectric strength) rating for an electrically insulating substance mean?

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  • Question 10

    How much voltage can a 50 mm thick piece of mica withstand before breaking down?

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  • Question 11

    Design a circuit to test the breakdown voltage of a material.

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