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ENGINEERING, TE 2024 HSC 7 MC

Which row of the table correctly identifies the types of cables?

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\(A\)

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  • 1st column is coaxial cable: cross-section has a central copper wire, surrounded by an insulating material, which is then encased in a aluminium braiding (Eliminate B and D).
  • 2nd column is fibre optic cable: cross-section has a central glass core (carrying light signals) surrounded by a glass cladding with a lower refractive index and an outer protective jacket (diagram shows multiple-fibre cable).

\(\Rightarrow A\)

ENGINEERING, TE 2023 HSC 23c

How are insulating materials used in the telecommunications industry? Include an example in your answer.   (3 marks)

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  • In the telecommunications industry, insulating materials act as a barrier to prevent the flow of electrical current to unintended paths or surfaces, thus ensuring electrical safety and environmental protection.
  • An example is polyethylene which is a versatile polymer used for cable insulation and sheathing due to its insulation characteristics, temperature resistance, and durability.

Other answers could include:

  • Epoxy resin on printed circuit board.
  • Polymer casing for telecommunication devices.

Show Worked Solution

  • In the telecommunications industry, insulating materials act as a barrier to prevent the flow of electrical current to unintended paths or surfaces, thus ensuring electrical safety and environmental protection.
  • An example is polyethylene which is a versatile polymer used for cable insulation and sheathing due to its insulation characteristics, temperature resistance, and durability.

Other answers could include:

  • Epoxy resin on printed circuit board.
  • Polymer casing for telecommunication devices.
Mean mark 59%.

ENGINEERING, TE 2018 HSC 22a

Telecommunication signals can be carried by a variety of transmission media. A common form of connection between a television set and an antenna is a coaxial cable.
 

Why is copper-coated steel used for the central wire?   (2 marks)

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  • Steel provides tensile strength.
  • Electrical conductivity is provided by the copper.
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  • Steel provides tensile strength.
  • Electrical conductivity is provided by the copper.
Mean mark 56%.

ENGINEERING, TE 2019 HSC 2 MC

Which of the following identifies TWO properties of polymers that make them better suited than ceramics for the insulation of telecommunication cables?

  1. Ease of formability and higher density
  2. Ease of formability and higher flexibility
  3. Higher resistance to abrasion and higher density
  4. Higher resistance to abrasion and higher flexibility
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`B`

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By Elimination:

  • Higher density is an undesirable property in cabling (not `A` or `C`)
  • Ceramics have higher resistance to abrasion (not `C` or `D`)

`=>B`

ENGINEERING, TE 2022 HSC 27a

Describe TWO different uses of polymers in telecommunications.   (4 marks)

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Answers could include any two of the following:

Cable protection and insulation

  • Polymers offer protection for both the cable and anyone who may come in contact with it.

Circuit components

  • Polymers are widely used internally in many telecommunication devices.

Device casings and housings

  • Polymers are a common material used for casings for devices such as TV’s and mobile phones.
Show Worked Solution

Answers could include any two of the following:

Cable protection and insulation

  • Polymers offer protection for both the cable and anyone who may come in contact with it.

Circuit components

  • Polymers are widely used internally in many telecommunication devices.

Device casings and housings

  • Polymers are a common material used for casings for devices such as TV’s and mobile phones.

ENGINEERING, TE 2022 HSC 25a

Describe how an insulation test is performed on electrical cabling.   (3 marks)

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  • The primary method of testing insulation is the use of a megohmmeter.
  • The megohmmeter is connected across the material to be tested and applies a test voltage for a sample period of around 60 seconds.
  • This allows the device to detect the amount of current leakage, measured in ohms.
Show Worked Solution
  • The primary method of testing insulation is the use of a megohmmeter.
  • The megohmmeter is connected across the material to be tested and applies a test voltage for a sample period of around 60 seconds.
  • This allows the device to detect the amount of current leakage, measured in ohms.

♦♦ Mean mark 39%.

ENGINEERING, TE 2022 HSC 22c

An engineer is selecting a suitable material for the exterior housing of a telecommunications device such as the smart watch. Justify material properties that should be considered.   (3 marks)

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Properties to be considered:

  • Hardness: To resist abrasions/scratches encountered in daily life
  • Toughness: To resist damage from sudden impacts such as falling over
  • Water resistance: Protect internal electronics from exposure to water
  • Hypoallergenic: Avoid damage to user’s skin
  • Corrosion resistance and chemical stability: Increase lifespan of smartwatch and prevent injury to user
Show Worked Solution

Properties to be considered:

  • Hardness: To resist abrasions/scratches encountered in daily life
  • Toughness: To resist damage from sudden impacts such as falling over
  • Water resistance: Protect internal electronics from exposure to water
  • Hypoallergenic: Avoid damage to user’s skin
  • Corrosion resistance and chemical stability: Increase lifespan of smartwatch and prevent injury to user