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ENGINEERING, TE 2025 HSC 21b

Explain why aluminium alloy wire is used as an electrical transmission medium between communications towers.   (3 marks)

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  • Aluminium alloy has a low density. This means it can support its own weight over long spans between towers, reducing cable sag.
  • Its high tensile strength enables wider spacing between towers. Consequently, fewer towers are required, reducing infrastructure costs.
  • Aluminium is significantly less expensive and more abundant than copper. As a result, it is a more economical choice for long-distance transmission networks.
Show Worked Solution
  • Aluminium alloy has a low density. This means it can support its own weight over long spans between towers, reducing cable sag.
  • Its high tensile strength enables wider spacing between towers. Consequently, fewer towers are required, reducing infrastructure costs.
  • Aluminium is significantly less expensive and more abundant than copper. As a result, it is a more economical choice for long-distance transmission networks.

ENGINEERING, TE 2023 HSC 3 MC

Why is pure copper preferred over a copper alloy in telecommunications applications?

  1. It has higher stiffness.
  2. It has better conductivity.
  3. It can be precipitation hardened.
  4. It has a better strength to weight ratio.
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\( B \)

Show Worked Solution
  • Pure copper offers lower stiffness than copper alloys (eliminate A), is work hardened (eliminate C), and generally has lower strength to weight ratios (eliminate D).
  • In telecommunications, where high conductivity is crucial for transmitting electrical signals, pure copper is the preferred choice to ensure efficient signal transmission.

\(\Rightarrow B \)

ENGINEERING, TE 2018 HSC 19 MC

Which heat-treated metal is used for contact springs in electrical switches?

  1. OFHC copper
  2. Phosphor bronze
  3. Copper beryllium
  4. Tough pitched copper
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`C`

Show Worked Solution
  • Beryllium copper is used in contact springs due to its conductivity and low sparking characteristics.

`=>C`


♦ Mean mark 47%.

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

ENGINEERING, TE 2020 HSC 21d

Electrolytic tough pitch (ETP) copper has many desirable properties that support its use in telecommunications.

In the table, provide an explanation for the importance of each of the listed properties of ETP copper.   (3 marks)
 

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  1. The electrical conductivity of ETP copper is important in telecommunications because it has low resistance. This characteristic allows for an increased efficiency of both data transfer and electricity transmission.
  2. The ductility of ETP copper is important in telecommunications because it allows the copper to be drawn into very light weight, thin and flexible wire which can be used in cables without risk of failing in a brittle manner under impact.
  3. The corrosion resistance of ETP copper is important in telecommunications because it greatly reduces the risk of systems needing to be replaced due to to the cable breaking down. It also reduces cost as the system will ideally only be installed once, instead of needing constant replacement.
Show Worked Solution
  1. The electrical conductivity of ETP copper is important in telecommunications because it has low resistance. This characteristic allows for an increased efficiency of both data transfer and electricity transmission.
  2. The ductility of ETP copper is important in telecommunications because it allows the copper to be drawn into very light weight, thin and flexible wire which can be used in cables without risk of failing in a brittle manner under impact.
  3. The corrosion resistance of ETP copper is important in telecommunications because it greatly reduces the risk of systems needing to be replaced due to to the cable breaking down. It also reduces cost as the system will ideally only be installed once, instead of needing constant replacement.

ENGINEERING, TE 2021 HSC 15 MC

Which of the following would be the most suitable material to use for a spring in a telecommunication component?

  1. Annealed copper zinc alloy
  2. Electrolytic tough pitch copper
  3. Age hardened aluminium silicon alloy
  4. Age hardened copper–beryllium alloy
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`D`

Show Worked Solution
  • Age hardened copper-beryllium alloy is used due to its conductivity, low sparking capabilities and physical capabilities of hardness and strength in high temperature conditions.

`=>D`

♦♦♦ Mean mark 29%.