In general, line supports should have the following properties:

Explanation:

Line Supports

Definition: Line supports are structural elements used to hold up overhead lines such as electrical transmission lines, telecommunications lines, or other types of cables. These supports ensure that the lines remain at a safe height above the ground and maintain the necessary clearance from obstacles and other structures.

Importance: The primary function of line supports is to provide mechanical stability and ensure the safety and reliability of the overhead lines. They must be designed to withstand various environmental conditions, such as wind, ice, and temperature fluctuations, while maintaining the integrity of the lines they support.

Correct Option Analysis:

The correct option is:

Option 1: (i) High mechanical strength. (ii) Light in weight without the loss of mechanical strength. (iii) Cheap in cost and economical to maintain. (iv) Longer life.

This option correctly outlines the desirable properties of line supports. Let's analyze each point in detail:

• High mechanical strength: Line supports must have high mechanical strength to bear the weight of the cables and withstand environmental forces such as wind, ice, and other loads. High mechanical strength ensures the stability and reliability of the support structure.
• Light in weight without the loss of mechanical strength: A lightweight design is advantageous for easier transportation and installation. However, it is crucial that the reduction in weight does not compromise the mechanical strength of the support. Advanced materials and design techniques can achieve this balance.
• Cheap in cost and economical to maintain: The cost-effectiveness of line supports is a critical factor, especially for large-scale installations. The initial cost should be reasonable, and the maintenance costs should be minimal to ensure long-term economic viability. This includes using materials and designs that are durable and require less frequent maintenance.
• Longer life: Line supports should have a long service life to minimize the need for replacements and reduce overall costs. This involves using materials that are resistant to corrosion, wear, and environmental degradation.

Additional Information

To further understand the analysis, let’s evaluate the other options:

Option 2: (i) Low mechanical strength. (ii) Light in weight without the loss of mechanical strength. (iii) High in cost and economical to maintain. (iv) Longer life.

This option is incorrect because low mechanical strength is not desirable for line supports. They need to withstand various loads and environmental conditions, and low mechanical strength would compromise their stability and reliability. Additionally, high cost is not ideal as it increases the initial investment and may not be justifiable in the long run.

Option 3: (i) Good appearance. (ii) Strong in weight without the loss of mechanical strength. (iii) High cost and economical to maintain. (iv) 5-year life.

This option is also incorrect. While good appearance may be a secondary consideration, it is not a primary requirement for line supports. Strong in weight is not a clear specification and could imply heaviness, which is not desirable. High cost is not ideal, and a 5-year life is too short for line supports, which should have a much longer service life to be cost-effective.

Option 4: (i) Less mechanical strength. (ii) Strong in weight without the loss of mechanical strength. (iii) High cost and economical to maintain. (iv) Longer life.

This option is incorrect because less mechanical strength is not suitable for line supports. They must have high mechanical strength to perform their function effectively. Strong in weight is again ambiguous and may imply heaviness, which is not desirable. High cost is not ideal, even if the supports are economical to maintain.

Conclusion:

In conclusion, the correct option for the properties of line supports is Option 1. Line supports must have high mechanical strength, be light in weight without losing mechanical strength, be cheap in cost and economical to maintain, and have a longer life. These properties ensure that the line supports are stable, reliable, cost-effective, and durable, making them suitable for their intended purpose of supporting overhead lines.