The distance between two brass rings in a surveyor's chain is:
Correct Answer:
A. 20 cm
🎯 Understanding the Question
In any type of surveying chain, the "distance between two brass rings" refers to the length of a single, individual link. The small brass rings connect the straight wire portions to form a complete link.
🔬 Analysis of Chain Types
To find the correct answer, we need to look at the standard specifications for common surveying chains:
- Metric Chain: This is the modern standard. The length of one link is precisely 20 cm (or 0.2 meters).
- Gunter's Chain (or Surveyor's Chain): This historical chain is 66 feet long and has 100 links. The length of one link is calculated as 66 ft / 100 links = 0.66 ft. Converting this to centimeters gives approximately 20.1 cm.
Both of the most common chain types have a link length that is either exactly or very close to 20 cm, making it the only logical choice among the options.
🖼️ Visual Aid
The image below shows the typical construction of a chain, highlighting the individual links and connecting rings.
📊 Summary of Common Surveying Chains
| Chain Type | Total Length | Number of Links | Length of One Link |
|---|---|---|---|
| Metric Chain | 20 m or 30 m | 100 or 150 | 20 cm |
| Gunter's / Surveyor's | 66 ft | 100 | ~20.1 cm (0.66 ft) |
| Engineer's Chain | 100 ft | 100 | ~30.5 cm (1 ft) |
| Revenue Chain | 33 ft | 16 | ~62.9 cm (2.06 ft) |