In a diagonal scale only _______.
Correct Answer:
C. Units, tenths and hundredths can be shown
📏 Understanding Engineering Scales
In engineering and technical drawing, a scale is used to represent large objects or distances on a smaller, manageable sheet of paper. The level of precision required determines the type of scale used.
Types of Scales
- Plain Scale: The simplest type, used to measure two consecutive units. For example, meters and decimeters, or feet and inches. It can effectively show a unit and its immediate subdivision (tenths).
- Diagonal Scale: A more precise scale used to measure three consecutive units. For example, meters, decimeters, and centimeters, or yards, feet, and inches. This allows for measurements of a unit, its tenths, and its hundredths.
- Vernier Scale: An auxiliary scale that slides along the main scale, allowing for extremely precise fractional readings.
- Comparative Scale: A pair of scales with a common Representative Fraction (RF) but graduated to read different units, such as miles and kilometers.
🔍 How a Diagonal Scale Works
A diagonal scale is an enhancement of a plain scale. It uses the principle of similar triangles to divide a small division into even smaller parts with high accuracy.
It can represent three dimensions:
- Main Unit: The largest unit, read on the main horizontal divisions (e.g., Meters).
- Sub-Unit (Tenths): The first subdivision, read on the smaller horizontal divisions (e.g., Decimeters).
- Sub-Sub-Unit (Hundredths): The finest subdivision, read vertically using the diagonal lines (e.g., Centimeters).
For example, if the main scale shows meters, the first set of subdivisions will show tenths of a meter (decimeters). The diagonal lines then divide one of those decimeter blocks into ten more parts, allowing you to read hundredths of a meter (centimeters).
📊 Plain Scale vs. Diagonal Scale
| Feature | Plain Scale | Diagonal Scale |
|---|---|---|
| Number of Units Measured | Two consecutive units | Three consecutive units |
| Measurement Capability | Units and tenths (e.g., 4.6 m) | Units, tenths, and hundredths (e.g., 4.65 m) |
| Principle | Simple linear division | Principle of similar triangles |
| Example Dimensions | Meters and decimeters; Feet and inches | Meters, decimeters, centimeters; Yards, feet, inches |