## **Core Concept**
Wind velocity, an essential parameter in meteorology, is typically measured to understand weather patterns and predict changes. The standard height for recording wind velocity is crucial for ensuring consistency and comparability of data across different locations. This measurement is vital for weather forecasting, aviation, and understanding environmental conditions.

## **Why the Correct Answer is Right**
The correct answer, **10 meters**, is the standard height at which wind speed is usually measured. This height is chosen because it is high enough to be above the surface friction effects but low enough to be representative of general weather conditions. The World Meteorological Organization (WMO) recommends this height for wind measurements to ensure uniformity in data collection globally.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While wind velocity can be measured at various heights, **5 meters** is not the standard height for official recordings. Measurements at this height might be used in specific studies or applications but are not universally adopted.
- **Option B:** **15 meters** is higher than the standard measurement height. Although wind velocity measurements can be taken at various altitudes, 15 meters is not the conventional reference point.
- **Option D:** **20 meters** is even higher than option B and is not recognized as a standard measurement height for wind velocity.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that wind velocity measurements are critical in various fields, including meteorology, aviation, and environmental science. The standard height of **10 meters** ensures that data is comparable and useful for a wide range of applications. Remembering this detail can help in understanding and interpreting weather data and forecasts.

## **Correct Answer:** . **10 meters**