What does the nuclear meter measure in soil analysis?

The nuclear meter is primarily used in soil analysis to measure the moisture content of the soil. This is achieved through the use of radioactive isotopes that emit gamma rays; when the rays interact with soil particles and water, the meter can detect the amount of radiation that is scattered back. The proportion of moisture affects the amount of radiation, allowing the instrument to ascertain the moisture content accurately.

While unit weight can be indirectly assessed through moisture content measurements taken by the nuclear meter, its primary function is focused on determining the moisture level in soil, which is crucial for various applications in geotechnical engineering and construction. Understanding the moisture content aids in evaluating soil stability, compaction, and overall suitability for construction projects.

Thus, the correct answer highlights the nuclear meter’s role in measuring moisture content directly, establishing it as an essential tool in soil analysis. Other options, while related to soil properties, do not correctly identify the primary function of the nuclear meter in soil testing context.