In hydrometer analysis for a soil massa)Both meniscus correction and d...
R = Rh' + cm ± Ct - Cd
Rh' = Observed hydrometer reading
Cm = Meniscus correction
Ct - Temperature correction
Cd = Dispersive agent correction
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In hydrometer analysis for a soil massa)Both meniscus correction and d...
Men is cuscoorrection is additive and dispersing agent correction is subtractive
In hydrometer analysis for a soil massa)Both meniscus correction and d...
In hydrometer analysis for a soil mass, both meniscus correction and dispersing agent correction play important roles in obtaining accurate results. Let's understand the significance of each correction and why they are additive or subtractive.
1. Meniscus Correction:
The meniscus correction is applied to account for the curvature of the liquid surface in the hydrometer tube. When reading the hydrometer, the meniscus appears as a curved line. This correction is necessary to accurately measure the liquid level.
- Importance: The meniscus correction ensures precise readings of the hydrometer, as it compensates for the curvature effect.
- Additive: The meniscus correction is additive because it adds to the observed reading. The correction is positive (+) when the meniscus is concave upwards, and negative (-) when the meniscus is concave downwards.
2. Dispersing Agent Correction:
The dispersing agent correction is applied when a dispersing agent, such as sodium hexametaphosphate, is added to the soil-water mixture during the analysis. This agent helps to break down the soil aggregates and disperse the soil particles uniformly in the water.
- Importance: The dispersing agent correction ensures that the soil particles are adequately dispersed, preventing them from settling prematurely and affecting the analysis results.
- Subtractive: The dispersing agent correction is subtractive because it subtracts from the observed reading. The correction is negative (-) and is applied to account for the decrease in the hydrometer reading caused by the dispersing agent.
3. Correct Answer: Option C (Meniscus correction is additive and dispersing agent correction is subtractive)
Based on the above explanations, it is clear that meniscus correction is additive because it compensates for the curvature of the liquid surface, while the dispersing agent correction is subtractive because it accounts for the decrease in the hydrometer reading caused by the dispersing agent.
Overall, both corrections are essential for accurate hydrometer analysis as they address different factors that can influence the results.
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