Question

In hydrometer method of sedimentation analysis, which correction is always negative?

• A. Temperature
• B. Meniscus correction
• C. Dispersing agent correction
• D. Composite correction

Hint:

Meniscus correction is due to the curved surface of the liquid.
It is always subtracted from the observed reading.
Remember: meniscus correction is negative, while dispersing agent correction is positive.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Hydrometer method is used for particle size analysis of fine soils.
Hydrometer readings are affected by various factors.
Corrections are applied to get accurate results.

Step 2: Key Formula or Approach:
No specific formula.
Need to know the nature of each correction.

Step 3: Detailed Explanation:
Temperature correction can be positive or negative depending on temperature.
Meniscus correction is always negative.
Dispersing agent correction is usually positive.
Composite correction is a combination of all corrections.
Meniscus correction is applied because the hydrometer reading is taken at the top of the meniscus.
The actual reading should be taken at the bottom of the meniscus.
Thus, meniscus correction is always negative.

Step 4: Final Answer:
Meniscus correction is always negative in the hydrometer method.
Hence, the correct option is (B).