Question

The specific yield of a fine-grained material such as clay and shale is

• A. Less than or equal to 5%
• B. 6 to 10%
• C. 11 to 15%
• D. 16 to 25%

Hint:

Specific yield is the volume of water that drains out of a saturated material under gravity, expressed as a percentage of the total volume. It tells us how much of the stored water can actually be extracted.

Answer 1

The Correct Option is A

Concept:
Specific yield is the volume of water that drains out of a saturated material under gravity, expressed as a percentage of the total volume. It tells us how much of the stored water can actually be extracted.

Step 1:
Coarse materials such as gravel and sand have large interconnected pores, so water drains freely and their specific yield is high (often 20% to 30%).

Step 2:
Fine-grained materials such as clay and shale have very small pores. Most of the water is held tightly by molecular and capillary forces and does not drain under gravity. Hence their specific yield is very small, typically less than or equal to about 5%.

Answer: Option (1) — Less than or equal to 5%.