On analysis of particle size distribution of a soil, it is found that D10 = 0.1 mm and D30 = 0.3 mm and D60 = 0.8 mm. The uniformity coefficient and coefficient of curvature, as given by the particle size distribution curve, are respectively:
RSMSSB JE - 2025, RSMSSB - 2025,
Answer: D
The coefficients are 8 and 1.125.
Use the standard definitions:
\[ \begin{aligned} C_u &= \frac{D_{60}}{D_{10}} = \frac{0.8}{0.1} = 8 \\ C_c &= \frac{D_{30}^{2}}{D_{10} \times D_{60}} = \frac{0.09}{0.08} = 1.125 \end{aligned} \]
Since \(C_u > 6\) and \(C_c\) lies between 1 and 3, a sand with these values is well graded. 2.67 is \(D_{60}/D_{30}\), the wrong pair of sizes for \(C_u\), and 3 is \(D_{30}/D_{10}\), not the curvature coefficient.
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