ANS:B - 5° to 20°

Theoretically, a pure clay would have a value of 0° and Π would rise with increasing sand content and density to approximately 40° for a compact sandy loam soil. Loose sands range between 25 to 30°. As pure clays are rarely found in topsoils the typical value for a \'clay\'
soil would be in the range 5 to 10° Angle of internal friction:

Rock 30°.
Sand 30-40°.
Gravel 35°.
Silt 34°.
Clay 20°.
Loose sand 30-35°.
Medium sand 40°.
Dense sand 35-45°.
Gravel with some sand 34-48°.
Silt 26-35°.