Correct Answer - Option 1 : 1.67
Concept:
Activity of the soil is defined as the ratio of plasticity index of the soil to the percentage of particles finner than 2μ or 0.002 mm.
\({A_t} = \frac{{{I_P}}}{c}\)
Ip = Plasticity index of the soil = wL – wP
wL = Liquid limit of the soil
wP = Plastic limit of the soil
Calculation:
Ip = 25%
c = 15 %
\({A_t} = \frac{{25}}{{15}} = 1.67\)