Answer : The plasticity index (PI) is 12 %.
Explanation :
Plasticity index (PI) : It is a measure of the plasticity of a soil.
The plasticity index is the difference between the liquid limit and the plastic limit.
Formula used:
PI = LL - PL
where,
PI = Plasticity index
LL = Liquid limit
PL = Plastic limit
As we are given that:
Liquid limit = 32 %
Plastic limit = 20 %
Now putting all the given values in the above formula, we get:
PI = LL - PL
PI = 32 % - 20 %
PI = 12 %
Therefore, the plasticity index (PI) is 12 %.