Explain the Law of Variable Proportions with the help of total product and marginal product curves.

Explanation

Explanation
According to the Law of Variable Proportions when only one input is increased while others are held unchanged , MP and TP change in the following manner :
Phase -I : MP increases and TP increases at increasing rate i.e. upto A on TP curve (upto K on MP curve) because there is under utilization of the fixed input .
Phase -II : MP decreases but is positive and TP increases at decreasing rate i.e. upto B on TP curve (upto L on MP curve ) because there is pressure on fixed input
Phase-III : MP decrease and is negative and TP falls i.e. after B on TP curve (after L on MP curve ) because there is too much of variable input in relation to fixed input.