Question

What type of production function is one in which only one input is increased and others are kept constant? State the behaviour of total product in this production function.

Answer 1

This is "Variable Proportions" production function.
The behaviour of total product (TP) in this type of production function passes through three different phases, as below:
(i) Phase I: TP increases at an increasing rate. This corresponds to increasing returns to a factor.
(ii) Phase II: TP increases at a diminishing rate. This corresponds to diminishing returns to a factor.
(iii) Phase III: TP tends to fall. This corresponds to negative returns to a factor.