Production function is the relationship between physical input and physical output.
Production of goods requires resources or inputs. These inputs are called factors of production named as land, labor, capital and organization.A rational producer is always interested that he should get the maximum output from the set of resources or inputs available to him. He would like to combine these inputs in a technical efficient manner so that he obtains maximum desired output of goods. The relationship between the inputs and the resulting output is described as production function in Economics.
A production function shows the relationship between the amounts of factors used and the amount of output generated per period of time.
The analysis of production function is generally carried with reference to time period which is called short period and long period.
In the short run, production function is explained with one variable factor and other factors of productions are held constant. We have called this production function as the Law of Variable Proportions or the Law of Diminishing returns.
In the long run, production function is explained by assuming all the factors of production as variable. There are no fixed inputs in the long run. Here the production function is called the Law of Returns to scale of production. As it is difficult to handle more than two variables in graph, we therefore, explain the Laws of Returns according to scale of production by assuming only two inputs i.e., capital and labor and Study how output responds to their use. Production function is expressed as Q = f(K, L).
There are two methods which are used for explaining the laws of Returns to Scale
(i) Production isoquants and
(ii) Production function with two variable inputs.
