(L, C, N) Q = Quantity of output L = Labour C = Capital N = Land The level of output (Q) depends on the quantities of different inputs (L, C, N) available to the firm. In the simplest case, where there are only two inputs, labour (L) and capital (C) and one output (Q), the production function becomes. Q =f (L, C) The production function is a technical or engineering relation between input and output. If the natural laws of technology remain unchanged, the production function remains unchanged. Features of Production Function The production function consists of 3 main features – Substitutability, Complementarity and Specificity. 1. Substitutability: By changing the number and amount of some inputs, while the others stay unchanged, we achieve the possibility, to modify the total output. It is the substitutability of the factors of production that gives rise to the laws of variable proportions. 2. Complementarity: is that two or more inputs are to be used together as nothing will be produced if the quantity of either of the inputs used in the production process is zero. Another example of complementarity is the principles of returns to scale of inputs as it reveals that the quantity of all inputs has to increased simultaneously in order to attain a higher scale of total output. 3. Specificity: Every product has its own specific number and type of inputs. Machines and equipment's, specialized workers and raw materials or commodities are a few examples of the specificity of factors of production. This reveals that in the production process none of the factors can be ignored and in some cases ignorance to even slightest extent is not possible if the factors are perfectly specific. Production consists of time; hence, the way the inputs are combined is determined to a large extent by the time period under consideration. The greater the time period, the greater the freedom the producer must vary the quantities of various inputs used in the production process. In the production function, variation in total output by varying the quantities of all inputs is possible only in the long run whereas the variation in total output by varying the quantity of single input may be possible even in the short run. See also Human capital Capital (economics) Capital good References Capital (economics)