a) Production Function- It shows technological relationship between physical inputs and physical outputs.

It can be written as follows:

Q = f (f₁, f₂, f₃ ….f_n). Where Q is physical quantity produced and f₁, f₂, f₃ ….f_n are the physical quantities of different factors of production used.

b) Market period – It is defined as a very short time period in which supply of commodity cannot be changed by changing the unit of factors of production. In this case all the factors of production remain constant.

c) Total Product: - The total amount of commodity (Good) produced by employing given units of variable factors with fixed factors is called Total Product. It can be obtained by two ways: 

i) By summing up the marginal physical product derived from various units of variable factor employed.

TPP = MPP₁ + MPP₂ + MPP₃ + MPP₄ +……+MPP_n 

TPP= ΣMPP

ii) By multiplying average physical product by number of units of variable factor employed.

TPP = APP x N

d) Normal Profit - Normal profit is the minimum amount of profit which is essential to keep an entrepreneur in production in the long run.