Which of the following is NOT correct in respect of production function of a firm?

None of the above

The correct answer is option 4: None of the above

A production function represents the relationship between inputs (such as labor and capital) and the maximum possible output that a firm can produce.

Option 1: The production function of a firm is a relationship between inputs used and output produced by the firm.
This statement is correct. This is the fundamental definition of a production function. It shows how inputs (like labor, capital, land, raw materials) are transformed into output.

Option 2: For various quantities of inputs used, it gives the maximum quantity of output that can be produced. This statement is also correct. A key characteristic of a production function is that it assumes technical efficiency. This means for any given set of inputs, the production function specifies the highest possible output that can be achieved with current technology and managerial practices.

Option 3: Isoquant is just an alternative way of representing the production function. This statement is correct. An isoquant is a curve that shows all the possible combinations of two inputs (e.g., labor and capital) that yield the same level of output. Since a production function maps all input combinations to output levels, an isoquant is indeed a graphical representation of the production function for a specific output level, much like an indifference curve represents a utility function.