The output of an extra unit of an input is referred to as________

Step 1: Analyze the question The question asks for the term used for the extra output obtained when one more unit of an input is added.

Step 2: Explain the concept In production theory, the key product concepts are:

• Total product (TP): the total output from all units of an input employed.
• Average product (AP): output per unit of input, AP = TP ÷ number of units of input.
• Marginal product (MP): the additional output from employing one more unit of the input, MP = change in TP ÷ change in input.

Step 3: Work through the options

• A. Output of the input: This is vague and not a standard economic term.
• B. Marginal product of the input: The word "marginal" means "extra" or "additional", so this matches the definition exactly.
• C. Average product of the input: This is total output divided by the number of units, not the extra unit's contribution.
• D. Utility of the input employed: Utility is the satisfaction from consuming a good, and has nothing to do with production.

Example: | Workers | Total Product | Marginal Product | |---|---|---| | 1 | 10 | 10 | | 2 | 22 | 12 | | 3 | 30 | 8 |

When the third worker is added, total output rises from 22 to 30, so MP = 30 − 22 = 8 units. This is the output of the extra worker.

Step 4: Answer The correct option is B. Marginal product of the input.

Exam tip: "Marginal" always means "extra" or "additional". Marginal product is the extra output, marginal cost is the extra cost, and marginal utility is the extra satisfaction. If you see "extra unit" in a question, think "marginal".