Summary
In economics, understanding costs involves analyzing how they behave in the short run and long run, influenced by factors like fixed and variable inputs. The law of diminishing returns explains how increasing a variable input with a fixed input eventually leads to decreased productivity.
- Total Cost (TC) — the expense of producing a specific output level. Example: If producing 5 units costs 2000.
- Total Fixed Cost (TFC) — costs that remain constant regardless of output level. Example: Rent for a factory that stays the same whether you produce 1 or 100 units.
- Total Variable Cost (TVC) — costs that vary directly with output. Example: Cost of raw materials like iron ore that increase as production rises.
- Average Cost (AC) — total cost divided by the number of units produced. Example: If TC is 10 per item.
- Marginal Cost (MC) — the cost of producing one additional unit. Example: If producing one more unit increases TC by 50.
- Law of Diminishing Returns — as more of a variable input is added to a fixed input, the additional output from each new input eventually decreases. Example: Adding more workers to a factory with limited machines eventually reduces output per worker.
Exam Tips
Key Definitions to Remember
- Total Cost (TC)
- Total Fixed Cost (TFC)
- Total Variable Cost (TVC)
- Average Cost (AC)
- Marginal Cost (MC)
- Law of Diminishing Returns
Common Confusions
- Confusing fixed costs with variable costs
- Misunderstanding the concept of diminishing returns
Typical Exam Questions
- What is the relationship between total cost and total variable cost? Total cost is the sum of total fixed cost and total variable cost.
- How do you calculate average cost? Average cost is calculated by dividing total cost by the quantity of output.
- Why are there no fixed costs in the long run? Because all inputs can be varied in the long run.
What Examiners Usually Test
- Understanding of cost relationships and calculations
- Application of the law of diminishing returns
- Differences between short-run and long-run costs