The Theory of the Firm under Perfect Competition | Class 12 Economics Notes

4.5 DETERMINANTS OF A FIRM'S SUPPLY CURVE

A firm's supply curve depends on factors that affect its marginal cost curve since the supply curve is essentially the rising part of the marginal cost curve above certain cost thresholds. Two key determinants are technological progress and input prices. Technological progress allows the firm to produce more output with the same inputs or the same output with fewer inputs, lowering marginal cost at all output levels. This shifts the marginal cost curve downward or to the right, causing the supply curve to shift rightward, meaning the firm supplies more output at any given price. Conversely, an increase in input prices raises the cost of production, increasing marginal cost at all output levels. This shifts the marginal cost curve upward or to the left, causing the supply curve to shift leftward, meaning the firm supplies less output at any given price. Additionally, the imposition of a unit tax per unit of output raises the firm's marginal and average costs by the tax amount, shifting the supply curve leftward. These factors illustrate how changes in production technology, input costs, and government policies influence firm supply decisions.

📊 Diagram: See figure_14: Fig. 4.11 showing LRAC and LRMC curves before and after unit tax; figure_15: Fig. 4.12 showing supply curves before and after unit tax.

🧪 Activity: No specific activity in this section.

🔗 Connection: Leads to aggregation of individual supply curves into market supply curve in section 4.6.