Chapter 13: Producer’s Equilibrium and Supply
Producer’s Equilibrium (MR-MC Approach)
A producer is in equilibrium when they are producing that level of output where their profits are maximized, and they have no incentive to change their production level.
According to the MR-MC approach, two conditions must be fulfilled for producer’s equilibrium:
- MR = MC: Marginal Revenue must equal Marginal Cost. At this point, the firm’s total profits are maximized.
- MC must be rising beyond the point of equilibrium: MC must cut MR from below. If MC is falling and equals MR, producing another unit will add more to revenue than to cost, meaning profits can still increase. Equilibrium is only stable when MC rises after equaling MR.
Supply and its Determinants
Supply refers to the quantity of a commodity that a firm is willing and able to offer for sale at a given price during a given period.
Determinants of Supply include:
- Price of the commodity
- Prices of related goods
- Prices of factors of production (input costs)
- State of technology
- Government policy (taxes and subsidies)
Supply Schedule and Supply Curve
A Supply Schedule shows various quantities of a commodity offered for sale at different alternative prices. A Supply Curve is the graphical representation of the supply schedule. According to the Law of Supply, keeping other factors constant, as the price of a commodity increases, the quantity supplied increases. This gives the supply curve a positive (upward) slope.
Price Elasticity of Supply (\(E_s\))
Price elasticity of supply measures the responsiveness of the quantity supplied to a change in price. $$ E_s = \frac{%\text{ change in quantity supplied}}{%\text{ change in price}} = \frac{\Delta Q}{\Delta P} \times \frac{P}{Q} $$
Competency-Based Questions
Application-Based Question
Q1. The government imposes a heavy environmental tax on factories producing plastic bags. Analyze the impact of this tax on the supply curve of plastic bags using economic reasoning.
Answer: Imposing a tax increases the cost of production for the manufacturers. As the cost of producing plastic bags increases, the firm’s profit margin drops at the existing market price. Consequently, producers will be willing to supply fewer plastic bags at any given price. Graphically, this is represented as a leftward shift in the supply curve (Decrease in Supply).
Analytical Question
Q2. A firm observes that at 40 units of output, MR = ₹10 and MC = ₹10. At 41 units, MR = ₹10 and MC = ₹8. Is the firm at equilibrium at 40 units? Justify your answer using the MR-MC approach.
Answer: No, the firm is not in equilibrium at 40 units. Reasoning: While the first condition of equilibrium (MR = MC) is fulfilled at 40 units (₹10 = ₹10), the second condition is violated. The second condition states that MC must be rising beyond the point of equilibrium. However, at 41 units, MC falls to ₹8 while MR remains ₹10. This implies that producing the 41st unit brings more revenue (₹10) than it costs (₹8), thereby adding ₹2 to total profits. A rational producer will continue to expand output to increase profits until MC rises and equals MR again.