Study Notes
Competitive market equilibrium occurs when market demand equals market supply, resulting in no tendency for change. The price mechanism helps achieve this by adjusting prices through demand and supply interactions.
- Market Equilibrium — the price and quantity where demand equals supply. Example: At $5, quantity demanded equals quantity supplied.
- Excess Demand (Shortage) — when quantity demanded is greater than quantity supplied. Example: At $2, demand is 160 units, supply is 40 units.
- Excess Supply (Surplus) — when quantity supplied is greater than quantity demanded. Example: At $8, supply is 160 units, demand is 40 units.
- Price Mechanism — a system where prices adjust to allocate resources efficiently. Example: Rising prices signal producers to increase supply.
- Consumer Surplus — the difference between what consumers are willing to pay and what they actually pay. Example: Area below demand curve and above price line.
- Producer Surplus — the difference between the price producers receive and the minimum they are willing to accept. Example: Area above supply curve and below price line.
- Community Surplus — total welfare from a transaction, sum of consumer and producer surplus. Example: Maximized at market equilibrium.
- Allocative Efficiency — when resources produce the most desirable goods and services. Example: Occurs at market equilibrium where P = MC.
Exam Tips
Key Definitions to Remember
- Market Equilibrium
- Excess Demand (Shortage)
- Excess Supply (Surplus)
- Price Mechanism
- Consumer Surplus
- Producer Surplus
- Community Surplus
- Allocative Efficiency
Common Confusions
- Confusing excess demand with excess supply
- Misunderstanding how price changes affect equilibrium
Typical Exam Questions
- What is market equilibrium? Market equilibrium is where demand equals supply.
- How does the price mechanism work? It adjusts prices to allocate resources efficiently.
- What happens when there is excess demand? Prices rise to eliminate the shortage.
What Examiners Usually Test
- Ability to define and explain market equilibrium
- Understanding of how changes in demand and supply affect equilibrium
- Calculation of consumer and producer surplus