Economic Curves — Set 3

Correct Answer: B. Long Run Average Cost Curve

• **Long Run Average Cost (LRAC) Curve** = shows the minimum possible average cost for each level of output when all inputs (including capital) can be varied. • **Envelope Curve** — the LRAC 'envelopes' or wraps around all Short Run Average Cost (SRAC) curves, forming a smooth U-shape. • 💡 Wrong-option analysis: [Option A] Fixed Cost Curve is a horizontal line showing constant cost regardless of output; [Option C] Short Run Average Cost Curve assumes at least one input is fixed; it cannot represent minimum long-run cost; [Option D] Marginal Cost Curve shows additional cost of one more unit, not the minimum average cost at all output levels.

Correct Answer: D. Minimum Cost

• **Minimum Cost** = when MC intersects ATC from below, ATC is at its lowest point, representing the most technically efficient scale of production. • **Mathematical rule** — when MC < ATC, average falls; when MC > ATC, average rises; they are equal only at the minimum of ATC. • 💡 Wrong-option analysis: [Option A] Maximum Profit occurs where MC = MR (Marginal Revenue), not where MC = ATC; [Option B] Maximum Revenue occurs at unit elasticity of demand, not at the MC-ATC intersection; [Option C] Break-even point in accounting means TR = TC, which is different from the cost-curve intersection.

Correct Answer: A. Lorenz Curve

• **Lorenz Curve** = can represent the distribution of any asset—including land—by plotting cumulative percentage of households against cumulative percentage of the asset held. • **Land reform analysis** — a highly bowed Lorenz Curve for land indicates severe concentration; this is used by policymakers to justify and evaluate land reform measures. • 💡 Wrong-option analysis: [Option B] Laffer Curve relates tax rates to revenue, not asset distribution; [Option C] Kuznets Curve shows the inequality-development relationship over time, not a snapshot distribution; [Option D] Engel Curve relates income to expenditure on a specific good.

Correct Answer: B. Phillips Curve

• **Phillips Curve** = the Misery Index (inflation rate + unemployment rate) uses both axes of the Phillips Curve — inflation on one axis and unemployment on the other. • **Arthur Okun** — economist Arthur Okun coined the term 'Misery Index' in the 1970s to measure economic distress faced by ordinary citizens. • 💡 Wrong-option analysis: [Option A] Engel Curve tracks income vs. expenditure on a specific commodity; [Option C] Laffer Curve tracks tax rates vs. government revenue; [Option D] Lorenz Curve tracks income/wealth distribution among a population.

Correct Answer: B. Oligopoly

• **Oligopoly** = the Kinked Demand Curve model explains price rigidity in oligopolistic markets, where few large firms dominate. • **Asymmetric competitor response** — rivals follow price cuts (to avoid losing market share) but do not match price increases, creating a 'kink' at the prevailing price. • 💡 Wrong-option analysis: [Option A] Monopoly has no rivals to create a kink; the monopolist sets price freely on the demand curve; [Option C] Perfect Competition has no price rigidity — firms are price takers with horizontal demand curves; [Option D] Monopolistic Competition has many firms with differentiated products; price rigidity is less pronounced than in oligopoly.

Correct Answer: A. Pareto Efficiency

• **Pareto Efficiency** = the Contract Curve connects all points where two consumers' indifference curves are tangent, meaning no further trade can improve one without harming the other. • **Edgeworth Box** — a diagrammatic tool that shows all possible allocations of two goods between two consumers; the Contract Curve runs through the Pareto-optimal points within this box. • 💡 Wrong-option analysis: [Option B] Production Efficiency is depicted by the production contract curve in producer theory, not the consumption Contract Curve; [Option C] Market Disequilibrium refers to excess demand or supply, not a Contract Curve concept; [Option D] Consumption Inefficiency describes points off the Contract Curve, not on it.

Correct Answer: C. Indifference Curve

• **Indifference Curve** = used with the budget line to decompose a price change into the Substitution Effect (movement along the original IC) and Income Effect (shift to a new IC). • **Hicksian decomposition** — John Hicks developed this technique using indifference curves and budget lines to separate the two effects of a price change. • 💡 Wrong-option analysis: [Option A] Supply Curve shows the producer's response to price changes, not consumer income and substitution effects; [Option B] Demand Curve shows the aggregate result of price changes but does not break them into income and substitution components; [Option D] Laffer Curve relates tax rates to government revenue, unrelated to consumer effects of price changes.

Correct Answer: C. Straight line from the origin

• **Straight line from the origin** = in perfect competition, price is fixed (the firm is a price taker), so total revenue rises proportionally with output, forming a straight line. • **Slope equals market price** — the constant slope of this straight line equals the fixed market price, which also equals Marginal Revenue and Average Revenue. • 💡 Wrong-option analysis: [Option A] A horizontal line for the TR curve would mean revenue is constant regardless of output, which is incorrect; [Option B] U-shaped is the shape of Average Variable Cost and Average Total Cost curves; [Option D] Inverted U-shaped describes the TR curve for a monopoly, where TR first rises then falls as the firm lowers price to sell more.

Correct Answer: B. Zero

• **Zero** = a vertical supply curve means quantity supplied is completely fixed regardless of price, indicating perfectly inelastic supply with elasticity = 0. • **Fixed supply examples** — land in a city, rare art, or tickets for a sold-out event cannot increase supply even if price rises sharply. • 💡 Wrong-option analysis: [Option A] Infinite elasticity is shown by a horizontal supply curve, meaning suppliers will supply any amount at one price; [Option C] Unitary elasticity (= 1) means a 1% price change causes exactly a 1% change in quantity supplied; [Option D] Less than one (inelastic but not zero) means quantity supplied responds some but less proportionately to price changes.

Correct Answer: A. Unit Cost and Cumulative Output

• **Unit Cost and Cumulative Output** = the Learning Curve shows that as cumulative production experience grows, average cost per unit systematically decreases. • **Experience effect** — workers become more proficient, processes improve, and waste is reduced with accumulated production, lowering per-unit cost over time. • 💡 Wrong-option analysis: [Option B] Price and Quantity relationship is shown by Demand or Supply curves; [Option C] Wages and Hours relationship is part of labour economics, not the Learning Curve; [Option D] Inflation and Growth relationship is related to the Phillips Curve, not the Learning Curve.