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IB Economics HL study materials
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IB Economics HL practice questions

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Question 1Introduction to Economics (scarcity, choice, opportunity cost, PPC, market models)

A student can spend the afternoon either working a shift that pays 40 units of currency or revising for an examination. The student chooses to revise. In the language of economics, what is the opportunity cost of revising?

  1. The 40 units of currency forgone by not working the shift Correct answer.
  2. Zero, because revising produces no money income
  3. The examination grade the student expects to achieve
  4. The total value of the revision plus the 40 units of currency

Explanation

Opportunity cost is the value of the next best alternative that must be given up when a choice is made. Since the shift is the alternative forgone, its earnings of 40 units measure the opportunity cost of revising. The benefit actually obtained from revising is not part of the cost.

Question 2Introduction to Economics (scarcity, choice, opportunity cost, PPC, market models)

Which statement best describes the economic problem of scarcity as used in IB Economics?

  1. Some households are poor while others are wealthy
  2. Governments choose to ration goods during a war
  3. Certain goods are temporarily out of stock in shops
  4. Resources are limited relative to the unlimited wants of society Correct answer.

Explanation

Scarcity is a universal condition: factors of production are finite while human wants are effectively unlimited, so choices must be made. It applies to every economy, however rich, and is not the same as poverty or a temporary shortage.

Question 3Introduction to Economics (scarcity, choice, opportunity cost, PPC, market models)

An economy produces only two goods, X and Y. It currently produces 200 units of X and 50 units of Y. Producing an extra 20 units of X would require giving up 10 units of Y. What does this information illustrate?

  1. That the economy has achieved allocative efficiency in both markets
  2. That the opportunity cost of 1 unit of X is 0.5 units of Y Correct answer.
  3. That the economy is operating inside its production possibility curve
  4. That producing more X requires no sacrifice of Y

Explanation

The opportunity cost of one more unit of X equals the Y forgone divided by the X gained, here 10 divided by 20, which is 0.5 units of Y. Moving along a production possibility curve always involves such a trade-off.

Question 4Introduction to Economics (scarcity, choice, opportunity cost, PPC, market models)

A production possibility curve is drawn as a straight downward-sloping line rather than a curve bowed outward from the origin. What does the straight line imply?

  1. Opportunity cost rises as more of either good is produced
  2. Resources are completely unspecialised and cannot be reallocated
  3. Opportunity cost is constant as output switches between the two goods Correct answer.
  4. The economy cannot attain any point on the line

Explanation

The slope of a production possibility curve measures the opportunity cost of the good on the horizontal axis. A constant slope therefore means a constant opportunity cost, which arises when the factors of production are equally suited to producing either good.

Question 5Introduction to Economics (scarcity, choice, opportunity cost, PPC, market models)

A technological improvement raises labour productivity in the consumer goods sector only. On a production possibility curve with consumer goods on the horizontal axis and capital goods on the vertical axis, what happens?

  1. The curve shifts outward along both axes by the same proportion
  2. The vertical intercept rises while the horizontal intercept is unchanged
  3. The economy moves from a point on the curve to a point inside it
  4. The horizontal intercept moves outward while the vertical intercept stays put Correct answer.

Explanation

Productivity gains confined to consumer goods raise the maximum output of consumer goods, so the horizontal intercept shifts outward. The maximum output of capital goods is unchanged, so the vertical intercept stays where it was and the curve rotates outward.

Question 6Introduction to Economics (scarcity, choice, opportunity cost, PPC, market models)

In a market for a normal good, consumer incomes rise and at the same time the cost of a key raw material falls. What is the predictable effect on the equilibrium price and quantity?

  1. Price definitely rises; quantity definitely rises
  2. Price definitely rises; quantity change is indeterminate
  3. Price definitely falls; quantity change is indeterminate
  4. Price change is indeterminate; quantity definitely rises Correct answer.

Explanation

Higher incomes shift demand rightward, raising both price and quantity, while lower raw material costs shift supply rightward, lowering price and raising quantity. Both changes push quantity up, but they push price in opposite directions, so the price effect cannot be determined without knowing the size of each shift.

Question 7Introduction to Economics (scarcity, choice, opportunity cost, PPC, market models)

A government sets a price ceiling below the free-market equilibrium price for a good. Which outcome is expected in that market?

  1. A surplus, because quantity supplied exceeds quantity demanded
  2. Excess demand, because quantity demanded exceeds quantity supplied Correct answer.
  3. A rise in producer surplus as more units are sold
  4. No change in quantity traded, because the ceiling is not binding

Explanation

A binding price ceiling is set below equilibrium, so at that price quantity demanded exceeds quantity supplied and excess demand appears. The quantity actually traded falls to the amount suppliers are willing to sell, which can create queues or black markets.

Question 8Introduction to Economics (scarcity, choice, opportunity cost, PPC, market models)

Which feature distinguishes an oligopolistic market from a monopolistically competitive market?

  1. Oligopolies always earn normal profit in the long run while monopolistic competitors earn supernormal profit
  2. Oligopolies face no barriers to entry while monopolistic competitors face high barriers
  3. Oligopolies have few firms whose decisions are interdependent, while monopolistic competitors have many firms acting independently Correct answer.
  4. Oligopolies sell differentiated products while monopolistic competitors sell homogeneous products

Explanation

The defining feature of oligopoly is a small number of large firms, so each firm must consider rivals' reactions when setting price or output, which is strategic interdependence. Monopolistic competition has many firms, each too small to affect the others, and entry is relatively free.

Question 9Introduction to Economics (scarcity, choice, opportunity cost, PPC, market models)

A firm in a perfectly competitive market is currently producing where marginal cost equals marginal revenue and marginal cost is rising. Its price equals average total cost at that output. What can be concluded?

  1. The firm is making a loss and should shut down immediately
  2. The firm is earning supernormal profit and should expand output
  3. The firm is allocatively inefficient because price exceeds marginal cost
  4. The firm is making normal profit and is in long-run equilibrium Correct answer.

Explanation

Profit is maximised where marginal cost equals marginal revenue and marginal cost is rising. If price, which equals marginal revenue in perfect competition, also equals average total cost, the firm covers all costs including the opportunity cost of capital, so it earns normal profit, the long-run outcome under free entry.

Question 10Introduction to Economics (scarcity, choice, opportunity cost, PPC, market models)

A monopolist faces a downward-sloping demand curve and maximises profit at an output where marginal cost is below price. Which statement correctly describes the welfare implication?

  1. Total surplus is maximised because the monopolist restricts output to raise price
  2. Deadweight loss arises because output is below the level where price equals marginal cost Correct answer.
  3. Consumer surplus is maximised because the monopolist charges a single price
  4. The monopolist is allocatively efficient because marginal cost equals marginal revenue

Explanation

Allocative efficiency requires price to equal marginal cost so that the marginal value to consumers matches the marginal cost of production. A profit-maximising monopolist stops where marginal revenue equals marginal cost, and since price exceeds marginal revenue, price exceeds marginal cost and output is too low, creating deadweight loss.

Question 11Microeconomics: demand and supply, elasticity, government intervention, market failure

A price ceiling set below the equilibrium price will, in a competitive market, lead to which outcome?

  1. A shortage because quantity demanded exceeds quantity supplied Correct answer.
  2. A surplus because quantity supplied exceeds quantity demanded
  3. No change in market outcomes because price ceilings are non-binding
  4. An increase in producer surplus as firms sell at a controlled price

Explanation

A binding price ceiling sits below equilibrium, so at that lower price quantity demanded rises while quantity supplied falls. The gap between them is a shortage, and the quantity actually traded is limited to the smaller supplied amount.

Question 12Microeconomics: demand and supply, elasticity, government intervention, market failure

The price elasticity of demand for a good is 0.4. A 10% rise in price will cause quantity demanded to change by approximately:

  1. 4% fall Correct answer.
  2. 4% rise
  3. 25% fall
  4. 0.4% fall

Explanation

Elasticity of demand equals the percentage change in quantity demanded divided by the percentage change in price. Multiplying 0.4 by 10% gives a 4% change, and the direction is a fall because demand curves slope downward.

Question 13Microeconomics: demand and supply, elasticity, government intervention, market failure

Which characteristic of a good tends to make its price elasticity of demand higher?

  1. The presence of many close substitutes Correct answer.
  2. The good being a strict necessity
  3. A very short time period under consideration
  4. The good being a small share of consumer income

Explanation

Consumers can switch to alternatives when close substitutes exist, so a price rise causes a large fall in quantity demanded. Substitutability is one of the main determinants of elastic demand.

Question 14Microeconomics: demand and supply, elasticity, government intervention, market failure

A negative externality of production exists when:

  1. Marginal private cost exceeds marginal social cost
  2. Marginal social cost exceeds marginal private cost Correct answer.
  3. Marginal private benefit exceeds marginal social benefit
  4. Marginal social benefit exceeds marginal private benefit

Explanation

A production externality means third parties bear costs not reflected in the producer's private costs. Marginal social cost therefore exceeds marginal private cost, and the free market overproduces relative to the social optimum.

Question 15Microeconomics: demand and supply, elasticity, government intervention, market failure

A good is said to be a public good when it exhibits:

  1. Non-rivalry and excludability
  2. Rivalry and non-excludability
  3. Rivalry and excludability
  4. Non-rivalry and non-excludability Correct answer.

Explanation

Public goods have two defining features: one person's use does not reduce availability to others, and producers cannot prevent non-payers from consuming. These lead to the free-rider problem and market underprovision.

Question 16Microeconomics: demand and supply, elasticity, government intervention, market failure

Which of the following shifts the supply curve for coffee to the right?

  1. An increase in consumer incomes
  2. A fall in the wage paid to coffee pickers Correct answer.
  3. A successful advertising campaign for tea
  4. A rise in the market price of coffee

Explanation

A fall in input costs reduces the cost of production at every quantity, so producers are willing to supply more at each price. This is a rightward shift of the supply curve.

Question 17Microeconomics: demand and supply, elasticity, government intervention, market failure

If the demand for a product is price inelastic, a firm raising its price will experience:

  1. A rise in total revenue Correct answer.
  2. A fall in quantity demanded proportionally larger than the price rise
  3. Total revenue unchanged
  4. A fall in total revenue

Explanation

With inelastic demand, quantity demanded falls proportionally less than the price rises. The price effect dominates the quantity effect, so total revenue increases.

Question 18Microeconomics: demand and supply, elasticity, government intervention, market failure

The socially optimal quantity of a good with a negative production externality is found where:

  1. Marginal private cost equals marginal social cost
  2. Marginal social cost equals marginal social benefit Correct answer.
  3. Marginal private cost equals marginal private benefit
  4. Marginal social benefit is at its maximum

Explanation

The social optimum accounts for all costs and benefits, so it occurs where marginal social cost intersects marginal social benefit. The free market instead equates private cost and private benefit, producing too much.

Question 19Microeconomics: demand and supply, elasticity, government intervention, market failure

A government imposes a specific (per-unit) tax on a good with inelastic demand and elastic supply. Who bears the larger share of the tax burden?

  1. Consumers, because demand is relatively inelastic Correct answer.
  2. Neither party, because the tax falls only on the government
  3. Producers, because supply is relatively elastic
  4. The burden is shared equally regardless of elasticities

Explanation

The tax burden falls more heavily on the side of the market that is less able to change behaviour. Inelastic demand means consumers cannot easily avoid the tax, so they absorb most of it through a higher price.

Question 20Microeconomics: demand and supply, elasticity, government intervention, market failure

A firm faces a price elasticity of supply of 1.5. If price rises by 8%, quantity supplied rises by approximately:

  1. 8%
  2. 12% Correct answer.
  3. 1.5%
  4. 5.3%

Explanation

Elasticity of supply equals the percentage change in quantity supplied divided by the percentage change in price. Multiplying 1.5 by 8% gives 12%.

Question 21Microeconomics: demand and supply, elasticity, government intervention, market failure

A consumer's demand curve for a good is downward sloping. Which statement best explains the income effect of a price fall?

  1. Real income rises, allowing the consumer to buy more of the good Correct answer.
  2. The good becomes relatively cheaper than substitutes, so consumers switch toward it
  3. Consumers expect future prices to rise and buy more now
  4. Producers increase output because the price has fallen

Explanation

A price fall raises the consumer's real purchasing power, which is the income effect. The substitution effect, by contrast, concerns the good becoming relatively cheaper than alternatives.

Question 22Microeconomics: demand and supply, elasticity, government intervention, market failure

A market has a positive externality of consumption. Compared with the social optimum, the free-market equilibrium will show:

  1. The same price and quantity, since externalities affect only producers
  2. A lower price and a larger quantity traded
  3. A lower price and a smaller quantity traded Correct answer.
  4. A higher price and a larger quantity traded

Explanation

Consumers ignore the external benefits, so marginal social benefit exceeds marginal private benefit and demand is understated. The market therefore trades less than the socially optimal quantity, at a lower price.

Question 23Microeconomics: demand and supply, elasticity, government intervention, market failure

A price floor set above equilibrium in the labour market, such as a minimum wage, is most likely to cause:

  1. A shortage of labour as demand exceeds supply
  2. Unemployment as quantity of labour supplied exceeds quantity demanded Correct answer.
  3. A fall in wages below the equilibrium level
  4. No effect because wages are always at equilibrium

Explanation

A binding minimum wage above equilibrium raises the price of labour, increasing the quantity of labour supplied and reducing the quantity demanded. The excess supply of labour appears as unemployment.

Question 24Microeconomics: demand and supply, elasticity, government intervention, market failure

Which policy is most appropriate to correct a negative externality of production?

  1. A public awareness campaign encouraging more consumption
  2. A price ceiling below equilibrium
  3. A subsidy to increase output
  4. A Pigouvian tax equal to the marginal external cost Correct answer.

Explanation

A Pigouvian tax set equal to the marginal external cost makes producers internalise the external cost. This raises private cost toward social cost and reduces output toward the social optimum.

Question 25Microeconomics: demand and supply, elasticity, government intervention, market failure

The cross-price elasticity of demand between two goods is negative. This indicates that the goods are:

  1. Unrelated in consumption
  2. Complements Correct answer.
  3. Substitutes
  4. Inferior goods

Explanation

A negative cross-price elasticity means a rise in the price of one good reduces demand for the other. This happens when the goods are consumed together, so they are complements.

Question 26Microeconomics: demand and supply, elasticity, government intervention, market failure

Income elasticity of demand for a good is -0.7. Which conclusion follows?

  1. The good is a necessity with inelastic demand
  2. The good is inferior and demand falls as income rises Correct answer.
  3. The good is a complement to another product
  4. The good is a luxury and demand rises faster than income

Explanation

A negative income elasticity means demand moves opposite to income, which defines an inferior good. As incomes rise, consumers switch away and quantity demanded falls.

Question 27Microeconomics: demand and supply, elasticity, government intervention, market failure

A government grants a subsidy to producers of a good with a positive externality of consumption. The likely effect is:

  1. Demand shifts left because consumers pay less
  2. The externality becomes a negative externality of production
  3. Supply shifts left, raising price and reducing quantity
  4. Supply shifts right, lowering price and raising quantity toward the social optimum Correct answer.

Explanation

A subsidy lowers producers' costs, shifting supply right and reducing the market price. The lower price encourages consumption, moving output closer to the socially optimal level.

Question 28Microeconomics: demand and supply, elasticity, government intervention, market failure

Which situation best illustrates the free-rider problem?

  1. A firm lowers its price to attract customers from rivals
  2. A monopolist restricts output to raise price
  3. People benefit from a national defence system without paying for it directly Correct answer.
  4. Consumers buy less of a good as its price rises

Explanation

National defence is non-excludable, so individuals cannot be prevented from enjoying it without paying. Each person has an incentive to free-ride, and voluntary provision would be below the efficient level.

Question 29Microeconomics: demand and supply, elasticity, government intervention, market failure

A tax is imposed on a good with perfectly inelastic demand. The burden of the tax falls:

  1. Equally on consumers and producers
  2. On the government, which collects the revenue
  3. Entirely on consumers, who pay the full tax through a higher price Correct answer.
  4. Entirely on producers, who absorb the full tax

Explanation

With perfectly inelastic demand, quantity demanded does not change at all, so producers can pass the entire tax forward. The market price rises by the full amount of the tax.

Question 30Microeconomics: demand and supply, elasticity, government intervention, market failure

A good is rival in consumption but non-excludable. This describes:

  1. A pure public good
  2. A private good
  3. A club good
  4. A common resource Correct answer.

Explanation

Common resources are rival because one person's use reduces availability, but non-excludable because access cannot be restricted. They are prone to overuse and depletion, the tragedy of the commons.

Question 31Microeconomics: demand and supply, elasticity, government intervention, market failure

A firm faces a linear downward-sloping demand curve. At the midpoint of the curve, price elasticity of demand is:

  1. Unit elastic, so total revenue is maximised Correct answer.
  2. Zero because the curve is linear
  3. Perfectly inelastic, so revenue is maximised
  4. Perfectly elastic, so revenue is zero

Explanation

Along a linear demand curve elasticity varies, being elastic at high prices, unit elastic at the midpoint and inelastic at low prices. Total revenue reaches its maximum where elasticity equals one.

Question 32Microeconomics: demand and supply, elasticity, government intervention, market failure

The free-market quantity of a good with a negative production externality exceeds the social optimum. Which statement explains the welfare loss?

  1. For all units, marginal private benefit exceeds marginal social cost
  2. Consumer surplus is zero at the free-market equilibrium
  3. For units beyond the social optimum, marginal social cost exceeds marginal social benefit Correct answer.
  4. Producer surplus is maximised at the social optimum

Explanation

Beyond the social optimum, each extra unit costs society more than it benefits society, so producing it destroys welfare. The deadweight loss equals the sum of these excess costs over the overproduced range.

Question 33Microeconomics: demand and supply, elasticity, government intervention, market failure

A government wants to reduce consumption of a demerit good with inelastic demand. Which combination is most likely to succeed in reducing quantity consumed?

  1. An indirect tax combined with regulation and information provision Correct answer.
  2. A per-unit subsidy alone
  3. A subsidy to producers combined with a price ceiling
  4. A price floor combined with increased advertising

Explanation

Because demand is inelastic, a tax alone reduces quantity only modestly, though it raises revenue. Combining the tax with regulation and education attacks consumption through several channels and is more effective.

Question 34Microeconomics: demand and supply, elasticity, government intervention, market failure

A price ceiling is imposed on a good with perfectly inelastic supply. Which outcome follows?

  1. A surplus emerges because supply exceeds demand
  2. Quantity traded falls sharply because supply cannot adjust
  3. Quantity traded is unchanged, but a shortage may appear as demand rises at the lower price Correct answer.
  4. The market clears at a higher price than before

Explanation

With perfectly inelastic supply, the quantity supplied is fixed regardless of price, so the ceiling cannot reduce the amount traded. However, at the lower price quantity demanded rises, creating excess demand.

Question 35Microeconomics: demand and supply, elasticity, government intervention, market failure

Two goods have a cross-price elasticity of +2.0. If the price of good A rises by 5%, what happens to the demand for good B, and why?

  1. It rises by 2.5% because the goods are complements
  2. It rises by 10% because the goods are substitutes Correct answer.
  3. It is unchanged because cross-price elasticity applies only to supply
  4. It falls by 10% because the goods are complements

Explanation

A positive cross-price elasticity indicates substitutes, and multiplying 2.0 by the 5% price rise gives a 10% increase in demand for B. Consumers switch from the now more expensive A toward B.

Question 36Microeconomics: demand and supply, elasticity, government intervention, market failure

A consumer allocates a fixed budget between two goods, X and Y, and is currently consuming a combination at which MUx/Px exceeds MUy/Py. Assuming the law of diminishing marginal utility holds, what adjustment maximises total utility?

  1. Buy more of both goods, financed by borrowing, until marginal utilities fall to zero
  2. Keep the combination unchanged, since total spending already equals the budget
  3. Buy more X and less Y until the ratio of marginal utilities to prices is equalised Correct answer.
  4. Buy more Y and less X because the marginal utility of Y is currently higher per dollar

Explanation

Utility maximisation requires MUx/Px = MUy/Py, the equimarginal principle. When MUx/Px is larger, each dollar spent on X yields more utility than a dollar spent on Y, so reallocating spending toward X raises total utility until the ratios converge. Diminishing marginal utility ensures this reallocation eventually closes the gap.

Question 37Microeconomics: demand and supply, elasticity, government intervention, market failure

The price elasticity of demand for a good is 0.4 and its price rises by 10%. What is the resulting change in quantity demanded, and how does total consumer expenditure respond?

  1. Quantity demanded falls by 0.4%, and total expenditure on the good is unchanged
  2. Quantity demanded falls by 40%, and total expenditure on the good rises
  3. Quantity demanded falls by 4%, and total expenditure on the good falls
  4. Quantity demanded falls by 4%, and total expenditure on the good rises Correct answer.

Explanation

Percentage change in quantity demanded equals elasticity multiplied by the percentage price change, so 0.4 × 10% = 4%. Because demand is inelastic (PED below 1), the proportional fall in quantity is smaller than the proportional rise in price, so total expenditure rises. This is the standard price–revenue relationship for inelastic demand.

Question 38Microeconomics: demand and supply, elasticity, government intervention, market failure

In a market for a good with a negative externality of production, which condition defines the allocatively efficient level of output?

  1. Marginal social cost equals zero
  2. Marginal social cost equals marginal social benefit Correct answer.
  3. Marginal private cost equals marginal private benefit
  4. Average total cost is at its minimum

Explanation

Allocative efficiency requires that the additional cost to society of the last unit equals the additional benefit to society. With a negative production externality, marginal social cost exceeds marginal private cost, so the private-market equilibrium overproduces relative to this condition. Equating MSC and MSB identifies the socially optimal quantity.

Question 39Microeconomics: demand and supply, elasticity, government intervention, market failure

A good is both non-rival in consumption and non-excludable. Which market outcome is predicted, and why?

  1. It is provided efficiently by private firms, because marginal cost is low
  2. It is underprovided or not provided at all, because private firms cannot charge free riders Correct answer.
  3. It is overprovided, because every consumer demands the full quantity
  4. It is rationed by price, because demand exceeds supply at a zero price

Explanation

These two characteristics define a pure public good. Non-excludability allows free riding, so consumers will not voluntarily pay, while non-rivalry means the efficient price is zero. Private firms therefore have no revenue incentive to supply the good, producing underprovision or non-provision.

Question 40Microeconomics: demand and supply, elasticity, government intervention, market failure

A per-unit tax is placed on a good whose demand is relatively elastic and whose supply is relatively inelastic. Compared with the pre-tax equilibrium, what is the most likely distribution of the tax burden?

  1. Consumers bear the larger share, because demand is more responsive than supply
  2. The burden is split equally, because a per-unit tax is legally imposed on one side only
  3. Producers bear the larger share, because supply is less responsive than demand Correct answer.
  4. Consumers bear the entire burden, because taxes on goods are always passed forward

Explanation

The incidence of an indirect tax depends on relative elasticities: the side of the market that is less able to adjust bears the larger share. Inelastic supply means producers cannot easily reduce output, so they absorb more of the tax through a lower net price. Elastic demand means consumers can substitute away, so the price rise is limited.

Question 41Microeconomics: demand and supply, elasticity, government intervention, market failure

A government imposes a price ceiling below the equilibrium price in a competitive market with upward-sloping supply. Which set of effects is most consistent with standard analysis?

  1. A shortage emerges, consumer surplus may rise or fall, and deadweight loss arises from lost trades Correct answer.
  2. Quantity traded rises because the lower price stimulates supply
  3. The market clears at the ceiling price with no welfare loss
  4. A surplus emerges, and producers sell more than at equilibrium

Explanation

A binding ceiling holds price below equilibrium, so quantity demanded exceeds quantity supplied, creating a shortage. The quantity actually traded falls to the supplied amount, generating deadweight loss from mutually beneficial trades that no longer occur. Consumer surplus can move either way because the gain to remaining buyers may be offset by buyers excluded from the market.

Question 42Microeconomics: demand and supply, elasticity, government intervention, market failure

The supply of a product rises sharply in response to a small price increase, while demand is unit elastic. If a subsidy per unit is paid to producers, what is the most likely outcome?

  1. The subsidy raises price to consumers and reduces the quantity traded
  2. Consumers gain most of the benefit through a price fall close to the subsidy amount Correct answer.
  3. The subsidy has no effect on price or quantity, since demand is unit elastic
  4. Producers capture most of the benefit because supply is elastic

Explanation

Subsidy benefit is distributed like tax burden but in reverse: the less elastic side captures more of the benefit. Highly elastic supply means producers quickly expand output, pushing the price down toward consumers, who therefore gain most of the subsidy. Unit-elastic demand affects total revenue but does not prevent this price effect.

Question 43Microeconomics: demand and supply, elasticity, government intervention, market failure

A firm's production process discharges pollutants into a river, imposing a cost on local residents. Which policy instrument addresses the externality most directly by making the polluter internalise the external cost?

  1. A subsidy per unit of output to help the firm modernise its equipment
  2. An increase in the firm's fixed costs through higher licence fees unrelated to output
  3. A Pigouvian tax set equal to the marginal external cost at the social optimum Correct answer.
  4. A price ceiling on the polluting product to protect consumers

Explanation

A Pigouvian tax equal to marginal external cost at the efficient output aligns marginal private cost with marginal social cost. The firm then internalises the pollution cost and reduces output to the socially optimal level. Instruments not linked to the quantity of pollution do not correct the marginal incentive to overproduce.

Question 44Microeconomics: demand and supply, elasticity, government intervention, market failure

A market has a positive externality of consumption, and the good is currently provided by the free market. Which statement correctly compares marginal social benefit, marginal private benefit and the market outcome?

  1. MSB exceeds MPB, so output is below the allocatively efficient level Correct answer.
  2. MSB exceeds MPB, so output is above the allocatively efficient level
  3. MSB equals MPB, so the market is already efficient
  4. MPB exceeds MSB, so output is above the allocatively efficient level

Explanation

A positive consumption externality means each unit consumed yields benefits to third parties, so marginal social benefit exceeds marginal private benefit. Consumers base decisions on private benefit only, so the market underconsumes relative to the level where MSB equals MSC. The efficient quantity therefore lies above the free-market quantity.

Question 45Microeconomics: demand and supply, elasticity, government intervention, market failure

A government wants to reduce the consumption of a good that generates a negative externality of consumption but has price-inelastic demand. Which measure is likely to be most effective in reducing quantity consumed?

  1. A subsidy to producers, because it reduces the price paid by consumers
  2. A small specific tax alone, because inelastic demand guarantees a large quantity response
  3. A price ceiling, because it lowers the price and discourages consumption
  4. An advertising campaign combined with a specific tax, since price signals alone are weak Correct answer.

Explanation

With inelastic demand, a tax raises price but reduces quantity only slightly, so combining it with information measures that shift demand left is more effective. Regulation and education can change preferences directly, reinforcing the price effect. This combination addresses both the price and the underlying willingness to consume.

Question 46Microeconomics: demand and supply, elasticity, government intervention, market failure

Which statement about the relationship between marginal revenue, price elasticity of demand and total revenue for a firm facing a downward-sloping demand curve is correct?

  1. Marginal revenue is positive when demand is elastic and negative when demand is inelastic Correct answer.
  2. Marginal revenue is always positive because price is always positive
  3. Total revenue is maximised where marginal revenue is at its maximum
  4. Marginal revenue equals price at every level of output on a downward-sloping demand curve

Explanation

For a downward-sloping demand curve, marginal revenue falls faster than price. When demand is elastic, a price cut raises total revenue, so marginal revenue is positive; when demand is inelastic, a price cut lowers total revenue, so marginal revenue is negative. Total revenue peaks where marginal revenue is zero and elasticity equals one.

Question 47Microeconomics: demand and supply, elasticity, government intervention, market failure

A government sets a minimum price for an agricultural product above the equilibrium price and simultaneously guarantees to buy any surplus at that price. Which outcome is most consistent with economic analysis?

  1. Producer revenue falls unambiguously because quantity demanded declines
  2. A surplus is produced and the government bears a cost, while consumers pay higher prices and some welfare is lost Correct answer.
  3. A shortage arises and the government must ration the product among consumers
  4. The market clears at the minimum price with no need for government purchases

Explanation

A minimum price above equilibrium creates excess supply because quantity supplied exceeds quantity demanded at that price. If the government buys the surplus, it incurs budgetary cost and may create storage or disposal problems, while consumers pay more and deadweight loss arises. Producer revenue may rise or fall depending on elasticity, so it is not unambiguously lower.

Question 48Microeconomics: demand and supply, elasticity, government intervention, market failure

Two markets each have a negative production externality of identical size per unit, but market A has elastic demand and market B has inelastic demand. If an identical Pigouvian tax per unit is imposed in both, how do the resulting changes in quantity compare?

  1. Quantity falls by the same proportion in both markets
  2. Quantity falls proportionally more in market A than in market B Correct answer.
  3. Quantity falls proportionally more in market B than in market A
  4. Quantity rises in market A and falls in market B

Explanation

An identical per-unit tax raises price by the same absolute amount in both markets, but the quantity response depends on elasticity. Elastic demand means consumers are more responsive to the price rise, so the proportional fall in quantity is larger in market A. Inelastic demand implies a smaller proportional reduction, so the tax corrects less of the externality in market B.

Question 49Microeconomics: demand and supply, elasticity, government intervention, market failure

A good is rival in consumption but non-excludable, creating a common-access resource problem. Which policy response is most consistent with avoiding overuse of the resource?

  1. Encouraging entry by new users to increase competition
  2. Assigning property rights or imposing a quota to limit total extraction Correct answer.
  3. Removing all charges so that access reflects marginal social cost
  4. Subsidising extraction to lower the price for users

Explanation

Non-excludability combined with rivalry means each user ignores the cost imposed on others, leading to overuse and depletion. Assigning property rights or setting a quota creates exclusion and limits total extraction toward the efficient level. Policies that lower the cost of access or encourage entry worsen the overuse.

Question 50Microeconomics: demand and supply, elasticity, government intervention, market failure

A government introduces a tradable permit scheme for a pollutant, with permits initially allocated free to existing firms. Which statement best evaluates the efficiency and equity properties of this scheme compared with an equivalent Pigouvian tax?

  1. It eliminates the need for monitoring because firms have no incentive to exceed their permits
  2. It raises revenue equal to a Pigouvian tax and therefore has identical distributional effects
  3. It achieves the target pollution level at least cost across firms but may be regressive, since permits confer windfall gains on existing polluters Correct answer.
  4. It guarantees a fixed permit price but leaves the total quantity of pollution uncertain

Explanation

Tradable permits fix the quantity of pollution and allow firms with low abatement costs to sell permits to firms with high abatement costs, achieving the target at minimum total cost. Free allocation, however, gives existing polluters valuable assets and can be regressive, unlike a tax that raises public revenue. The two instruments differ in whether price or quantity is fixed and in their revenue effects.