Q.Write a note on externalities.
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🔒 Start your 14-day free trial to unlock the full solution →Concept understanding — Public Goods Provision
You are walking home with a friend who bought a pack of biscuits. She opens it and starts eating. You can smell the biscuits from a metre away. Can she stop you from enjoying that smell? No. And if she eats one biscuit, is there less biscuit left for her? Yes. That simple difference is the entire foundation of public goods.
The Two Key Properties
Economists classify goods based on two questions:
- Rivalry: If I consume one unit, does that leave less for you? (A biscuit is rival – once eaten, it's gone. A song on the radio is non-rival – my listening doesn't reduce it for you.)
- Excludability: Can the seller prevent you from consuming it if you don't pay? (A cinema ticket is excludable – no ticket, no entry. A lighthouse beam is non-excludable – you can't stop a ship from seeing it.)
A public good is a good that is both non-rival and non-excludable.
Public Good = Non-Rival + Non-Excludable
The classic textbook example is national defence. If the army protects the country from invasion, it protects everyone within the borders. My being protected does not reduce the protection you get (non-rival). And you cannot be excluded from that protection even if you refuse to pay taxes (non-excludable).
Another example is clean air. Everyone breathes the same air. One person breathing doesn't use it up, and you can't stop someone from breathing.
The Problem: The Free Rider
Here is where the trouble begins. Because a public good is non-excludable, a rational person thinks: "Why should I pay for it? I will get the benefit anyway, whether I pay or not."
This is the free rider problem. If everyone thinks this way, no one pays. The good is either not provided at all, or is provided at a much lower level than society actually wants.
Think of a streetlight in your colony. If the residents are asked to voluntarily contribute money to install it, many will say, "I can see from my window just fine without paying. Let others pay." If everyone does that, the streetlight never gets installed, even though everyone would be better off with it.
A common mistake is to think "public good" means "provided by the government." That is not the definition. A public good is defined by its economic properties (non-rival, non-excludable). The government often provides it (like defence or streetlights) precisely because the free rider problem makes private provision impossible.
The Solution: Government Provision
Because the market fails to provide public goods efficiently, the government steps in. It uses its power of taxation to force everyone to contribute. The tax is the "price" you pay for the public good, whether you wanted it or not.
The government then decides how much of the public good to provide. This is a difficult decision because there is no market price to signal what people want. The government must use tools like cost-benefit analysis or voting to decide the optimal level.
Private Goods (a biscuit, a phone) are rival and excludable. Markets handle these well.
Common Resources (a public park, a fishing ground) are rival but non-excludable. These face the "tragedy of the commons" – overuse. …
Some activities affect people who are not part of the transaction, imposing costs or benefits for which no payment changes hands.
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Externality = a benefit or harm to a third party for which no payment is made; can be positive or negative.
An externality (or spillover effect) arises when the production or consumption activity of one person or firm affects other people who are not part of the transaction, without any compensation being paid or received. Because these effects are outside the market, they are not reflected in market prices.
- Negative externality — imposes a cost on others. Example: a factory that discharges smoke or effluent harms the health and environment of nearby residents, who are not compensated. Here private cost is less than social cost, so the good is over-produced.
- Positive externality — confers a benefit on others. Example: a person who maintains a beautiful garden or gets vaccinated benefits neighbours, who pay nothing for it. Here social benefit exceeds private benefit, so the activity is under-produced. …
Showing the 12 most recent of 16 on this concept.
- CBSE 2026Set 58/3/11 markMCQQ.“Consumption of a good by a person does not reduce the amount available for consumption by others. Consumers consuming such goods are known as free-riders.” Identify the type of goods indicated in the above text. Options : (A) Public goods (B) Private goods (C) Joint venture goods (D) Self-consumption goods
›Reveal solutionSolution
The text describes non-rival goods where consumption by one person doesn't diminish availability for others, and the free-rider problem arises because exclusion is difficult. These are public goods.
The passage gives you two critical clues about the nature of the good. First, consumption by one person does not reduce the amount available for others—this is the defining feature of non-rivalry. Think of national defense: my protection by the army doesn't leave less protection for you. Second, the mention of "free-riders" signals that people can consume the good without paying for it, which happens when a good is non-excludable—you cannot prevent anyone from enjoying it once it is provided.
Public goods are characterized precisely by these two properties: non-rivalry and non-excludability. Street lighting is a classic example. Once installed, my use of the light to walk safely at night doesn't reduce the light available to you, and the municipality cannot realistically exclude non-payers from benefiting. Because exclusion is impossible, rational individuals have an incentive to free-ride—to enjoy the benefits without contributing to the cost—which is why markets typically under-provide or fail to provide public goods at all, necessitating government intervention.
Private goods, by contrast, are both rival (your consumption of an apple means I cannot consume that same apple) and excludable (the shopkeeper can refuse to give you the apple unless you pay). Joint venture goods and self-consumption goods are not standard economic classifications in the theory of public goods. …
- CBSE 2025Set 58/4/11 markMCQQ.Read the following statements carefully : Statement 1 : Public goods are those goods for which the payments are made by all the entities in the country. Statement 2 : Private goods are those goods which are provided by the government of a country at subsidised rates. In the light of the given statements, choose the correct option from the following : (A) Statement 1 is true and Statement 2 is false. (B) Statement 1 is false and Statement 2 is true. (C) Both Statements 1 and 2 are true. (D) Both Statements 1 and 2 are false.
›Reveal solutionSolution
Both statements are incorrect; public goods are defined by non-rivalry and non-excludability, typically funded by taxes, while private goods are rivalrous and excludable, usually provided by private entities.
In economics, goods are broadly classified based on two fundamental characteristics: rivalry and excludability. Understanding these distinctions is crucial for comprehending how different goods are provided and consumed within an economy, and why governments often intervene in the provision of certain types of goods.
Public Goods
Public goods are characterized by two key features:
- Non-rivalry: One person's consumption of the good does not diminish another person's ability to consume it. For example, if one person enjoys the benefits of national defense, it does not reduce the amount of national defense available to others. Similarly, many people can enjoy a street light without reducing its illumination for anyone else.
- Non-excludability: It is either impossible or prohibitively costly to prevent individuals from consuming the good, even if they do not pay for it. Once a public good is provided, it is difficult to exclude anyone from benefiting from it. For instance, it is hard to prevent any citizen from benefiting from national defense or street lighting, regardless of whether they have directly paid for it.
Due to these characteristics, public goods often face the "free-rider problem." Individuals can benefit from the good without contributing to its cost, leading to under-provision if left to the private market. This is why public goods like national defense, street lighting, and public parks are typically provided by the government and funded through general taxation, rather than direct payments for consumption by individual users.
NoteThe payment for public goods comes from general taxes collected from citizens and businesses, not from direct payments made by all entities specifically for the consumption of that particular good. The benefit is available to all, irrespective of their direct payment for it.
Private Goods
In contrast, private goods possess the opposite characteristics:
- Rivalry: One person's consumption of the good prevents another person from consuming the same unit of that good. For example, if you eat a slice of pizza, no one else can eat that exact slice. If you wear a particular shirt, no one else can wear it at the same time.
- Excludability: It is possible to prevent individuals from consuming the good if they do not pay for it. A seller can easily prevent someone from eating a slice of pizza or wearing a shirt if they haven't paid the price.
Private goods are typically provided by private firms in competitive markets. Consumers pay a price for these goods, and those who do not pay are excluded from consuming them. The market mechanism works efficiently for private goods because producers can charge a price and exclude non-payers, ensuring that resources are allocated based on demand and willingness to pay.
ImportantThe definition of a private good is based on its inherent characteristics of rivalry and excludability, not on who provides it or at what price. While governments might sometimes provide certain private goods (like healthcare or education) and subsidize them, this is a policy choice, not a defining feature of a private good itself.
Now, let's evaluate the given statements:
Statement 1: Public goods are those goods for which the payments are made by all the entities in the country. …
- CBSE 2025Set 58/5/11 markMCQQ.Identify, which of the following does not represent a public good. (Choose the correct option) (A) Free vaccines provided by the government (B) Defence services provided by the military (C) Purchase of railway ticket by an individual (D) Street light installed by a city municipality
›Reveal solutionSolution
Public goods are characterized by non-rivalry and non-excludability. A railway ticket is a private good because its consumption is rivalrous (one person's use prevents another's) and excludable (non-payers can be prevented from using it).
In economics, goods and services are often classified based on two key characteristics: rivalry and excludability. Understanding these concepts is crucial for identifying what constitutes a public good.
- Rivalry: A good is rivalrous if one person's consumption of it prevents or diminishes another person's ability to consume the same unit of the good. For example, if you eat an apple, no one else can eat that same apple.
- Excludability: A good is excludable if it is possible to prevent people from consuming it if they do not pay for it. For example, a cinema can exclude you from watching a movie if you don't buy a ticket.
A public good is a good that is both non-rivalrous and non-excludable.
Because public goods are non-excludable, it is difficult to charge individuals for their use, leading to the "free-rider problem" where people can benefit without paying. Because they are non-rivalrous, the marginal cost of an additional person consuming the good is zero. These characteristics often mean that private markets under-provide public goods, necessitating government provision.
Let's analyze each option:
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(A) Free vaccines provided by the government: While an individual vaccine dose is rivalrous (one person uses one dose) and excludable (you can be denied a dose), the public health benefit of widespread vaccination (e.g., herd immunity, reduced disease transmission) is largely non-rivalrous and non-excludable. When the government provides free vaccines, it aims to achieve these broader public health outcomes, which function as public goods. The societal benefit of a healthier population is a classic example of a positive externality that takes on public good characteristics.
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(B) Defence services provided by the military: This is a quintessential example of a pure public good.
- Non-rivalrous: The protection provided by national defense to one citizen does not reduce the protection available to any other citizen.
- Non-excludable: It is practically impossible to exclude any citizen within the country's borders from benefiting from national defense, regardless of whether they pay taxes for it. …
- CBSE 2025Set ANNUAL1 markMCQQ.Example of public goods is - (A) National security (B) Roads (C) Government administration (D) All of the above
›Reveal solutionSolution
National security, roads and government administration are all public goods, so (D) is correct.
In the RBSE/CBSE Class-12 government-budget chapter, public goods have two defining features:
- Non-rivalry — one person's consumption does not reduce the amount available to others.
- Non-excludability — no individual can be excluded from enjoying the good. …
- CBSE 2025Set ANNUAL1 markMCQQ.Identify which of the following steps was taken by the government of India to improve the efficiency of public sector undertakings? (A) Financial autonomy (B) Operational autonomy (C) Managerial autonomy (D) All of these
›Reveal solutionSolution
To improve the efficiency of public sector undertakings (PSUs), the government granted them greater autonomy in decision-making across financial, operational and managerial domains together -- not just one dimension in isolation -- so the comprehensive answer is All of these.
As part of the economic reforms, well-performing central public sector enterprises were designated as Maharatnas, Navratnas and Miniratnas. This status conferred enhanced autonomy: financial autonomy (greater freedom to raise capital and make investment decisions up to a higher limit without seeking government approval each time), operational autonomy (freedom to take day-to-day business decisions, form joint ventures, enter new markets) and managerial autonomy (freedo …
- CBSE 2025Set ANNUAL1 markQ.Why is it necessary to become a member of World Trade Organisation (WTO)?
›Reveal solutionSolution
Membership of the World Trade Organisation gives a country assured and fair access to other countries' markets, a say in global trade rule-making, and legal protection through WTO's dispute-settlement system -- benefits a country would forgo by staying outside.
The WTO is the principal international body governing rules of trade between nations, succeeding GATT. By joining the WTO, a member country gains Most-Favoured-Nation (MFN) access to the markets of all other member countries, meaning it cannot be arbitrarily discriminated against in trade -- all members must treat it at least as well as they treat their most favoured trading partner. Membership also provides a rule-based, binding dispute-settlement mechanism to resolve trade conflicts, instead of being at the mercy of unilateral actions by more powerful trading partners. Furthermore, since major global trade rules (on tariffs, subsidies, intellectual property, services, etc.) are negotiated among WTO members, staying outside would mean having no voice in decisions that directly affect the country's tr …
- CBSE 2025Set ANNUAL1 markMCQQ.What does TRAI stand for?(a) Telecom Regulation Authority of India(b) Telecom Regulating Authority of India(c) Telecom Regulatory Authority of India(d) Telecom Regulated Authority of India
›Reveal solutionSolution
TRAI stands for the Telecom Regulatory Authority of India — the regulator set up as part of India's economic reforms once the telecom sector was opened to private and foreign competition.
Before the economic reforms of the 1990s, telecommunications in India was run almost entirely as a government department/monopoly. As part of liberalisation and privatisation, the government opened the telecom sector to private operators, which created a need for an independent body to regulate tariffs, ensure fair competition between government and private players, and protect consumer interests — rather than leaving these decisions to the government department that was itself also a market participant.
This led to the establishment of the Telecom Regulatory Authority of India (TRAI) in 1997, under the TRAI Act, 1997. TRAI's core responsibilities include regulating tariffs for telecom services, laying down interconnection requirements between operators, ensuring quality of service standards, and recommending terms for new licences — functions that keep the now-competitive, privatised telecom market functioning fairly for consumers.
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- CBSE 2024Set MARCH1 markQ.Who are 'Free riders'?
›Reveal solutionSolution
Free riders are people who enjoy the benefit of a public good without paying for it.
Public goods (like national defence, street lighting or a public park) are non-rival and non-excludable — once provided, no one can be prevented from using them, and one person's use does not reduce another's. This creates the free-rider problem: individuals have an incentive to consume the good while not revealing their true preference or not paying for it, since they cannot be excluded anyway. Such consumers, who benefit without bearing the cost, …
- CBSE 2024Set ANNUAL1 markMCQQ.By implementing measures like cash transfers to senior citizens and widows, the government is trying to achieve the objective of(a) reallocation of resources(b) redistribution of income(c) regional equality(d) All of the above
›Reveal solutionSolution
Cash transfers to vulnerable groups serve the budget's redistribution-of-income objective.
The government budget pursues allocation (directing resources towards goods the market under-provides, e.g. subsidising primary education, taxing harmful goods), redistribution (using progressive taxation and transfer payments — pensions, scholarships, subsidies — to reduce the gap between the rich and the poor) and stabilisation (using taxation/spending to smooth business-cycle fluctuations and control inflation/unemployment). A direct cash transfer to senior citizens and widows, who typically have little or no independent income, is a transfer payment that shifts purchasing power towards those with lower incom …
- CBSE 2024Set ANNUAL1 markQ.What is government budget?
›Reveal solutionSolution
The government budget is the annual plan of the government's expected income and spending.
It is presented to Parliament under Article 112 of the Constitution and is split into a revenue budget (revenue receipts such as taxes, and revenue expenditure such as salaries and interest payments, neither of which creates or reduces assets/liabilities) and a capital budget (capital receipts such as borrowings and disinvestment, and capital expenditure such as building infrastructure or acquiring assets, which do affect the government's assets/liabilities). Besides simply listing numbers, the budget is also the governme …
- CBSE 2023Set MARCH1 markMCQQ.A good that is non-rival and non-excludable is(a) Public goods(b) Inferior good(c) Private goods(d) Capital goods
›Reveal solutionSolution
The two properties named — non-rival and non-excludable — are the exact definition of a public good in Kerala Plus Two (DHSE) economics.
Why:
- Non-rival in consumption: one person consuming the good does not reduce the amount available to others (e.g. watching a public fireworks display).
- Non-excludable: it is not possible (or not practical) to prevent anyone from enjoying the good once it is provided, so people cannot be charged individually and free-riding arises. …
- CBSE 2023Set ANNUAL1 markQ.Fill in the blank: Roads and government administration are called _______ goods.
›Reveal solutionSolution
Roads and government administration are public goods, so the blank is 'public'.
Public goods have two features: they are non-rival (one person's use does not reduce another's) and non-excludable (people cannot be kept from benefiting, so no one will pay voluntarily). Roads and government administratio …
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