Take a slow breath before you start. For most of you this is the very first Economics chapter you have ever opened, and the word “Microeconomics” sounds far heavier than it actually is. So let me tell you the good news right at the beginning: this chapter has almost no formulas, no long derivations and no frightening vocabulary. It is really one small story told in four or five different ways, and the story is this — we all want more than we can possibly have, so we are forced to choose, and every choice quietly costs us something else. That is the whole chapter. If that one sentence settles into your head, everything below will feel like common sense dressed up in nice terms.
Think about your own Sunday morning. You have three hours free. You could finish a web series, or go for cricket practice, or actually sit and revise Accountancy. You cannot do all three properly. Time is limited, your wishes are not. The moment you pick one, the best of the other two is gone. Congratulations — you have just done Economics. The rest of this chapter simply gives that everyday feeling a proper name, a diagram and a mark scheme.
One more reassurance. This unit carries only about 4 marks in the Class 11 paper, but do not let the small number fool you. Every single chapter that follows — demand, supply, cost, revenue, market equilibrium — stands on the ideas you are about to learn here. Students who rush this chapter end up confused in December. Students who take it slowly in April find the rest of the year surprisingly easy. Be the second kind. We will go step by step, and I will not leave you behind.
What You Will Learn
- What Is An Economy?
- The Economic Problem: Scarcity, Unlimited Wants And Choice
- The Three Central Problems Of An Economy
- Opportunity Cost: The Real Price Of Every Choice
- The Production Possibility Curve: Schedule And Diagram
- Marginal Rate Of Transformation And Why The PPC Is Concave
- Points On, Inside And Outside The Curve
- Shifts And Rotations Of The Production Possibility Curve
- Microeconomics And Macroeconomics: Meaning And Difference
- Positive Economics And Normative Economics
- Practice Worksheet With Full Answers
Your Game Plan
Do not read this chapter like a story book from top to bottom in one sitting. Work it like this instead:
- Read the first four sections in one go — economy, scarcity, central problems, opportunity cost. These are pure understanding, no numbers. Do not move on until the phrase “opportunity cost” makes you nod rather than blink.
- Then take the PPC sections slowly, with a pencil and graph paper. Copy every schedule by hand and plot the points yourself. A PPC you have drawn once with your own hand is worth ten PPCs you have only looked at.
- Practise the MRT column until it becomes automatic. Nine out of ten numerical questions from this chapter are secretly just a subtraction and a division.
- Learn the two comparison tables (micro vs macro, positive vs normative) by writing them out from memory twice. Board examiners love these as 3-markers and 4-markers.
- Finally, close the notes and attempt the worksheet at the end. Write your answer first, then open the “Show Answer” box. Peeking early feels comfortable and teaches you nothing.
What Is An Economy?
Start with something you can see. Look around your own colony or town. There is a tailor stitching, a chaiwala boiling milk, a school teaching, a truck carrying cement, a bank lending money, a family buying atta. Nobody has told each of these people what to do, yet somehow bread reaches the shop, buses reach the stop and shirts reach the showroom. That whole arrangement — people producing things, other people buying and using them, and resources being pushed around between the two — is what we call an economy.
So, in simple exam language: an economy is a system in which people carry out economic activities — production, consumption, exchange, investment and distribution — using the limited resources available to them. An economy can be as large as India or as small as a village. A useful mental picture is a very large kitchen with limited ingredients and a lot of hungry people: the ingredients are resources, the cooking is production, the eating is consumption, and the rules about who gets how much are distribution.
What exactly are these “resources”? Economists group them into four factors of production, and it is worth memorising them now because they will follow you all the way to Class 12:
- Land — everything nature gives us: soil, rivers, minerals, sunlight, forests.
- Labour — the physical and mental effort human beings put in.
- Capital — man-made things used to produce other things: machines, tools, factory sheds, trucks. Note carefully, in Economics “capital” does not mean money.
- Entrepreneurship — the person who brings the other three together, takes the risk and organises production.
Economies are usually classified into three types depending on who decides what gets produced. You do not need great detail here, but knowing the names saves you in a one-mark question.
- Market economy — decisions are taken by private producers and consumers through the price mechanism. Nobody is in charge; prices do the signalling.
- Centrally planned economy — the government (or a planning authority) decides what to produce, how and for whom.
- Mixed economy — both the market and the government play a role. India is a mixed economy.
Question. Ravi says, “My mother cooking dinner at home is not part of the economy, because she is not paid.” Is he right?
Answer. Ravi is only half right, and the reason matters. Cooking at home is certainly an economic activity in the ordinary sense — it uses resources (gas, vegetables, her labour and time) to satisfy a want (hunger). What Ravi is really pointing at is a measurement problem: because no money changes hands, such non-market household services are not counted in the national income statistics you will study in Class 12. So the activity is economic in nature, but it goes unrecorded. Remember the distinction: “not counted” is not the same as “not economic”.
Question (3 marks). Define an economy. Briefly explain any two of its main features.
Model answer.
Meaning (1 mark). An economy is a system in which the people of a region use their limited resources to carry out economic activities such as production, consumption, exchange and distribution, in order to satisfy their wants.
Feature 1 — Limited resources (1 mark). Every economy has a fixed stock of land, labour, capital and entrepreneurship at any given time. Because these resources are scarce, the economy cannot produce everything it would like to produce.
Feature 2 — Alternative uses of resources (1 mark). The same resource can be put to more than one use. A hectare of land can grow wheat or sugarcane; a worker can stitch shirts or bake bread. It is precisely this alternative-use property that forces the economy to choose, and choosing is what economics studies.
Why it works. We begin with the idea of an economy because the entire chapter is about a problem that only makes sense at the level of a whole system. An individual can borrow, beg or wait. An economy as a whole cannot — whatever it consumes, it must first produce out of the resources it actually has. That hard boundary is what creates every idea that follows.
The Economic Problem: Scarcity, Unlimited Wants And Choice
Here is the engine room of the whole subject. Sit with this section a little longer than the others.
Human wants are unlimited. This is not a moral complaint, it is an observation. Satisfy one want and a new one appears immediately. You wanted a cycle in Class 6, a smartphone in Class 9, and now you would quite like a laptop. Your parents wanted a two-room house once, then a car, then a bigger house. Wants also repeat — you ate yesterday, you still want to eat today. There is no point at which a society sits back and says, “That is enough, we need nothing more.”
Resources are scarce. “Scarce” in Economics has a precise meaning that is slightly different from the everyday one. It does not mean rare or nearly finished. It means limited relative to the demand for it. There is a great deal of water on earth, yet clean drinking water is scarce, because at a price of zero far more of it is wanted than is available. Air, on the other hand, is normally a free good — you can breathe as much as you like without depriving anyone.
Resources have alternative uses. This is the third leg, and students forget it most often. If a resource had only one possible use, scarcity would be sad but simple — you would just use it for the one thing. The trouble is that the same hour of a doctor’s time can be spent seeing patients or teaching students; the same steel can become a bridge or a bus. Because resources can go many ways, somebody must decide which way.
Put the three together and you get the economic problem: the problem of choosing how to allocate scarce resources, which have alternative uses, among unlimited and competing wants. Economics, at its heart, is the study of how people and societies make these choices.
Situation. Meher gets Rs 500 pocket money for the month. She would like a novel (Rs 350), a movie outing with friends (Rs 300), a pair of earphones (Rs 900) and to save something for her sister’s birthday gift.
Identify the economic problem. Add her wishes up: 350 + 300 + 900 = Rs 1,550, plus whatever she saves for the gift. Against that stands a scarce Rs 500. Unlimited wants have met a limited resource, and the same Rs 500 could be spent in any of these directions, so it has alternative uses. Meher must therefore choose. Could she take both the novel and the movie? 350 + 300 = Rs 650, which is Rs 150 more than she has, so no. She settles on the movie (Rs 300) and puts the remaining 500 – 300 = Rs 200 towards her sister’s gift.
Point to notice. The moment she chose the movie, the novel was gone for that month. Choice and sacrifice always travel together. Hold on to that feeling — in two sections we will give it the name “opportunity cost”.
Question. Classify each as a scarce (economic) good or a free good, and justify in one line: (a) sunlight falling on a rooftop, (b) solar panels, (c) sea water, (d) bottled drinking water, (e) a doctor’s time.
Answer.
(a) Free good. Sunlight is available in such abundance that at a price of zero everyone who wants it can have it, and my use does not reduce yours.
(b) Scarce good. Solar panels must be manufactured using limited steel, silicon and labour, so they carry a price.
(c) Free good in its raw state — no one pays for sea water at the shore.
(d) Scarce good. Once water is purified, bottled and transported, scarce resources have been used up, so it commands a price.
(e) Scarce good. There are only so many hours in a doctor’s day and many patients wanting them.
The rule behind it. Ask yourself: at a price of zero, would the amount people want exceed the amount available? If yes, it is scarce. Notice also from (a) and (b) that the same underlying thing (sun energy) can be free in one form and scarce in another once human effort is added.
Why it works. Every later chapter is really a special case of this section. Demand theory asks how a consumer with a scarce income chooses between goods. Cost theory asks how a producer with scarce inputs chooses a level of output. Market theory asks how prices settle those choices for society. Scarcity is not one topic among many — it is the reason the subject exists at all.
The Three Central Problems Of An Economy
Scarcity forces choice. But an economy is not choosing one thing — it is choosing thousands of things every day. Economists have found that all of those decisions boil down to three questions. They are called the central problems, and they are central for two reasons: every economy in history has faced them, and they arise directly out of scarcity. If resources were unlimited, none of these three questions would need asking.
Problem 1 — What To Produce And In What Quantities?
Since the economy cannot produce everything, it must decide which goods to make and how much of each. This has two layers. First, the choice between broad categories: how much of the country’s effort goes into consumer goods (food, clothes, phones) versus capital goods (machines, roads, power plants)? Second, within each category: how many tonnes of wheat versus how many tonnes of sugarcane?
Notice why this is a problem and not just a decision. Producing more defence equipment means the very same steel, engineers and factory hours cannot make school buses. There is a genuine trade-off, and somebody — the market through prices, or the government through planning — has to settle it.
Problem 2 — How To Produce?
Once you know what to make, you must choose the technique. Almost every good can be produced in more than one way, and the two standard choices are:
- Labour-intensive technique — more labour relative to capital. Think of a road being built by a large gang of workers with hand tools.
- Capital-intensive technique — more capital relative to labour. Think of the same road built by three machines and six operators.
Which is “better”? There is no universal answer, and that is exactly what makes it a problem. The sensible rule is to choose the technique that produces the required output at the least cost, given the resources the country actually has. A country with abundant labour and scarce capital will often find labour-intensive methods cheaper and socially useful, because they also create employment.
Problem 3 — For Whom To Produce?
The goods are made. Now, who gets them? This is the problem of distribution — how the national output (or national income) is shared among the people of the country. In a market economy, you get roughly what your resources earn: wages for labour, rent for land, interest for capital, profit for enterprise. Those who own more, or own scarcer skills, get more.
This problem has two sides that examiners like to see mentioned together: the question of who gets how much, and the resulting question of equity — whether the distribution is fair, and whether the government should step in with taxes, subsidies and welfare schemes to change it.
Question. State which central problem each situation illustrates.
(a) A state government decides to build 400 new primary health centres instead of a new expressway.
What to produce. Scarce funds are being allocated between two different goods.
(b) A garment factory replaces forty tailors with eight automatic stitching machines.
How to produce. The firm is switching from a labour-intensive to a capital-intensive technique.
(c) The Union Budget raises income tax on very high incomes and expands free ration coverage.
For whom to produce. This changes how the output of the economy is distributed among people.
(d) A sugar mill decides to divert part of its cane juice to ethanol instead of sugar.
What to produce. The same scarce input is being allocated between two different final goods.
Question (6 marks). “The central problems of an economy arise on account of scarcity.” Explain the three central problems in the light of this statement.
Model answer.
Introduction (1 mark). Resources in every economy are scarce in relation to unlimited wants, and they have alternative uses. Because of this, an economy cannot produce everything it wants and is compelled to make choices. These choices give rise to three central problems.
1. What to produce and in what quantities (about 2 marks). The economy must decide which goods to produce with its limited resources and in what amounts — for example, how much of its resources should go to consumer goods and how much to capital goods. Devoting resources to one good automatically means fewer resources for another, so the economy must select the combination that gives the greatest satisfaction to society.
2. How to produce (about 2 marks). The economy must choose a technique of production — labour-intensive or capital-intensive. The problem arises because the same good can be produced by different combinations of scarce factors. The technique that produces the desired output at the least cost, given the country’s factor endowment, is generally preferred.
3. For whom to produce (about 1 mark). Since output is limited, the economy must decide how it will be distributed among the people. This raises the question of who gets how much, and whether the resulting distribution is equitable.
Conclusion. Each of the three problems would disappear if resources were unlimited. Hence the central problems are a direct consequence of scarcity.
Question (3 marks). A country has plenty of unskilled workers and very little machinery. Which technique of production should it generally adopt, and why? Which central problem does this address?
Answer. It should generally adopt a labour-intensive technique. Two reasons, and give both:
(i) Cost. A factor that is abundant tends to be relatively cheap, and a factor that is scarce tends to be relatively expensive. Since labour is abundant here and capital is scarce, producing with more labour and less machinery will usually give the lower cost of production for the same output.
(ii) Employment. Labour-intensive methods absorb more workers, which helps reduce unemployment and improves the spread of income in a country with surplus labour.
This is the central problem of how to produce, because it concerns the choice of technique, not the choice of which good to make.
Where students slip. Many write “capital-intensive, because machines are modern and efficient”. Modernity is not the test. The test is relative cost given the resources the country actually possesses.
Why it works. These three questions are not an arbitrary list somebody invented. Try to think of a fourth economic decision a society must make — you will find it collapses into one of these three. That is why the same three problems appear in an ancient village economy and in a trillion-dollar modern one.
Opportunity Cost: The Real Price Of Every Choice
This is the single most useful idea in the whole of Class 11 Economics, and it is beautifully simple. When you choose one thing, you give up the chance to have something else. Opportunity cost is the value of the next-best alternative that you gave up.
Read that definition again and notice two words doing all the work: “next-best”. Not the total of everything you sacrificed — just the one best option you turned down. If on Sunday you could study, or play cricket, or sleep, and you rank cricket above sleeping, then choosing to study has an opportunity cost of the cricket match, not “cricket plus sleep”.
The everyday version is the one to keep in your head. You have Rs 300 and a free evening. You can buy a book or watch a movie, not both. You pick the movie. The true cost of the movie is not “Rs 300” — money is only a token. The true cost is the book you did not read. That is opportunity cost, and once you start seeing it you cannot un-see it.
Question. After graduating, Ananya has exactly three options for the coming year: run a coaching centre and earn Rs 2,40,000; take a bank job at Rs 3,00,000; or freelance as a designer for Rs 2,70,000. She chooses the coaching centre. Find her opportunity cost.
Solution, step by step.
Step 1 — Identify what she chose: the coaching centre, worth Rs 2,40,000.
Step 2 — List what she gave up: bank job Rs 3,00,000 and freelancing Rs 2,70,000.
Step 3 — Pick the best of the forgone options. Compare 3,00,000 and 2,70,000. The larger is Rs 3,00,000, the bank job.
Step 4 — Opportunity cost = Rs 3,00,000 (the bank job forgone).
Two traps to avoid. Do not add 3,00,000 + 2,70,000 = Rs 5,70,000; opportunity cost is never a total of all sacrifices. And do not subtract to get 3,00,000 – 2,40,000 = Rs 60,000; that difference is her net loss from the decision, which is a different (and also interesting) number, but it is not what the term “opportunity cost” means.
Question. One hectare of land can produce either 40 quintals of wheat or 25 quintals of mustard. Find (i) the opportunity cost of 1 quintal of wheat, and (ii) the opportunity cost of 1 quintal of mustard.
Solution. The whole hectare gives 40 wheat OR 25 mustard, so the two are directly exchangeable: 40 wheat is equivalent to 25 mustard.
(i) Divide both sides by 40 to get the cost of one wheat: 1 quintal of wheat corresponds to 25 / 40 = 0.625 quintal of mustard (that is 5/8 of a quintal).
(ii) Divide both sides by 25 to get the cost of one mustard: 1 quintal of mustard corresponds to 40 / 25 = 1.6 quintals of wheat (that is 8/5).
Sanity check. The two answers should be reciprocals of each other: 0.625 multiplied by 1.6 = 1. They are. Whenever you compute a pair of opportunity costs like this, multiply them together — if you do not get 1, you have made an arithmetic slip.
Notice. Not a single rupee appeared in this answer. Opportunity cost is fundamentally about real things given up; money is just a convenient measuring tape.
Question (4 marks). Define opportunity cost. Explain, with one example each, why (a) an unemployed resource has zero opportunity cost, and (b) opportunity cost is important for an economy.
Model answer.
Definition (1 mark). Opportunity cost is the value of the next-best alternative forgone when a particular choice is made.
(a) Unemployed resources (1.5 marks). Opportunity cost arises only when a resource has to be withdrawn from some other use. If a machine is lying completely idle in a closed workshop and has no alternative employment, then putting it to work sacrifices nothing at all. Hence its opportunity cost is zero. For the same reason, an economy operating well below its capacity can expand production of one good without reducing the other, because it is drawing on unused resources rather than transferring employed ones.
(b) Importance for an economy (1.5 marks). Since resources are scarce, an economy must judge every proposal against what it gives up. Suppose a government has funds enough for either a new metro line or 300 rural schools. Comparing the two allows it to choose the option with the higher benefit relative to what is sacrificed. Opportunity cost thus becomes the practical yardstick for allocating scarce resources, and it is the basis of the trade-off shown by the production possibility curve.
Why it works. Opportunity cost is the bridge between the philosophy of the first half of this chapter and the diagram of the second half. Scarcity says “you must choose”. Opportunity cost says “here is what choosing costs you”. The production possibility curve, coming up next, is simply a picture of that cost drawn for a whole economy. Do not move on until this section feels comfortable — everything ahead leans on it.
The Production Possibility Curve: Schedule And Diagram
Everything so far has been in words. Now we draw it. The production possibility curve (PPC), also called the production possibility frontier (PPF), is a curve showing the different combinations of two goods that an economy can produce when it uses all its resources fully and efficiently, with a given technology.
Read that definition slowly, because it hides three assumptions that every PPC question depends on:
- Only two goods are produced. Not because the real world has two goods, but because a sheet of paper has two axes. It is a simplification, not a claim.
- Resources are fixed in quantity and are fully and efficiently employed. Nothing is lying idle and nothing is being wasted.
- Technology is given and unchanged during the period we are looking at.
- Resources are not equally efficient in producing both goods, and they can be shifted from one use to the other. This last one is what makes the curve bend, as you will see in the next section.
Let us build one from scratch. Imagine a small factory town, Sunrise Sports, whose workers, machines and materials can be used to make either cricket bats or footballs. Here are all the combinations it can produce if it wastes nothing.
| Possibility | Cricket bats (Good X) | Footballs (Good Y) | Footballs sacrificed for 1 more bat | MRT (Y : X) |
|---|---|---|---|---|
| A | 0 | 30 | — | — |
| B | 1 | 28 | 30 − 28 = 2 | 2 : 1 |
| C | 2 | 24 | 28 − 24 = 4 | 4 : 1 |
| D | 3 | 18 | 24 − 18 = 6 | 6 : 1 |
| E | 4 | 10 | 18 − 10 = 8 | 8 : 1 |
| F | 5 | 0 | 10 − 0 = 10 | 10 : 1 |
Look down the fourth column: 2, 4, 6, 8, 10. Every extra bat costs more footballs than the previous one did. Hold that thought — it is the whole of the next section.
Now plot the six pairs, with bats on the horizontal axis and footballs on the vertical axis, and join them. You get this:
Question. Using the Sunrise Sports schedule, answer: (i) the maximum footballs the town can make, (ii) the maximum bats, (iii) the opportunity cost of moving from B to D, and (iv) the opportunity cost per extra bat over that move.
Solution.
(i) Maximum footballs = 30 thousand, at possibility A where zero bats are made. All resources go to footballs.
(ii) Maximum bats = 5 thousand, at possibility F where zero footballs are made.
(iii) B is (1 bat, 28 footballs) and D is (3 bats, 18 footballs). Footballs given up = 28 − 18 = 10 thousand footballs. That is the opportunity cost of the move.
(iv) Bats gained = 3 − 1 = 2. Cost per extra bat = 10 ÷ 2 = 5 footballs per bat on average over that stretch.
Note the wording. Part (iii) asks for the opportunity cost of the move, so the answer is the total sacrifice, 10. Part (iv) asks per unit, so we divide. Examiners switch between these two phrasings deliberately — read the question twice.
Question (4 marks). What is a production possibility curve? State the assumptions on which it is based.
Model answer.
Meaning (1 mark). A production possibility curve is a curve showing the various combinations of two goods that an economy can produce with its given resources and given technology, when those resources are fully and efficiently utilised.
Assumptions (3 marks, roughly ¾ mark each).
(i) The economy produces only two goods.
(ii) The quantity of resources available is fixed during the period considered.
(iii) Resources are fully employed and efficiently utilised, so no output is being wasted.
(iv) The state of technology is given and remains constant.
(v) Resources can be transferred from the production of one good to the other, but they are not equally efficient in both uses.
Why assumption (v) matters. If resources were equally good at both jobs, the PPC would be a straight line rather than a curve. Mentioning this earns you the presentation marks examiners quietly award for showing you understand rather than memorised.
Why it works. The PPC turns an abstract sentence — “scarcity forces trade-offs” — into something you can point at. The curve is the boundary of the possible. Everything the economy might wish for beyond it is a daydream; everything comfortably inside it is a waste. That is a lot of meaning packed into one bent line.
Marginal Rate Of Transformation And Why The PPC Is Concave
The marginal rate of transformation (MRT) is a grand name for a very ordinary calculation: how many units of Good Y must be sacrificed to produce one more unit of Good X. In symbols,
MRT = ΔY / ΔX = units of Y given up ÷ units of X gained
MRT is simply opportunity cost measured at the margin — that is, for one extra unit rather than for a big jump. It is also the slope of the PPC (ignoring the minus sign). So MRT, opportunity cost and slope of PPC are three names circling the same idea. If a question asks for any one of them, the arithmetic is identical.
Now the important observation. Go back to the Sunrise Sports column: the MRT ran 2, 4, 6, 8, 10. It rises. This is the law of increasing marginal opportunity cost, and it is the reason the PPC bends the way it does.
But why should it rise? This is the part worth understanding rather than memorising, so let me walk you through it with the factory.
Sunrise Sports starts at A, making only footballs. Every worker and machine is stitching leather. Now the town decides to make its first thousand bats. Which resources will it move across? Obviously the ones that are worst at footballs and best at bats — the carpenters, the wood lathes, the people who were clumsy with leather anyway. Moving them costs very few footballs: only 2.
The town then wants a second thousand bats. But the ideal bat-makers have already been moved. Now it must pull across people who were reasonably good at footballs. The sacrifice climbs to 4. Push further and it must eventually drag away the master leather-stitchers themselves, who are superb at footballs and hopeless with wood. By the last stretch, one more thousand bats costs a painful 10 thousand footballs.
So the cause is this: resources are not equally efficient in the production of both goods. As you specialise more and more in one good, you are forced to use resources that are progressively less suited to it. Opportunity cost therefore rises, and a curve whose slope keeps getting steeper is, geometrically, concave to the origin.
• MRT increasing → PPC is concave to the origin (bowed outward). This is the normal case.
• MRT constant → PPC is a straight downward-sloping line. Happens when resources are equally efficient in both goods.
• MRT decreasing → PPC is convex to the origin. Economically unusual and generally not expected in the normal case.
In every case the PPC slopes downward, because more of one good always means less of the other when resources are fully employed.
Question. Greenfield Farm can produce wheat and sugarcane in the following combinations (in tonnes). Calculate MRT at each stage and state the shape of the resulting PPC.
Wheat: 0, 1, 2, 3, 4, 5 | Sugarcane: 25, 24, 22, 19, 15, 10
Solution. Wheat rises by 1 each time, so ΔX = 1 throughout and MRT is just the sugarcane sacrificed.
0 → 1 wheat: 25 − 24 = 1, so MRT = 1 : 1
1 → 2 wheat: 24 − 22 = 2, so MRT = 2 : 1
2 → 3 wheat: 22 − 19 = 3, so MRT = 3 : 1
3 → 4 wheat: 19 − 15 = 4, so MRT = 4 : 1
4 → 5 wheat: 15 − 10 = 5, so MRT = 5 : 1
Answer. MRT = 1, 2, 3, 4, 5 — steadily increasing. Therefore the PPC is concave to the origin, which is the normal shape, and it confirms the law of increasing marginal opportunity cost.
Self-check. Add the five sacrifices: 1 + 2 + 3 + 4 + 5 = 15. The sugarcane fell from 25 to 10, a drop of 15. The two agree, so no arithmetic slip. Always run this check — it takes five seconds and catches almost every careless error.
Question. A workshop can make chairs and tables in these combinations — Chairs: 0, 1, 2, 3, 4 and Tables: 40, 30, 20, 10, 0. Find the MRT and describe the PPC. What does this tell you about the workshop’s resources?
Solution.
0 → 1 chair: 40 − 30 = 10, MRT = 10 : 1
1 → 2 chairs: 30 − 20 = 10, MRT = 10 : 1
2 → 3 chairs: 20 − 10 = 10, MRT = 10 : 1
3 → 4 chairs: 10 − 0 = 10, MRT = 10 : 1
Answer. MRT is constant at 10 : 1. A constant slope means the PPC is a straight downward-sloping line, not a curve.
Interpretation (this is where the marks are). A constant MRT tells us the workshop’s resources are equally efficient in making chairs and tables. No matter which resource is transferred, the sacrifice is the same, so opportunity cost never rises. Do not simply write “the PPC is a straight line” and stop — always add the reason.
Question. An economist claims the following is a production possibility schedule for an economy — Good X: 0, 1, 2, 3 and Good Y: 50, 47, 45, 44. Comment on the shape it implies and whether it represents the usual case.
Solution. Compute the MRT first, always.
0 → 1: 50 − 47 = 3, MRT = 3 : 1
1 → 2: 47 − 45 = 2, MRT = 2 : 1
2 → 3: 45 − 44 = 1, MRT = 1 : 1
Comment. MRT is falling (3, 2, 1), which means marginal opportunity cost is decreasing. Graphically the curve would be convex to the origin rather than concave.
This is not the usual case. It would require resources to become better and better suited to Good X the more of it we produce, which contradicts the ordinary assumption that resources are unequally efficient and that the best-suited ones are transferred first. The schedule is therefore internally consistent as arithmetic but economically atypical.
What it still gets right. Notice Y does keep falling as X rises, so the curve is still downward sloping. Downward slope comes from scarcity and applies always; concavity comes from increasing MRT and is the normal-but-not-universal case. Keep those two reasons separate in your answer.
Why it works. MRT is where the words and the picture finally lock together. Opportunity cost from the previous section is a number; the slope of the PPC is a geometric feature; the law of increasing marginal opportunity cost says that number keeps growing, which is exactly why the geometry bends. One idea, three languages.
Points On, Inside And Outside The Curve
A PPC divides the whole diagram into three zones, and each zone tells a different story about the economy. This is one of the most frequently asked bits of the chapter, and thankfully it is easy once you have the right mental picture.
- A point ON the curve — resources are fully and efficiently employed. The economy is doing as well as it possibly can with what it has. Every point on the curve is efficient; the economy simply has to choose which combination it prefers.
- A point INSIDE the curve (below and to the left) — the combination is attainable, but the economy is underutilising its resources. There is either unemployment of resources or inefficient use of them. This is a wasteful position: the economy could produce more of one good without giving up any of the other.
- A point OUTSIDE the curve (above and to the right) — unattainable with the present resources and technology. It is a wish, not a plan. The economy can only reach it if resources grow or technology improves, which shifts the whole curve outward.
Here is the practical test you should use in the exam. Take the number of Good X in the point, look up the schedule to find how much Y the economy can make with that much X, and compare:
- Y in the point equals the schedule value → the point is on the curve.
- Y in the point is less than the schedule value → the point is inside (underutilisation).
- Y in the point is more than the schedule value → the point is outside (unattainable).
Question. Using the Sunrise Sports schedule (bats 0,1,2,3,4,5 against footballs 30,28,24,18,10,0), classify each combination as on, inside or outside the PPC, and interpret it.
(a) (2 bats, 20 footballs) (b) (3 bats, 22 footballs) (c) (4 bats, 10 footballs) (d) (0 bats, 25 footballs)
Solution.
(a) At 2 bats the schedule allows 24 footballs. Here only 20 are being produced, and 20 < 24. The point lies inside the curve. Interpretation: resources are underutilised — the town could make 4 thousand more footballs without giving up a single bat. This is point U in our diagram.
(b) At 3 bats the schedule allows 18 footballs. This point claims 22, and 22 > 18. The point lies outside the curve and is unattainable with present resources and technology. This is point W in our diagram.
(c) At 4 bats the schedule gives exactly 10 footballs. 10 = 10, so the point lies on the curve — full and efficient employment of resources. This is point E.
(d) At 0 bats the schedule allows 30 footballs, but only 25 are produced. 25 < 30, so the point is inside the curve. Even though the town is making no bats at all, it is still wasting resources.
Lesson from (d). Specialising entirely in one good does not automatically make you efficient. Efficiency is about whether you are on the frontier, not about which end of it you sit at.
Question (4 marks). An economy is producing at a point inside its production possibility curve. What does this indicate? Suggest how the economy could move on to the curve, and explain whether this involves any opportunity cost.
Model answer.
What it indicates (1.5 marks). A point inside the PPC shows that the economy’s resources are not being fully or efficiently employed. There is either unemployment of resources or their inefficient utilisation, so the economy is producing less of both goods than it is capable of producing.
How to move on to the curve (1.5 marks). The economy does not need any new resources. It simply needs to put the existing idle resources to work and use employed resources more efficiently — for example by removing unemployment, improving worker skills, better organisation of production, or ending wasteful practices. As idle resources are absorbed, output of both goods can rise until the economy reaches the frontier.
Opportunity cost (1 mark). This movement involves no opportunity cost, because nothing has to be sacrificed. The extra output comes from resources that were previously producing nothing at all. This is exactly why a point inside the curve is described as wasteful — free gains are available and are not being taken.
Contrast worth adding. Once the economy is on the curve, further increase in one good does carry an opportunity cost, because resources must then be taken away from the other good.
Why it works. The frontier is a boundary between what an economy can and cannot do. Inside is regret, on it is efficiency, outside is ambition. Almost every economic policy discussion you will ever hear is really an argument about which of these three zones a country is sitting in.
Shifts And Rotations Of The Production Possibility Curve
So far the curve has stayed put. But resources grow, technology improves, floods destroy crops and epidemics reduce the workforce. When any of the given things in our assumptions change, the whole curve moves. Getting this right is largely a matter of asking one careful question: does the change affect both goods, or only one?
Case 1 — Parallel Shift Of The Whole Curve (Both Goods Affected)
If resources increase or technology improves for both goods, the entire curve shifts rightward / outward — this is economic growth. Both intercepts move out. Causes include a growing labour force, more capital through investment, discovery of new mineral deposits, or a general improvement in skills and technology.
If resources shrink or are destroyed, the curve shifts leftward / inward. Causes include a severe earthquake, a war destroying factories, or a large fall in the working population.
Case 2 — Rotation Of The Curve (Only One Good Affected)
If technology improves for only one good, the curve rotates. The intercept of the affected good moves outward, while the intercept of the unaffected good stays exactly where it was. This is the case examiners use to separate the students who understood from the students who memorised.
• A movement along the PPC (say from B to D) means the economy is re-allocating its existing resources between the two goods. The curve does not move. There is an opportunity cost.
• A shift of the PPC means the resources or technology themselves have changed. The curve itself relocates.
Ask: has the economy’s capacity changed, or only its choice? Capacity changed → shift. Only choice changed → movement along.
Question. Sunrise Sports adopts a new stitching machine that raises football output by 50% at every level of bat production. Bat technology is unchanged. Construct the new schedule and describe what happens to the PPC.
Solution. Multiply every football figure by 1.5 and leave the bat figures alone.
0 bats: 30 × 1.5 = 45 | 1 bat: 28 × 1.5 = 42 | 2 bats: 24 × 1.5 = 36
3 bats: 18 × 1.5 = 27 | 4 bats: 10 × 1.5 = 15 | 5 bats: 0 × 1.5 = 0
Description. The football intercept rises from 30 to 45, but the bat intercept stays at 5 — because with all resources in bats, the new stitching machine is of no use whatsoever. The curve therefore rotates outward about the point F on the horizontal axis, rather than shifting bodily. The economy can now have more footballs at every positive level of bats, but its maximum bat output has not improved at all.
Check the new MRT. Sacrifices are now 45−42 = 3, 42−36 = 6, 36−27 = 9, 27−15 = 12, 15−0 = 15. So MRT = 3, 6, 9, 12, 15 — still increasing, so the curve is still concave to the origin. Sensible: improving one technology changes the position of the frontier, not the basic reason it bends.
Question. State with reason the effect of each event on an economy’s PPC for food and clothing.
(a) A large number of workers migrate into the country. Resources have increased and workers can produce both goods, so the entire PPC shifts outward (rightward). Both intercepts rise.
(b) A new high-yielding seed variety raises food output only. Only one good benefits, so the PPC rotates outward about the clothing intercept. Maximum food rises; maximum clothing is unchanged.
(c) The government asks farmers to grow less food and more cotton for clothing. No change in resources or technology, only in how existing resources are allocated. This is a movement along the existing PPC, and it carries an opportunity cost in terms of food forgone.
(d) A prolonged drought destroys a quarter of the arable land. Resources have fallen and land is used for both goods, so the PPC shifts inward (leftward).
(e) Long-term unemployment is reduced through a public works programme. This is the tricky one. The economy’s resources have not increased — the same people were always there. So the PPC does not shift. What happens is a movement from a point inside the curve towards a point on it.
How to be safe. For each event, ask in order: (1) Has the total stock of resources or technology changed? If no, it is a movement, not a shift. (2) If yes, does it affect both goods or one? Both → shift; one → rotate.
Why it works. The PPC is a snapshot of an economy’s capacity at one moment. Shifts are the story of that capacity changing over time — which is, essentially, the story of economic growth and of every disaster that sets a country back. That is why this small diagram keeps reappearing right up to university level.
Microeconomics And Macroeconomics: Meaning And Difference
Economics is a huge subject, so it is studied through two lenses. The difference is essentially one of zoom level, and a simple picture will fix it forever: microeconomics studies the individual trees, macroeconomics studies the forest.
Microeconomics studies the economic behaviour of individual units — a single consumer, a single firm, a single household, a single market. It asks questions like: how does a consumer decide how many kilos of rice to buy? How does a shoe factory decide its output? How is the price of onions determined in the mandi? The word comes from the Greek mikros, meaning small.
Macroeconomics studies the economy as a whole, dealing with aggregates and averages. It asks: what is the national income of India? Why is the general price level rising? What is the overall level of unemployment? From makros, meaning large.
Class 11 Part B is Introductory Microeconomics, so this year you will live in the world of individual consumers and firms. Macroeconomics arrives properly in Class 12.
| Basis | Microeconomics | Macroeconomics |
|---|---|---|
| Meaning | Studies the economic behaviour of individual units of the economy. | Studies the economy as a whole, using aggregates. |
| Unit of study | A consumer, a firm, a household, a single market. | The whole economy, all consumers and all firms together. |
| Main problem addressed | Price determination and allocation of resources. | Determination of income and employment in the economy. |
| Typical variables | Individual demand, individual supply, price of a good, output of a firm. | National income, aggregate demand, general price level, total employment. |
| Also called | Price theory. | Income and employment theory. |
| Example question | Why did the price of tomatoes rise in this mandi? | Why is the general price level in India rising? |
Question. Classify each as micro or macro and give a one-line reason.
(a) The price of wheat in the Karnal mandi rose by 8% last month. — Micro. It concerns the price of a single commodity in a single market.
(b) India’s national income grew last financial year. — Macro. National income is an aggregate of the whole economy.
(c) A large steel company decided to cut its output by 15%. — Micro. Even though the company is huge, it is a single firm. Size is irrelevant.
(d) The overall rate of unemployment in the country fell. — Macro. It refers to total employment in the economy.
(e) The Reddy household decided to spend less on eating out. — Micro. A single household’s consumption decision.
(f) Total savings of all households in the economy increased. — Macro. The word “total … of all” turns an individual variable into an aggregate.
Compare (e) and (f) carefully. Both are about household saving. What flips the classification is the words “of all households in the economy”. Watch for aggregating words — total, national, general, overall, aggregate, economy-wide.
Question (3 marks). Distinguish between microeconomics and macroeconomics on the basis of (i) meaning, (ii) central problem studied, and (iii) an example.
Model answer. Present it as a table if you have time; otherwise write it as three clean pairs.
(i) Meaning. Microeconomics studies the economic behaviour of individual units such as a consumer or a firm, whereas macroeconomics studies the economy as a whole through aggregates.
(ii) Central problem. Microeconomics is mainly concerned with the determination of price and the allocation of resources, whereas macroeconomics is mainly concerned with the determination of the level of income and employment in the economy.
(iii) Example. Studying how the price of sugar is determined in a market is microeconomics; studying why the general price level in the country is rising is macroeconomics.
Presentation note. In a “distinguish between” question, always write both halves in the same sentence using “whereas” or “while”. Writing three lines about micro and then three lines about macro is a weaker answer and some marking schemes penalise it.
Why it works. The split exists because the two lenses genuinely need different tools. Something true of one household — spending less lets you save more — can be false for the whole economy at once, because one person’s spending is another person’s income. That is a Class 12 puzzle, but it is exactly why economists refused to treat the economy as simply one big household.
Positive Economics And Normative Economics
The last idea in the chapter, and a genuinely useful one for life beyond the exam. Economists make two very different kinds of statement, and mixing them up causes a great deal of confused arguing.
Positive economics deals with statements about what is, what was, or what will be. These are statements of fact. They may be right or wrong, but crucially they can be tested against evidence. “The price of petrol rose by Rs 4 last month” is positive — go and check the data.
Normative economics deals with statements about what ought to be. These involve value judgements, opinions about what is desirable or fair. They cannot be tested as true or false, because they depend on what you value. “The government ought to make petrol cheaper for farmers” is normative — reasonable people can disagree and no dataset settles it.
| Basis | Positive Economics | Normative Economics |
|---|---|---|
| Nature of statement | Deals with what is, what was or what will be — statements of fact. | Deals with what ought to be — statements of opinion. |
| Value judgement | Free of value judgements; purely descriptive. | Based on value judgements about what is desirable. |
| Verifiability | Can be verified or disproved using facts and data. | Cannot be verified as true or false; open to disagreement. |
| Question answered | What is happening, and why? | What should be done about it? |
| Signal words | is, was, will be, rose, fell, causes. | should, ought to, must, fair, unjust, better, desirable. |
| Example | A rise in the price of onions reduced the quantity demanded. | Onions should be sold at a subsidised rate to poor families. |
(a) “India’s rate of inflation was higher this year than last year.” — Positive. A factual claim that can be checked against price data.
(b) “Inflation should be brought down even if it costs some jobs.” — Normative. The word “should”, plus a judgement that lower inflation is worth more than the jobs lost.
(c) “A rise in the tax on cigarettes will reduce cigarette consumption.” — Positive. It is a prediction, and predictions are testable. Do not be misled by the fact that it is about the future.
(d) “The government ought to spend more on rural schools than on stadiums.” — Normative. “Ought to” plus a ranking of what matters more.
(e) “Free electricity to farmers has increased groundwater extraction.” — Positive. Reports an observed consequence, with no opinion on whether the policy is good.
(f) “Free electricity to farmers is an unfair burden on other taxpayers.” — Normative. The word “unfair” is a pure value judgement.
Look at (e) and (f) together. Same policy, two completely different kinds of statement. Positive economics tells us what a policy does; normative economics argues about whether we want that. Good policy debate needs both, kept separate.
Question (4 marks). Distinguish between positive and normative economics. Is the statement “the unemployment rate in India is 2%” positive or normative, even though the figure may be incorrect?
Model answer.
Distinction (3 marks). Positive economics deals with statements about what is, what was or what will be. Such statements are descriptive, free from value judgements, and can be verified or disproved with the help of facts and data. Normative economics, on the other hand, deals with statements about what ought to be. Such statements involve value judgements about what is desirable or fair, and they cannot be verified as true or false since they depend on individual opinion. For example, “the price of rice rose by 5%” is positive, while “the price of rice should be controlled by the government” is normative.
Classification of the given statement (1 mark). It is a positive statement. The classification depends on the nature of the statement, not on whether it happens to be correct. Since the claim is about a matter of fact, it can in principle be checked against employment data and shown to be true or false — and being capable of verification is precisely what makes a statement positive. A wrong positive statement remains positive; it is simply a wrong one.
Why it works. This distinction is the discipline’s honesty policy. Economics can tell you with reasonable confidence what a policy will do; it cannot tell you whether you should want that outcome, because that depends on what a society values. Keeping the two apart is what stops analysis from quietly turning into propaganda.
Practice Worksheet With Full Answers
Ten questions, mixed marks, built exactly the way this unit is asked in the paper. Please do this honestly: write your full answer in your notebook first, then open the “Show Answer” box and compare. Reading a solved answer feels productive and teaches you almost nothing. Writing one and then correcting it is where the marks actually come from.
Q1 (1 mark). Define opportunity cost.
Show Answer
Opportunity cost is the value of the next-best alternative forgone when a particular choice is made.
Marking note. The two words that earn the mark are “next-best”. A definition that says only “the alternative given up” is usually treated as incomplete.
Q2 (1 mark each, 3 total). State whether each is studied under microeconomics or macroeconomics: (a) the output decision of a single sugar mill; (b) the general price level in India; (c) determination of the price of milk in a local market.
Show Answer
(a) Microeconomics — it concerns a single firm, which is an individual unit.
(b) Macroeconomics — the general price level is an aggregate for the whole economy.
(c) Microeconomics — price determination of a single commodity in a single market.
Q3 (3 marks) — numerical. An economy produces Good X and Good Y. When X output is 0, 1, 2, 3 and 4 units, Y output is 18, 17, 15, 12 and 8 units respectively. Calculate the marginal rate of transformation at each stage and state, with reason, the shape of the PPC.
Show Answer
X increases by 1 unit at every step, so MRT = units of Y sacrificed ÷ 1.
0 → 1 unit of X: 18 − 17 = 1, so MRT = 1 : 1
1 → 2 units of X: 17 − 15 = 2, so MRT = 2 : 1
2 → 3 units of X: 15 − 12 = 3, so MRT = 3 : 1
3 → 4 units of X: 12 − 8 = 4, so MRT = 4 : 1
Shape. MRT rises steadily (1, 2, 3, 4), which means marginal opportunity cost is increasing. Therefore the PPC is concave to the origin and slopes downward.
Reason. Resources are not equally efficient in producing both goods. As more X is produced, resources progressively less suited to X must be transferred from Y, so each additional unit of X costs more units of Y.
Check. 1 + 2 + 3 + 4 = 10, and Y fell from 18 to 8, a drop of 10. The figures agree.
Q4 (3 marks) — numerical. Greenfield Farm’s production possibilities are — Wheat: 0, 1, 2, 3, 4, 5 tonnes and Sugarcane: 25, 24, 22, 19, 15, 10 tonnes. Classify each of these actual output combinations as on, inside or outside the PPC, and interpret: (a) 2 wheat and 20 sugarcane; (b) 4 wheat and 17 sugarcane; (c) 3 wheat and 19 sugarcane.
Show Answer
(a) 2 wheat, 20 sugarcane. At 2 tonnes of wheat the schedule permits 22 tonnes of sugarcane. Since 20 < 22, the point lies inside the PPC. The farm’s resources are underutilised — it could produce 2 more tonnes of sugarcane without reducing wheat at all.
(b) 4 wheat, 17 sugarcane. At 4 tonnes of wheat the schedule permits only 15 tonnes of sugarcane. Since 17 > 15, the point lies outside the PPC and is unattainable with the present resources and technology.
(c) 3 wheat, 19 sugarcane. The schedule gives exactly 19 at 3 tonnes of wheat. The point lies on the PPC, indicating full and efficient employment of resources.
Q5 (4 marks) — numerical. A country can produce cloth and steel in these combinations — Cloth (lakh metres): 0, 10, 20, 30, 40 and Steel (thousand tonnes): 80, 60, 40, 20, 0. (i) Calculate MRT at each stage. (ii) What is the shape of the PPC and what does it tell you about the country’s resources? (iii) Find the opportunity cost of raising cloth output from 10 to 30 lakh metres.
Show Answer
(i) Here cloth rises by 10 units each time, so you must divide — this is where careless students slip.
0 → 10 cloth: steel lost = 80 − 60 = 20, so MRT = 20 ÷ 10 = 2 : 1
10 → 20 cloth: 60 − 40 = 20, MRT = 20 ÷ 10 = 2 : 1
20 → 30 cloth: 40 − 20 = 20, MRT = 20 ÷ 10 = 2 : 1
30 → 40 cloth: 20 − 0 = 20, MRT = 20 ÷ 10 = 2 : 1
(ii) MRT is constant at 2 : 1. A constant slope means the PPC is a straight downward-sloping line rather than a concave curve. This tells us the country’s resources are equally efficient in producing cloth and steel, so transferring any resource costs the same sacrifice and opportunity cost never rises.
(iii) At 10 lakh metres of cloth, steel = 60. At 30 lakh metres, steel = 20. Steel sacrificed = 60 − 20 = 40 thousand tonnes. Per unit of cloth, that is 40 ÷ 20 = 2 thousand tonnes of steel per lakh metre — consistent with the constant MRT of 2 : 1, which is a good sign that the working is right.
Q6 (3 marks) — numerical. After finishing his studies, Rahul has exactly three options for the year: open a bookshop and earn Rs 4,50,000; take a salaried job paying Rs 5,20,000; or run a food stall earning Rs 4,80,000. He chooses the bookshop. (i) What is his opportunity cost? (ii) A friend says the opportunity cost is Rs 10,00,000. Explain his error.
Show Answer
(i) Rahul chose the bookshop, so he gave up the salaried job (Rs 5,20,000) and the food stall (Rs 4,80,000). The next-best of these is the larger figure, Rs 5,20,000. Hence his opportunity cost is Rs 5,20,000, the salaried job forgone.
(ii) The friend has added the two forgone options: 5,20,000 + 4,80,000 = Rs 10,00,000. This is wrong because Rahul could never have had both simultaneously — he had to pick exactly one alternative. Opportunity cost counts only the single best alternative sacrificed, never the sum of all alternatives.
Extra point worth a line. Note also that Rs 5,20,000 − Rs 4,50,000 = Rs 70,000 is the amount by which he is worse off than his best alternative. That is a meaningful figure, but it is his net loss, not his opportunity cost.
Q7 (4 marks). Distinguish between positive and normative economics on any two bases. Then classify: (a) “Raising the tax on sugary drinks will reduce their sales.” (b) “The government should provide free healthcare to all citizens.”
Show Answer
Distinction (2 marks).
Basis 1 — Nature. Positive economics deals with statements about what is, what was or what will be, whereas normative economics deals with statements about what ought to be.
Basis 2 — Verifiability. Positive statements are free from value judgements and can be verified or disproved with facts and data, whereas normative statements rest on value judgements and cannot be tested as true or false.
Classification (2 marks).
(a) Positive. It is a prediction about what will happen, and it can be checked against sales data after the tax is imposed. Being about the future does not make a statement normative.
(b) Normative. The word “should” signals a value judgement about what the government ought to do; no data can prove or disprove it.
Q8 (6 marks). Explain the central problem of “what to produce” and “for whom to produce”. Why do these problems arise at all?
Show Answer
Why these problems arise (2 marks). Human wants are unlimited, while the resources available to satisfy them are scarce and have alternative uses. Because of this, no economy can produce everything its people want. It is compelled to choose, and these choices take the form of the central problems.
What to produce and in what quantities (2 marks). An economy must decide which goods to produce with its limited resources and in what quantities. At a broad level it must decide how much of its resources to devote to consumer goods and how much to capital goods; within each group it must decide, say, how much wheat and how much sugarcane. The problem arises because devoting resources to one good necessarily means fewer resources for another. The economy should select the combination that yields the maximum satisfaction to society, and the choice can be illustrated by choosing a point on the production possibility curve.
For whom to produce (2 marks). Since the output produced is limited, the economy must decide how it will be distributed among the people — that is, who gets how much. In a market economy this is settled largely by the incomes people earn from the factors they own: wages for labour, rent for land, interest for capital and profit for enterprise. This raises the further question of equity, since a distribution determined purely by ownership may leave some sections with too little. Governments therefore often intervene through taxation, subsidies and welfare programmes to modify the outcome.
Conclusion. Both problems would vanish if resources were unlimited, since then everything could be produced in whatever quantity and everyone could have as much as they wished.
Q9 (4 marks). State with reason the effect on an economy’s PPC for wheat and cloth of each of the following: (a) discovery of a large new coalfield; (b) a new irrigation technique that raises only wheat yields; (c) a decision to shift some land from wheat to cotton for cloth; (d) a severe epidemic that reduces the working population.
Show Answer
(a) Shifts outward (rightward). The economy’s stock of resources has increased, and energy from coal can be used in producing both wheat and cloth. Both intercepts move outward — this is economic growth.
(b) Rotates outward about the cloth intercept. Only wheat productivity improves, so maximum wheat output rises while maximum cloth output remains exactly as before. The new curve therefore meets the old one at the cloth intercept.
(c) No shift — a movement along the existing PPC. Neither resources nor technology has changed; only the allocation of existing resources between the two goods has changed. This movement carries an opportunity cost in terms of wheat forgone.
(d) Shifts inward (leftward). Labour is a resource used in producing both goods, so a fall in the working population reduces the economy’s productive capacity for both. Both intercepts move inward.
Method. For each part, first ask whether resources or technology changed. If not, it is a movement along. If yes, ask whether both goods or only one is affected: both → parallel shift, one → rotation.
Q10 (6 marks). Why is the production possibility curve (i) downward sloping and (ii) concave to the origin? Also explain what it means when an economy is producing at a point inside the curve, and whether moving from that point to the curve involves any opportunity cost.
Show Answer
(i) Downward sloping (1.5 marks). The PPC is drawn on the assumption that resources are fixed and fully employed. Therefore production of one good can be increased only by transferring resources away from the other good, which reduces its output. Since more of one good always means less of the other, the curve must slope downward from left to right.
(ii) Concave to the origin (2 marks). Concavity follows from the law of increasing marginal opportunity cost. Resources are not equally efficient in producing both goods. When the economy begins producing more of Good X, it first transfers those resources that are best suited to X and least suited to Y, so the sacrifice of Y is small. As it produces still more X, it must transfer resources that were increasingly well suited to Y, so each additional unit of X costs more and more units of Y. The marginal rate of transformation therefore rises, the slope of the curve becomes steeper, and the curve takes a shape that is concave to the origin.
Meaning of a point inside the curve (1.5 marks). A point inside the PPC shows that the economy’s resources are not being fully or efficiently utilised. There is unemployment of resources or their inefficient use, so the economy is producing less of both goods than it is capable of producing. Such a point is attainable but wasteful.
Opportunity cost of moving on to the curve (1 mark). This movement involves no opportunity cost. The additional output is obtained by employing resources that were previously idle, so nothing has to be sacrificed. Opportunity cost arises only once the economy is already on the curve, because from that point onwards more of one good can be obtained only by giving up some of the other.
One Last Thing Before You Close This Page
If some of this still feels slippery, that is completely normal on day one. Nobody understands opportunity cost and the concave PPC in a single sitting. Go back tomorrow, redraw the Sunrise Sports curve from memory, and see how far you get before you have to peek. The day after, try the worksheet again without the answer boxes.
That is the whole method, and it is the Japanese idea of kaizen — small, steady, unglamorous improvement. You do not need a heroic six-hour session. You need to be slightly better than you were yesterday, every day, for a few months. So here is your only target: aim for one more correct question than yesterday. Do that from April, and by the time the exam arrives you will wonder what you were ever worried about. See you in the next chapter.