UPSC Mains 2023 Economics Optional Question Papers with Model Answers

All 56 questions of the 2023 Civil Services Main Examination, Economics Paper I and Economics Paper II, with marks and a suggested time per part. Solve each part on paper first, then open the model answer, or send it to answer-writing practice for evaluation.

UPSC Mains 2023 Economics Paper I

Question 1 (50 marks)

Q1(a) · Market Structures · 10 marks≈ 7 min
Perfect Competition and Monopoly: The Benchmarks
Examine the role of price elasticity of demand in determining the price set by a discriminating monopolist.
हिंदी में प्रश्न
एक विभेदात्मक एकाधिकारी द्वारा कीमत-निर्धारण में माँग की कीमत-लोच की भूमिका का परीक्षण कीजिए।
Practise this question Market Structures notes
Model answer
Paper and question: Paper I, Q1(a)
Approach: State the profit-maximising condition for third-degree discrimination, derive the inverse-elasticity pricing rule, and show that the less elastic market gets the higher price.
Price discrimination (Pigou, The Economics of Welfare, 1920) means selling the same product at different prices to different buyers for reasons not related to cost. In third-degree discrimination the monopolist divides buyers into markets that cannot resell to each other.
Condition: profit is maximised where MR₁ = MR₂ = MC: if MR were higher in one market, shifting a unit there would raise revenue.
Role of elasticity: since MR = P(1 − 1/e), the condition gives P₁(1 − 1/e₁) = P₂(1 − 1/e₂). Hence P₁/P₂ = (1 − 1/e₂)/(1 − 1/e₁), so the market with the lower elasticity gets the higher price. If elasticities are equal, discrimination is not profitable. Equivalently, the mark-up rule (P − MC)/P = 1/e holds in each market.
Diagram: three panels: market 1 with steep (inelastic) D₁ and MR₁, market 2 with flatter D₂ and MR₂, and the aggregate ΣMR cutting MC at total output; a horizontal line from that point gives q₁ and q₂ where MR₁ and MR₂ equal MC, with P₁ above P₂.
Examples: Indian Railways' class-wise fares, student discounts and airline fares by booking time; telecom plans for different users. Elasticity is thus the key that decides both whether to discriminate and how much.
Q1(b) · Price Determination and Theories of Distribution · 10 marks≈ 7 min
Consumer, Production and Cost Theory: Foundations
Explain the backward bending supply curve of labour as a choice between income and leisure.
हिंदी में प्रश्न
आय एवं अवकाश के बीच चुनाव के सन्दर्भ में, पीछे की ओर झुके हुए श्रम के पूर्ति वक्र की व्याख्या कीजिए।
Practise this question Price Determination and Theories of Distribution notes
Model answer
Paper and question: Paper I, Q1(b)
Approach: Set up the income-leisure choice with the budget line, split a wage rise into substitution and income effects, and show how the income effect dominates at high wages to give the backward bend.
A worker divides time T between leisure L and work T − L, maximising U(Y, L) subject to Y = w·(T − L) + V; the wage w is the price of leisure.
Equilibrium: the MRS of leisure for income equals w.
Effect of a wage rise: (i) substitution effect: leisure becomes costlier, so the worker substitutes work for leisure and hours rise; (ii) income effect: the worker is richer and, leisure being a normal good, buys more leisure, so hours fall.
At low wages the substitution effect dominates and labour supply rises with w. Beyond some wage the income effect dominates (the worker already has a comfortable income and values free time more), so hours fall as w rises: the labour supply curve bends backward.
Diagram: leisure on the horizontal axis (0 to T) and income on the vertical; budget lines pivot upward from T as w rises; tangency points trace a wage-offer curve that first moves left (more work) then right (less work); plotting w against hours worked (T − L) gives a curve that rises and then bends back.
Examples: working hours fell in rich countries as real wages rose; the bend applies to individuals, while market supply may still slope upward as new workers enter.
Q1(c) · Theories of Employment, Income and Interest · 10 marks≈ 7 min
Keynesian Theory of Income and Employment
Explain the major differences between classical and Keynesian macroeconomics.
हिंदी में प्रश्न
प्रतिष्ठित एवं केन्ज़ीय समष्टि अर्थशास्त्र की प्रमुख भिन्नताओं की व्याख्या कीजिए।
Practise this question Theories of Employment, Income and Interest notes
Model answer
Paper and question: Paper I, Q1(c)
Approach: Contrast the two schools point by point: Say's law versus effective demand, wage-price flexibility, saving-investment and interest, money, equilibrium, time horizon and policy.
(i) Demand: classical economists accept Say's law, supply creates its own demand; Keynes holds that output is determined by effective demand. (ii) Wages and prices: flexible in the classical system, so markets clear; rigid downwards (especially money wages) for Keynes. (iii) Equilibrium: always at full employment for the classics; for Keynes an underemployment equilibrium is possible, with involuntary unemployment.
(iv) Saving and investment: equated by the interest rate in the classical theory; by changes in income in Keynes, with interest determined by liquidity preference and the money supply.
(v) Money: neutral in the classical dichotomy (quantity theory); in Keynes money affects output through the interest rate. (vi) AS curve: vertical for the classics, horizontal or upward-sloping for Keynes in the short run.
(vii) Time horizon and policy: classical analysis is long-run and favours laissez-faire and balanced budgets; Keynes focused on the short run ('in the long run we are all dead', A Tract on Monetary Reform, 1923) and advocated active fiscal policy.
Q1(d) · Theories of Employment, Income and Interest · 10 marks≈ 7 min
Investment, Business Cycles and Aggregate Demand–Supply
What is meant by internal rate of return in the theory of investment? What is its importance in deciding whether to accept investment project?
हिंदी में प्रश्न
निवेश-सिद्धान्त के अन्तर्गत आन्तरिक-प्रतिफल-दर का क्या अर्थ है? किसी निवेश परियोजना को स्वीकार करना है, यह निर्णय लेने में इसका क्या महत्व है?
Practise this question Theories of Employment, Income and Interest notes
Model answer
Paper and question: Paper I, Q1(d)
Approach: Define IRR as the discount rate that makes the present value of returns equal the cost (Keynes' marginal efficiency of capital), give the formula and decision rule (accept if IRR exceeds the cost of capital), and compare with NPV.
The internal rate of return (IRR) of an investment project is the discount rate that makes the present value of its expected net returns equal to its cost. Keynes called the same concept the marginal efficiency of capital (General Theory, 1936).
Formula: for a project costing C that yields returns R₁, R₂, …, Rₙ, the IRR is the rate ρ that solves C = R₁/(1 + ρ) + R₂/(1 + ρ)² + … + Rₙ/(1 + ρ)ⁿ. Example: a machine costing ₹100 that yields ₹110 after one year has IRR = 10 per cent.
Decision rule: accept the project if its IRR exceeds the market rate of interest or the firm's cost of capital, since it then earns more than the cost of financing; reject it if lower. Ranking projects by IRR and investing until the IRR of the marginal project equals the interest rate gives the investment demand schedule.
Diagram: interest rate on the vertical and investment on the horizontal axis; a downward MEC curve; investment I₀ where MEC equals the market rate r₀.
Q1(e) · Money and Monetary Management · 10 marks≈ 7 min
Goals and Instruments of Monetary Policy in Closed and Open Economies
Explain why it is considered difficult for open market operations to affect both the availability and cost of credit at the same time.
हिंदी में प्रश्न
समझाइए कि खुले बाजार की क्रियाओं के द्वारा साख की उपलब्धता एवं लागत दोनों को एक ही समय पर प्रभावित करना क्यों कठिन माना जाता है?
Practise this question Money and Monetary Management notes
Model answer
Paper and question: Paper I, Q1(e)
Approach: Explain that OMOs work on the supply of reserves against a given demand, so the central bank can fix either the quantity of reserves (availability) or the interest rate (cost), not both independently; add Poole's instrument choice and the effect of shifting demand.
Open market operations are the central bank's purchases and sales of government securities, which change the reserves of banks.
The difficulty: the demand for reserves (and for money and credit) slopes downward against the interest rate and is set by banks and the public. Through OMOs the central bank controls only the supply. It can therefore choose a point on the demand curve: either a quantity of reserves and credit (availability), letting the interest rate settle where demand meets supply; or an interest rate (cost), supplying whatever quantity is demanded at that rate. It cannot independently fix both.
Shifting demand: if credit demand rises in a boom, holding the quantity fixed makes rates rise, while holding the rate fixed requires OMO purchases that expand availability. Poole (1970) showed that the better target depends on whether shocks come mainly from the money market or the goods market.
Diagram: interest rate against reserves; a downward demand curve D₁ shifting to D₂; a vertical supply (quantity target) gives a higher rate, a horizontal supply (rate target) gives a larger quantity.
RBI, like most central banks, now targets the cost (the repo rate) and uses OMOs to manage liquidity around it.

Question 2 (50 marks)

Q2(a) · Market Structures · 20 marks≈ 14 min
Duopoly Models: Cournot, Bertrand, Stackelberg and Edgeworth
Explain the Cournot model of duopoly using reaction functions and interpret it as a Nash equilibrium.
हिंदी में प्रश्न
प्रतिक्रिया फलनों का प्रयोग करते हुए कूर्नो के द्वयधिकार मॉडल की व्याख्या कीजिए तथा इसका नैश-सन्तुलन के रूप में निर्वचन कीजिए।
Practise this question Market Structures notes
Model answer
Paper and question: Paper I, Q2(a)
Approach: State Cournot's assumptions, derive the reaction functions with a linear example, solve for equilibrium, show the reaction-curve diagram, and explain why the solution is a Nash equilibrium; end with stability and criticism.
Augustin Cournot (Recherches sur les principes mathématiques de la théorie des richesses, 1838) analysed two sellers of a homogeneous product (his example was mineral water) who choose quantities.
Assumptions: two firms, identical product, linear market demand P = a − b(q₁ + q₂), constant marginal cost c; each firm chooses its output assuming the rival's output stays unchanged (zero conjectural variation, dq₂/dq₁ = 0); decisions are simultaneous.
Reaction functions: firm 1 maximises π₁ = [a − b(q₁ + q₂)]q₁ − cq₁. The first-order condition a − 2bq₁ − bq₂ − c = 0 gives q₁ = (a − c)/2b − q₂/2. Symmetrically, q₂ = (a − c)/2b − q₁/2. Each reaction function gives a firm's best output for every output of the rival.
Equilibrium: solving together, q₁ = q₂ = (a − c)/3b, total output 2(a − c)/3b and P = (a + 2c)/3: more than monopoly output (a − c)/2b but only two-thirds of competitive output (a − c)/b.
Diagram: q₁ on the horizontal and q₂ on the vertical axis; two downward-sloping reaction lines, R₁ steeper (intercepts (a − c)/2b on the q₁ axis and (a − c)/b on the q₂ axis) and R₂ flatter; they cross at the Cournot point E; arrows from any starting point converge to E.
Nash interpretation: a Nash equilibrium (Nash, 1950) is a set of strategies in which each is a best response to the others. At E each firm's output lies on its reaction function, so neither can gain by changing output unilaterally: the Cournot solution is the Nash equilibrium in quantities, and the conjecture that the rival's output is fixed is fulfilled in equilibrium.
Stability: with linear demand the equilibrium is stable because R₁ is steeper than R₂ in (q₁, q₂) space.
Criticism: the zero conjecture is naive outside equilibrium, and Bertrand (1883) argued firms set prices; Kreps and Scheinkman (1983) showed that capacity choice followed by price competition yields the Cournot outcome.
Q2(b) · Market Structures · 15 marks≈ 11 min
Perfect Competition and Monopoly: The Benchmarks
"Perfect competition is incompatible with increasing returns to scale." Examine the statement.
हिंदी में प्रश्न
"पूर्ण-प्रतियोगिता, पैमाने के बढ़ते प्रतिफल के साथ असंगत है।" इस कथन का परीक्षण कीजिए।
Practise this question Market Structures notes
Model answer
Paper and question: Paper I, Q2(b)
Approach: Explain why increasing returns make marginal cost lie below average cost, so that price = MC gives losses and firms grow until competition breaks down; add Sraffa's critique and the ways out (external economies, Marshall).
Perfect competition requires many price-taking firms, each producing where P = MC with MC rising. Increasing returns to scale mean that a proportionate rise in all inputs raises output more than proportionately, so long-run average cost (LAC) falls as output grows.
Incompatibility: (i) with falling LAC, LMC lies below LAC, so a price equal to MC is below average cost and every firm makes a loss; the P = MC equilibrium cannot be sustained. (ii) If price exceeds the cost of a larger firm, each firm gains by expanding, since unit cost keeps falling; the second-order condition fails. (iii) Firms grow until they are large relative to the market and stop being price takers: competition gives way to oligopoly or natural monopoly.
Sraffa's critique ('The Laws of Returns under Competitive Conditions', Economic Journal, 1926) pressed exactly this point: internal economies of scale are inconsistent with competitive equilibrium, so firms are limited by demand, not cost, which pointed towards imperfect competition theory (Joan Robinson, 1933; Chamberlin, 1933).
Reconciliation: Marshall's external economies lower the industry's supply curve while each firm still faces rising costs, so decreasing-cost industries can be competitive.
Diagram: output on the horizontal and cost on the vertical axis; a falling LAC with LMC below it; a horizontal price line P = LMC at q₀ lies below LAC, showing a loss per unit equal to the gap.
Examples: power transmission, railways and telecom networks are natural monopolies regulated by bodies such as CERC and TRAI. The statement holds for internal, not external, economies of scale.
Q2(c) · Market Structures · 15 marks≈ 11 min
Oligopoly: Kinked Demand, Collusion, Price Leadership and Game Theory
Describe a model of oligopoly that explains price stickiness.
हिंदी में प्रश्न
अल्पाधिकार के एक ऐसे मॉडल की व्याख्या कीजिए जो निश्चल-कीमत की व्याख्या करता है।
Practise this question Market Structures notes
Model answer
Paper and question: Paper I, Q2(c)
Approach: Present Sweezy's kinked demand curve model: asymmetric conjecture, kink, discontinuous MR, and why MC can shift within the gap without changing price; add criticism.
Price stickiness in oligopoly, observed by Hall and Hitch (1939) in their survey of British firms, is explained by the kinked demand curve model of Paul Sweezy ('Demand under Conditions of Oligopoly', Journal of Political Economy, 1939).
Assumption (asymmetric conjecture): each oligopolist believes that if it raises its price, rivals will not follow, so it loses many customers; but if it cuts its price, rivals will match the cut, so it gains few. Demand is therefore elastic above the current price and inelastic below it, producing a kink at the prevailing price P*.
Discontinuous MR: the marginal revenue curve corresponding to the elastic upper segment and that of the inelastic lower segment do not meet: at the kinked output Q*, MR drops vertically, creating a gap.
Price rigidity: profit is maximised where MC passes through the gap. If marginal cost rises or falls within the gap (MC₁ to MC₂), the MR = MC output and the price stay at Q* and P*. Moderate shifts in demand that keep the kink at the same price also leave price unchanged. Firms therefore prefer non-price competition (advertising, quality).
Diagram: price on the vertical and quantity on the horizontal axis; a demand curve dKD, flatter above the kink K and steeper below it; the MR curve with a vertical gap AB below K; MC₁ and MC₂ both passing through AB, giving the same Q* and P*.
Criticism: the model explains why price stays at P* but not how P* is set; Stigler (1947) found little evidence of the asymmetric reaction; and in inflation all firms raise prices together, removing the kink.

Question 3 (50 marks)

Q3(a) · Theories of Employment, Income and Interest · 20 marks≈ 14 min
New Classical and New Keynesian Macroeconomics
"Under rational expectation hypothesis, systematic monetary policy is ineffective." Explain the above statement using a suitable model.
हिंदी में प्रश्न
"तार्किक प्रत्याशा-परिकल्पना के अन्तर्गत, नियमित मौद्रिक नीति निष्प्रभावी होती है।" एक उचित मॉडल के द्वारा उपर्युक्त कथन की व्याख्या कीजिए।
Practise this question Theories of Employment, Income and Interest notes
Model answer
Paper and question: Paper I, Q3(a)
Approach: Use a log-linear model (Lucas supply, quantity-theory AD and a feedback money rule), solve for expected and actual prices under rational expectations, and show the rule parameter drops out of the output equation; interpret and criticise.
The statement is the policy ineffectiveness proposition of Sargent and Wallace (1975), built on Muth's rational expectations hypothesis (1961) and Lucas's supply function (1972).
Model (variables in logs): supply yₜ = yn + β(pₜ − Eₜ₋₁pₜ) + uₜ; demand yₜ = mₜ − pₜ + vₜ (quantity theory with velocity shocks); policy rule mₜ = m̄ + γ(yₜ₋₁ − yn) + εₜ, where γ is the systematic (feedback) response and εₜ an unpredictable money shock; u, v, ε are random with zero mean.
Step 1: equating supply and demand: (1 + β)pₜ = mₜ + vₜ − yn + βEₜ₋₁pₜ − uₜ.
Step 2: taking expectations at t − 1 (expected shocks are zero): Eₜ₋₁pₜ = Eₜ₋₁mₜ − yn, where Eₜ₋₁mₜ = m̄ + γ(yₜ₋₁ − yn), since the rule is known.
Price surprise: subtracting, pₜ − Eₜ₋₁pₜ = (mₜ − Eₜ₋₁mₜ + vₜ − uₜ)/(1 + β) = (εₜ + vₜ − uₜ)/(1 + β).
Step 4: substituting in the supply function, yₜ = yn + [βεₜ + βvₜ + uₜ]/(1 + β).
Result: output depends only on the natural level and on unpredictable shocks; the policy parameter γ does not appear. Whatever systematic feedback rule the central bank chooses, agents build it into their price expectations, so it changes the price level but not output. Only the money surprise εₜ affects output, and a central bank cannot use surprises systematically, because a systematic surprise would be learned and anticipated.
Diagram: (y, p) space with a vertical long-run supply at yn and an upward short-run supply drawn for a given expected price; an anticipated AD shift shifts the short-run supply up equally, leaving y at yn.
Criticism: the result needs flexible prices; with overlapping wage contracts (Fischer, 1977; Taylor, 1980) systematic policy can stabilise output even under rational expectations. Information lags, learning and credibility problems also matter. Yet the proposition, with the Lucas critique (1976), forced economists to model expectations explicitly and underlies the emphasis on rule-based, credible policy such as inflation targeting.
Q3(b) · Theories of Employment, Income and Interest · 15 marks≈ 11 min
IS-LM Model and the Neo-classical Synthesis
In the IS-LM framework, the effectiveness of monetary and fiscal policies depend on the interest elasticity of investment. Explain.
हिंदी में प्रश्न
IS-LM ढांचे के अन्तर्गत मौद्रिक एवं राजकोषीय नीतियों की प्रभावशीलता, निवेश की ब्याज-लोच पर निर्भर करती है। समझाइए।
Practise this question Theories of Employment, Income and Interest notes
Model answer
Paper and question: Paper I, Q3(b)
Approach: Relate the slope of IS to the interest elasticity of investment, then show with IS-LM diagrams that high elasticity strengthens monetary policy and weakens fiscal policy (large crowding out), and low elasticity the reverse.
In the IS-LM model the slope of the IS curve is dr/dY = −[1 − c(1 − t)]/b, where b measures the response of investment to the interest rate. A high interest elasticity of investment gives a flat IS; a low one gives a steep IS (vertical if investment ignores the interest rate).
Monetary policy: an increase in the money supply shifts LM to the right and lowers the interest rate. Its effect on income works entirely through investment. If investment is highly interest-elastic (flat IS), the fall in r raises investment sharply and income rises a lot. If investment is inelastic (steep IS), the interest rate falls but investment and income hardly change: monetary policy is weak, as in a slump when expectations are poor.
Fiscal policy: a rise in G shifts IS right; higher income raises money demand and the interest rate. If investment is highly interest-elastic, the rise in r chokes off much private investment (large crowding out), so income rises little. If investment is inelastic, crowding out is small and fiscal policy is powerful; with a vertical IS it is fully effective.
Diagram: two panels with the same LM shift (LM₁ to LM₂) and the same IS shift (by ΔG times the multiplier); with a flat IS the monetary shift gives a large ΔY and the fiscal shift a small ΔY; with a steep IS the opposite.
Formally: the fiscal multiplier 1/[s + bk/h] falls as b rises, and the monetary multiplier (b/h)/[s + bk/h] rises with b.
Q3(c) · Theories of Employment, Income and Interest · 15 marks≈ 11 min
Keynesian Theory of Income and Employment
How important is speculative demand for money in achieving unemployment equilibrium in the Keynesian model? Discuss.
हिंदी में प्रश्न
केन्ज़ीय मॉडल के अन्तर्गत, बेरोजगारी-संतुलन प्राप्त करने में मुद्रा की सट्टा-जनित मांग का क्या महत्व है? चर्चा कीजिए।
Practise this question Theories of Employment, Income and Interest notes
Model answer
Paper and question: Paper I, Q3(c)
Approach: Explain how speculative demand produces the liquidity trap that blocks the interest-rate route to full employment, then assess its importance: unemployment can also arise from interest-inelastic investment or rigid wages, and the Pigou effect challenges the trap.
Keynes (1936) divided the demand for money into transactions, precautionary and speculative motives. Speculative demand arises because people expect interest rates to return to a 'normal' level: when the rate is low, bond prices are high and expected to fall, so wealth holders prefer money. Speculative demand is therefore inversely related to the interest rate.
Role in unemployment equilibrium: in the classical view, unemployment lowers wages and prices, raises real money balances and lowers the interest rate, which raises investment until full employment is restored (the Keynes effect). Speculative demand can break this chain: at a very low rate everyone expects bond prices to fall, demand for money becomes perfectly elastic (the liquidity trap), and extra real balances are hoarded instead of lowering the interest rate. Investment then cannot rise to equal full-employment saving, and the economy remains at an unemployment equilibrium.
Diagram: IS-LM with an LM curve horizontal at the trap rate r_min; IS cuts LM in the flat part at Ye less than Yf; an increase in real money balances shifts the vertical part of LM right but leaves equilibrium unchanged.
How important? (i) It is not necessary: unemployment equilibrium also arises if investment is interest-inelastic (a steep IS that cuts the income axis below Yf at any positive rate) or if money wages are rigid (Modigliani, 1944). (ii) It is not sufficient: even in a trap, falling prices raise real wealth and consumption through the Pigou effect, shifting IS right. (iii) Empirically, a pure trap is rare; Japan in the 1990s and advanced economies after 2008, at the zero lower bound, came closest.

Question 4 (50 marks)

Q4(a) · Balance of Payments and Exchange Rates · 20 marks≈ 14 min
Balance of Payments Adjustment: Elasticity, Absorption and Monetary Approaches
Explain the concept of "sterilization" in the context of monetary approach to balance of payments.
हिंदी में प्रश्न
भुगतान-सन्तुलन के मौद्रिक दृष्टिकोण के संदर्भ में, "स्टरिलाइज़ेशन" की अवधारणा की व्याख्या कीजए।
Practise this question Balance of Payments and Exchange Rates notes
Model answer
Paper and question: Paper I, Q4(a)
Approach: Set out the monetary approach (money supply H = D + R, BoP as a monetary phenomenon, automatic adjustment), define sterilisation and show how it blocks adjustment, with India's experience (MSS 2004) and limits.
The monetary approach to the balance of payments (Harry Johnson, Robert Mundell, Jacob Frenkel, 1970s) treats the BoP as a monetary phenomenon: a surplus or deficit reflects an imbalance between the demand for and the supply of money. The monetary base is H = D + R, where D is domestic credit of the central bank and R is foreign exchange reserves.
Automatic adjustment under fixed rates: if domestic credit expands faster than money demand, people spend the excess money on foreign goods and assets, creating a BoP deficit. The central bank sells reserves to defend the peg, so R and the money supply fall until money supply again equals money demand and the deficit disappears. The BoP is thus self-correcting: ΔR = ΔMd − ΔD.
Sterilisation is the action of the central bank to offset the effect of reserve changes on the monetary base. With a surplus, reserves rise and the bank sells government securities (open market operations) to reduce domestic credit by the same amount, so H stays unchanged; with a deficit, it buys securities to replace the lost reserves.
Consequence: sterilisation blocks the automatic adjustment mechanism: the money supply does not change, so the imbalance persists and reserves keep changing.
India: during the large capital inflows of 2003–08 the RBI bought dollars and sterilised through open market sales and the Market Stabilisation Scheme (introduced in 2004), under which government securities were issued to absorb liquidity. The costs were the interest on these securities, and upward pressure on domestic interest rates, which attracts more inflows.
Hence sterilisation lets a central bank control domestic money and inflation in the short run, but it cannot prevent the adjustment that the monetary approach predicts in the long run.
Q4(b) · Public Finance · 15 marks≈ 11 min
Taxation: Sources of Revenue, Forms, Incidence and Effects
Tax burden is distributed between buyers and sellers in the ratio of elasticities of demand and supply. Explain.
हिंदी में प्रश्न
क्रेताओं और विक्रेताओं के मध्य कर-भार माँग और पूर्ति लोचों के अनुपात में वितरित होता है। व्याख्या कीजिए।
Practise this question Public Finance notes
Model answer
Paper and question: Paper I, Q4(b)
Approach: Derive the incidence rule with the tax wedge (Δ prices in terms of elasticities), draw the diagram and illustrate the extreme cases.
The legal (impact) incidence of a tax falls on whoever pays it to the government, but its economic (effective) incidence depends on how prices adjust. In a competitive market the burden is shared in inverse proportion to the price elasticities: the more inelastic side bears more.
Let a small specific tax t be imposed. The buyer's price rises by ΔPd and the seller's price falls by ΔPs, with ΔPd + ΔPs = t. For the market to clear, the fall in quantity demanded must equal the fall in quantity supplied: Ed × (ΔPd/P) = Es × (ΔPs/P), where Ed is the absolute demand elasticity and Es the supply elasticity.
Hence ΔPd/ΔPs = Es/Ed, i.e. buyers' share/sellers' share = Es/Ed. Equivalently the buyers' share of the tax is Es/(Es + Ed) and the sellers' share is Ed/(Es + Ed). This rule goes back to Marshall's and Dalton's analysis of tax shifting.
Diagram: demand D and supply S in (Q, P) space with equilibrium E at P₀, Q₀; the tax shifts S up by t to S + t; new quantity Q₁; buyers pay P₁ above P₀ and sellers receive P₁ − t below P₀; the rectangle above P₀ is the buyers' burden and the one below is the sellers' burden; the triangle between is the deadweight loss.
Extreme cases: perfectly inelastic demand (Ed = 0) or perfectly elastic supply puts the whole burden on buyers; perfectly inelastic supply (land, Henry George's argument) or perfectly elastic demand puts it on sellers. Examples: excise on tobacco and petrol, whose demand is inelastic, falls mainly on consumers, while a tax on one brand among many close substitutes falls mainly on producers.
The rule holds for partial equilibrium and small taxes; in the long run supply is more elastic, so a larger share shifts to buyers.
Q4(c) · Money and Monetary Management · 15 marks≈ 11 min
Quantity Theories of Money: Fisher, Cambridge (Pigou) and Friedman
Discuss Friedman's restatement of Quantity Theory of Money. Under what conditions, it reduces to classical Quantity Theory of Money? Explain.
हिंदी में प्रश्न
फ्रीडमैन के मुद्रा-परिमाण-सिद्धान्त के पुनर्कथन की विवेचना कीजिए। यह किन दशाओं में, प्रतिष्ठित मुद्रा-परिमाण-सिद्धान्त में परिवर्तित हो जाता है? समझाइये।
Practise this question Money and Monetary Management notes
Model answer
Paper and question: Paper I, Q4(c)
Approach: Set out Friedman's restatement (money demand function and its properties), then state the conditions under which it collapses to MV = PY with P proportional to M.
Restatement: Friedman (1956) recast the quantity theory as a theory of the demand for money, an asset among bonds, equities and goods: M/P = f(yₚ, w, r_b, r_e, πᵉ, u), depending on permanent income, the wealth ratio, asset yields, expected inflation and tastes.
Properties: the function is homogeneous of degree one in prices and income (no money illusion); it is stable; its interest elasticity is low; hence velocity V = Y/f(·) is a stable, predictable function of a few variables rather than a constant.
Transmission: if the money supply rises, people hold excess balances and spend them on a wide range of assets and goods, raising nominal income until money demand equals the new supply.
Reduction to the classical theory: the restatement yields MV = PY with P proportional to M when (i) velocity is constant, i.e. the interest rates and expected inflation in the demand function do not change, or money demand is interest-inelastic; (ii) real output Y is fixed at full employment by real factors (vertical AS), as in the long run; (iii) the money supply is exogenous, determined by the central bank independently of demand. Then a doubling of M doubles nominal income, all of it as prices.
Diagram: (Y, P) space with a vertical long-run AS at Yf; a rise in M shifts AD (MV = PY) outward and raises only P.

Question 5 (50 marks)

Q5(a) · Theories of International Trade · 10 marks≈ 7 min
Comparative Advantage: Ricardo and Heckscher-Ohlin
"Factor intensity reversal is incompatible with Heckscher-Ohlin model." Examine this statement.
हिंदी में प्रश्न
"कारक तीव्रता उत्क्रमण हेक्शचर-ओहलिन मॉडल से असंगत है।" इस कथन का परीक्षण कीजिए।
Practise this question Theories of International Trade notes
Model answer
Paper and question: Paper I, Q5(a)
Approach: Define factor intensity reversal, show with isoquants why it arises (different elasticities of substitution), explain why it invalidates the H-O theorem for one country, and cite Minhas and Leontief.
Factor intensity reversal occurs when a good is capital-intensive at one set of factor prices and labour-intensive at another. It arises when the elasticities of substitution between capital and labour differ between the two industries, so their isoquants cross twice.
Diagram: unit isoquants of X and Y in (L, K) space crossing at two points; at a low wage-rental ratio X is labour-intensive, at a high ratio X is capital-intensive.
The statement is correct. H-O requires that goods can be ranked by factor intensity at all factor prices. With a reversal, suppose X is labour-intensive in labour-abundant India (low w/r) but capital-intensive in the capital-abundant US (high w/r). H-O predicts that India exports X and that the US exports X too, which is impossible: both cannot export the same good to each other. So the theorem fails for one country, and factor-price equalisation also breaks down.
Empirically, Minhas (1962) found frequent reversals using CES production functions, but Leontief (1964) showed that most disappeared when a few natural-resource industries were excluded; reversals are therefore possible but not common.
Q5(b) · Balance of Payments and Exchange Rates · 10 marks≈ 7 min
Exchange Rate Regimes: Fixed, Floating, Currency Boards and Developing Countries
Why depreciation of a currency is inflationary? Explain.
हिंदी में प्रश्न
किसी करेंसी का मूल्यह्रास स्फीतिक क्यों होता है? समझाइए।
Practise this question Balance of Payments and Exchange Rates notes
Model answer
Paper and question: Paper I, Q5(b)
Approach: Explain the channels through which depreciation raises the price level (import prices and pass-through, input costs, demand for exports, wages and expectations), with India's oil example and the conditions affecting pass-through.
Depreciation raises the domestic-currency price of foreign currency, and it is inflationary through several channels.
(i) Direct effect: imported consumer goods become dearer in domestic currency; the extent depends on the exchange-rate pass-through. (ii) Cost-push: imported inputs such as crude oil, fertilisers, electronics components and machinery become costlier, raising production costs across the economy; in India, which imports over 85% of its crude oil, a weaker rupee raises fuel and transport costs. (iii) Demand-pull: cheaper exports and costlier imports switch demand towards domestic goods, raising aggregate demand and prices if capacity is limited.
(iv) Wages and expectations: higher living costs lead to wage demands and higher inflation expectations, creating a price-wage spiral.
Pass-through is larger in open, import-dependent economies with weak monetary credibility, and smaller when the depreciation is seen as temporary or when inflation expectations are anchored, as under the RBI's inflation-targeting framework since 2016.
Q5(c) · Economic Development · 10 marks≈ 7 min
Development and Environmental Sustainability
Can Kuznet's hypothesis of an inverted U-curve be extended to analyse environmental degradation? Explain.
हिंदी में प्रश्न
क्या कुज़नेट के एक उल्टे U-वक्र की परिकल्पना पर्यावरणीय अवक्रमण के विश्लेषण के लिये प्रयुक्त हो सकती है? व्याख्या कीजिए।
Practise this question Economic Development notes
Model answer
Paper and question: Paper I, Q5(c)
Approach: Explain the environmental Kuznets curve (Grossman and Krueger), its mechanisms (scale, composition, technique, demand for environment) and diagram, then the limits of the extension.
Yes, partly. Grossman and Krueger (1991, 1995) found that some pollutants rise with income per head at low levels and fall beyond a turning point, an inverted U named the environmental Kuznets curve (EKC) by Panayotou (1993).
Mechanisms: at first the scale effect of more output and industrialisation dominates; later the composition effect (shift to services) and the technique effect (cleaner technology) take over, and richer citizens demand a cleaner environment and stronger regulation, since environmental quality behaves like a normal or luxury good.
Diagram: pollution on the vertical axis and income per head on the horizontal; an inverted U with the peak at the turning-point income.
But the extension is limited: it holds for local pollutants such as sulphur dioxide, not for carbon dioxide or biodiversity loss; rich countries may export pollution through trade (pollution havens); damage may be irreversible before the turning point; and it reflects policy, not automatic growth. For carbon, emissions have kept rising with income in most countries.
Q5(d) · Economic Development · 10 marks≈ 7 min
Measuring Development: Human Development Indices and the Basic Needs Approach
Explain how modified HDI is an improved measure of development over HDI.
हिंदी में प्रश्न
समझाइए कि संशोधित एच.डी.आई. किस प्रकार एच.डी.आई. की अपेक्षा विकास की एक उन्नत माप है।
Practise this question Economic Development notes
Model answer
Paper and question: Paper I, Q5(d)
Approach: Explain the 2010 revision of the HDI (new indicators, geometric mean) and the inequality-adjusted HDI, showing how each improves on the original index.
The original HDI (1990) was a simple arithmetic average of indices of life expectancy, adult literacy with gross enrolment, and adjusted GDP per head. In 2010 UNDP introduced a modified HDI and companion indices.
Improvements: (i) better indicators: mean years and expected years of schooling replaced literacy and enrolment, which had reached ceilings in many countries, and GNI per head replaced GDP, since it measures the income residents actually receive; (ii) the geometric mean replaced the arithmetic mean, so poor performance in one dimension can no longer be fully offset by high achievement in another, and balanced development is rewarded.
(iii) The inequality-adjusted HDI (IHDI) discounts each dimension by its inequality across people (Atkinson measure), so the loss from inequality, the gap between HDI and IHDI, becomes visible; India loses roughly 30% of its HDI to inequality.
Later additions, such as the planetary pressures-adjusted HDI (2020), adjust for carbon emissions and material use. The modified HDI is thus a more accurate and more equity-sensitive measure, though weights and goalposts remain arbitrary.
Q5(e) · Economic Development · 10 marks≈ 7 min
Development and Environmental Sustainability
How renewable energy use can help attain environmental sustainability? Explain.
हिंदी में प्रश्न
नवीनीकरणीय ऊर्जा उपयोग किस प्रकार पर्यावरणीय पोषणीयता प्राप्त कराने में सहायक है? समझाइये।
Practise this question Economic Development notes
Model answer
Paper and question: Paper I, Q5(e)
Approach: Explain the channels through which renewable energy promotes environmental sustainability (emissions, local pollution, resource depletion, energy security), with Indian data and a caveat.
Renewable energy (solar, wind, hydro, biomass) comes from flows that are replenished naturally, unlike coal, oil and gas, which are finite stocks.
It supports environmental sustainability by: (i) cutting greenhouse gas emissions, since power and transport are the largest sources; (ii) reducing local air pollution from coal plants and vehicles, with large health gains; (iii) conserving non-renewable resources for future generations, in line with intergenerational equity; (iv) reducing water use in thermal power; and (v) improving energy security and reducing import dependence.
India targets 500 GW of non-fossil capacity by 2030 and net zero by 2070, and non-fossil sources reached about half of installed capacity in 2025; schemes include PM-KUSUM (2019) for solar pumps and the National Green Hydrogen Mission (2023).
Renewables need storage, grid upgrades and responsible land use and recycling of panels and batteries to be truly sustainable.

Question 6 (50 marks)

Q6(a) · Trade Policy, Protection and the WTO · 20 marks≈ 14 min
Tariffs and Quotas: Effects and Comparison
Consider the market for good X for Country 1 and Country 2. The supply and demand functions for Country 1 are given as P = Q + 70 and P = 170 − Q, while that of Country 2 are given as P = 10 + Q and P = 110 − Q. Assume that there are two countries in the world and trade is balanced. Free trade price is stabilized in between autarky prices of both the countries. Based on the above information, answer the following questions:
(i) From the free trade price and zero transportation cost, if the importing country imposes an import quota of 50 units, determine the quantity of good X produced and consumed. Calculate the consumer and producer surplus and protection cost due to import quota.
(ii) From the free trade price, assume that the importing country is small and consider an import tariff of Rs. 10 per unit on good X. Calculate the impact on consumer surplus, producer surplus and government revenue. Does this policy increase national welfare?
हिंदी में प्रश्न
वस्तु X का बाजार देश 1 तथा देश 2 में है। देश 1 में पूर्ति व माँग फलन क्रमशः P = Q + 70 तथा P = 170 − Q हैं जब कि देश 2 में पूर्ति व माँग फलन क्रमशः P = 10 + Q तथा P = 110 − Q हैं। मान लीजिए कि विश्व में केवल ये दो देश ही हैं तथा उनका व्यापार संतुलित है। स्वतन्त्र व्यापार कीमत दोनों देशों के व्यापार से पहले की कीमतों के मध्य स्थित होगी। उपर्युक्त सूचना को संज्ञान में लेते हुए, निम्न प्रश्नों का उत्तर दीजिए :
(i) स्वतन्त्र व्यापार कीमत एवं शून्य परिवहन लागत पर, यदि आयातक देश 50 इकाइयों का आयात-अभ्यंश लगाता है तो वस्तु X के उत्पादन एवं उपयोग की मात्रा ज्ञात कीजिए। आयात-अभ्यंश लगाने से उपभोक्ता अतिरेक, उत्पादक अतिरेक तथा संरक्षण लागत आगणित कीजिए।
(ii) यदि आयातक-देश छोटा है तथा स्वतन्त्र-व्यापार कीमत पर वस्तु X पर 10 रू. प्रति इकाई का प्रशुल्क लगाता है तो इसका प्रभाव उपभोक्ता-अतिरेक उत्पादक-अतिरेक तथा राजकीय-आगम पर ज्ञात कीजिए। क्या यह नीति राष्ट्रीय कल्याण में वृद्धि करती है?
Practise this question Trade Policy, Protection and the WTO notes
Model answer
Paper and question: Paper I, Q6(a)
Approach: Find autarky and free-trade equilibria from the two countries' curves, then solve (i) the quota case (domestic price, output, consumption, surpluses, deadweight loss and quota rent) and (ii) the small-country tariff case (changes in surpluses, revenue and net welfare), checking each step.
Write the functions as quantities. Country 1: Qs₁ = P − 70, Qd₁ = 170 − P. Country 2: Qs₂ = P − 10, Qd₂ = 110 − P.
Autarky: Country 1: P − 70 = 170 − P gives P = 120, Q = 50. Country 2: P − 10 = 110 − P gives P = 60, Q = 50. Country 1 has the higher price, so it imports and Country 2 exports.
Free trade: imports of Country 1 = 240 − 2P; exports of Country 2 = 2P − 120. Balanced trade: 240 − 2P = 2P − 120, so P = 90, between 60 and 120 as required. Trade = 60 units; Country 1 produces 20 and consumes 80. At P = 90, Country 1's consumer surplus = ½ × 80 × (170 − 90) = 3200 and producer surplus = ½ × 20 × (90 − 70) = 200.
Step 1 (quota of 50): 240 − 2P = 50 gives P = 95 in Country 1. Production = 95 − 70 = 25; consumption = 170 − 95 = 75 (imports 50). Consumer surplus = ½ × 75 × 75 = 2812.5 (a fall of 387.5); producer surplus = ½ × 25 × 25 = 312.5 (a rise of 112.5).
Step 2 (protection cost): production loss = ½ × (25 − 20) × (95 − 90) = 12.5; consumption loss = ½ × (80 − 75) × 5 = 12.5; total protection cost (deadweight loss) = 25. The quota rent at the free-trade price is (95 − 90) × 50 = 250. In the two-country world Country 2 must now export only 50, so its price falls to 85 (2P − 120 = 50), and the rent to licence holders rises to (95 − 85) × 50 = 500, of which 250 is a terms-of-trade gain from Country 2.
Step 3 (tariff of Rs 10, small importer): domestic price = 90 + 10 = 100. Production = 30, consumption = 70, imports = 40. Consumer surplus = ½ × 70 × 70 = 2450, a loss of 750. Producer surplus = ½ × 30 × 30 = 450, a gain of 250. Revenue = 10 × 40 = 400.
Step 4 (net welfare): −750 + 250 + 400 = −100, equal to the two deadweight triangles ½ × 10 × 10 + ½ × 10 × 10 = 50 + 50.
In words: the quota raises Country 1's price to 95, output to 25 and cuts consumption to 75, with a protection cost of 25; the tariff of Rs 10 lowers national welfare by Rs 100, because consumers lose more than producers and the government gain. For a small country, protection does not increase national welfare; only a large country can offset the loss through better terms of trade, as the quota case shows.
Q6(b) · Theories of International Trade · 15 marks≈ 11 min
Product Cycle, New Trade Theory and Strategic Trade Policy
"A continuous process of innovation and invention would give rise to trade even between countries with similar factor endowments and tastes." Examine the statement.
हिंदी में प्रश्न
"नवाचार व आविष्कार की सतत प्रक्रिया से उन देशों के बीच भी व्यापार प्रारम्भ हो जाता है जिनकी कारक निधियां तथा रुचियां समान हैं।" कथन का परीक्षण कीजिये।
Practise this question Theories of International Trade notes
Model answer
Paper and question: Paper I, Q6(b)
Approach: Examine with the technology-gap (Posner) and product-cycle (Vernon) theories and innovation-based new trade theory, showing why innovation generates trade between similar countries, then note limits.
The statement is valid. H-O theory needs differences in factor endowments (and Linder-type demand differences) to generate trade; with similar endowments and tastes it predicts little trade. Yet most world trade takes place between similar advanced economies, much of it driven by innovation.
Technology-gap theory (Michael Posner, 1961): a firm that innovates a new product or process enjoys a temporary monopoly and exports it until imitators abroad catch up. The trade lasts for the 'imitation lag' minus the 'demand lag'. If innovation is continuous, each country keeps generating new products and trade continues even between countries with similar endowments.
Product-cycle theory (Raymond Vernon, 1966): new products are developed in rich, innovative countries and exported; as they mature and standardise, production moves to other countries with lower costs. Continuous innovation keeps new goods flowing from innovators.
New trade theory: innovation creates differentiated varieties; with economies of scale each country specialises in different varieties, and consumers' love of variety creates two-way, intra-industry trade (Krugman, 1980). Endogenous growth models (Grossman and Helpman, 1991) link continuous R&D to this trade.
Examples: trade in pharmaceuticals, electronics and software between the US, Europe, Japan and Korea. However, innovation itself depends on human capital and R&D endowments, so the theories partly reflect 'technology endowments', and imitation now occurs faster, shortening gaps.
Q6(c) · Theories of International Trade · 15 marks≈ 11 min
Product Cycle, New Trade Theory and Strategic Trade Policy
Examine the significance of external economies and product variety in the context of international trade theory.
हिंदी में प्रश्न
अन्तर्राष्ट्रीय व्यापार सिद्धान्त के सन्दर्भ में, बाह्य मितव्ययिताओं तथा उत्पाद विविधता के महत्व का परीक्षण कीजिए।
Practise this question Theories of International Trade notes
Model answer
Paper and question: Paper I, Q6(c)
Approach: Explain external economies (Marshallian, industry-level) and their trade implications (clusters, path dependence, possible losses), then product variety (Krugman's monopolistic competition, love of variety, gains from variety), with examples.
Both ideas explain trade that comparative advantage based on endowments cannot, and lie at the heart of new trade theory.
External economies of scale (Marshall) arise when average costs fall as the size of the industry in a location grows, not the size of the firm: specialised suppliers, a pooled skilled labour market and knowledge spillovers. Implications: (i) trade patterns are shaped by clusters, such as watches in Switzerland, Silicon Valley, Bengaluru's software, Tiruppur's knitwear; (ii) history and accident matter: whichever country establishes an industry first gains a cost advantage that late entrants cannot easily overcome (path dependence); (iii) trade may even reduce welfare if an established high-cost producer prevents a potentially lower-cost country from entering, which gives an infant-industry argument.
Product variety: Krugman (1979, 1980), building on Dixit-Stiglitz (1977) monopolistic competition, assumes consumers value variety and firms face internal economies of scale. Each country can produce only a limited number of varieties profitably; trade enlarges the market, so each firm produces more at lower average cost while consumers enjoy more varieties. This generates intra-industry trade between similar countries, such as cars between Germany and France.
Significance: gains from trade arise even without comparative advantage; Broda and Weinstein (2006) estimated that new import varieties raised US welfare noticeably.
Hence external economies and variety explain trade among similar countries, and the role of clusters.

Question 7 (50 marks)

Q7(a) · Theories of Growth · 20 marks≈ 14 min
Neo-classical (Solow) and Endogenous Growth: Human Capital and R&D
Human capital and components of research and development are determining factors of economic growth. Explain using appropriate endogenous growth model.
हिंदी में प्रश्न
मानव-पूंजी तथा शोध एवं विकास के अवयव आर्थिक संवृद्धि के निर्धारक कारक हैं। यथोचित अंतर्जात संवृद्धि मॉडल का प्रयोग करते हुए व्याख्या कीजिए।
Practise this question Theories of Growth notes
Model answer
Paper and question: Paper I, Q7(a)
Approach: Use an endogenous growth framework: first the Mankiw-Romer-Weil and Lucas treatment of human capital, then Romer's R&D model, showing in each how the growth rate is determined; end with implications.
Endogenous growth models explain long-run growth by investment decisions inside the model, chiefly in human capital and in research and development, which escape the diminishing returns that limit growth in the Solow model.
Human capital: Mankiw, Romer and Weil (1992) used Y = K^α·H^β·(AL)^(1−α−β). With α + β less than 1 this is an augmented Solow model, and with α = β = 1/3 it explains about 80% of cross-country income differences. If α + β = 1, broad capital (physical plus human) has constant returns, giving an AK model, Y = AK, in which growth equals sA − δ and depends on the saving and schooling rates. Lucas (1988) made human capital accumulate as ḣ = δ(1 − u)h, so the growth rate of income per head equals δ(1 − u): more time devoted to education raises the long-run growth rate.
R&D (Romer, 1990): the economy has a final-goods sector, an intermediate-goods sector of monopolistically competitive firms holding patents, and a research sector. Knowledge grows as Ȧ = δ·H_A·A, so the growth rate is g = δH_A, rising with the human capital in research and its productivity. Ideas are non-rival and partly excludable: patents give firms the rents that motivate research, while spillovers to the stock of knowledge keep returns from diminishing.
Diagram: in the AK model, plot sA and the horizontal line δ (plus n) against k; sA lies above the line at every k, so the gap, the growth rate, is constant and there is no steady state in k, unlike Solow's intersection.
Implications: growth can differ permanently between countries; policies that raise schooling, research, patent protection and openness raise the growth rate, not just the level of income; and because of spillovers, markets under-invest, justifying public support. Critics note scale effects (Jones, 1995) and weak evidence for education quantity without quality.
Thus human capital and R&D are the determining factors of growth in endogenous growth theory.
Q7(b) · Theories of Growth · 15 marks≈ 11 min
Neo-classical (Solow) and Endogenous Growth: Human Capital and R&D
Explain the concept of steady-state in the context of Solow model.
हिंदी में प्रश्न
सोलो मॉडल के संदर्भ में, स्थिर-अवस्था अवधारणा की व्याख्या कीजिए।
Practise this question Theories of Growth notes
Model answer
Paper and question: Paper I, Q7(b)
Approach: Set out the Solow model's assumptions and fundamental equation, define the steady state and its properties (constant k, growth of Y at n, or n + g), show stability with the diagram, and the comparative statics.
In Robert Solow's model (1956), output is Y = F(K, L) with constant returns to scale and diminishing returns to each factor; in per-worker terms y = f(k), where k = K/L. A constant fraction s of output is saved and invested, labour grows at rate n and capital depreciates at rate δ.
The fundamental equation is k̇ = sf(k) − (n + δ)k: capital per worker rises when actual investment per worker, sf(k), exceeds break-even investment, (n + δ)k, needed to equip new workers and replace worn-out capital.
The steady state is the value k* at which k̇ = 0, i.e. sf(k*) = (n + δ)k*. In it, capital and output per worker are constant, while total capital and output grow at the rate of population growth n; with labour-augmenting technical progress at rate g, output per worker grows at g.
Diagram: k on the horizontal axis; the concave curve sf(k) and the straight line (n + δ)k from the origin; they cross at k*; to the left investment exceeds break-even and k rises, to the right it falls short and k falls; output per worker y* is read from f(k) above k*.
The steady state is unique and stable because of diminishing returns and the Inada conditions. A higher saving rate raises k* and y* but not the long-run growth rate; higher population growth lowers them. Hence economies with similar parameters converge to the same steady state (conditional convergence).
Q7(c) · Theories of Growth · 15 marks≈ 11 min
Neo-classical (Solow) and Endogenous Growth: Human Capital and R&D
What is the golden rule of capital accumulation? Explain it using a growth model.
हिंदी में प्रश्न
पूंजी संचयन का स्वर्णिम-सिद्धान्त क्या है? एक संवृद्धि मॉडल का प्रयोग करते हुए इसे समझाइए।
Practise this question Theories of Growth notes
Model answer
Paper and question: Paper I, Q7(c)
Approach: Define the golden rule (Phelps, 1961), derive the condition f′(k) = n + δ in the Solow model, show it on the diagram, give the Cobb-Douglas result s = α and the meaning of dynamic inefficiency.
The golden rule of capital accumulation, named by Edmund Phelps (1961), is the steady state with the highest consumption per worker. Since different saving rates give different steady states, the question is which one society should choose.
Consumption: in the Solow model, steady-state consumption per worker is c* = f(k*) − sf(k*) = f(k*) − (n + δ)k*, because sf(k*) = (n + δ)k* in the steady state.
Condition: maximise c* with respect to k*: dc*/dk* = f′(k*) − (n + δ) = 0, so the golden rule requires f′(k_gold) = n + δ: the marginal product of capital equals the population growth rate plus depreciation (n + g + δ with technical progress), i.e. the net return on capital equals the growth rate of the economy.
Cobb-Douglas case: with f(k) = k^α, αk^(α−1) = n + δ, and since sk^α = (n + δ)k, this gives s_gold = α: the economy should save a share of output equal to capital's share of income.
Diagram: f(k) and the line (n + δ)k against k; consumption is the vertical gap between them; it is largest at k_gold, where the slope of f(k) equals the slope of the line; the saving curve sf(k) passing through that point gives s_gold.
If actual k exceeds k_gold the economy is dynamically inefficient: saving less would raise consumption now and forever. If k is below k_gold, reaching it requires sacrificing consumption now for more later, so the golden rule is not automatically optimal once time preference is considered.

Question 8 (50 marks)

Q8(a) · Economic Development · 20 marks≈ 14 min
Development and Environmental Sustainability
How important is rent from extraction of renewable and non-renewable resources to distinguish between Net Domestic Product (NDP) and Environmentally adjusted Domestic Product (EDP). Will the distinction be valid if we have an economy with only renewable resources and the economy reaches the point of maximum sustainable yield?
हिंदी में प्रश्न
नवीनीकरणीय व गैर-नवीनीकरणीय संसाधनों के विदोहन से उत्पन्न लगान, शुद्ध घरेलू उत्पाद (एन.डी.पी.) एवं पर्यावरण-समायोजित उत्पाद (इ.डी.पी.) में भेद करने के लिये कितना महत्वपूर्ण है? यदि अर्थ व्यवस्था में केवल नवीनीकरणीय संसाधन हो तथा अर्थव्यवस्था अधिकतम-धारणीय उत्पादन के बिन्दु पर पहुँच गई हो, तो भी क्या यह विभेद मान्य होगा?
Practise this question Economic Development notes
Model answer
Paper and question: Paper I, Q8(a)
Approach: Define NDP and EDP (SEEA), explain how depletion of non-renewables (Hotelling rent) and of renewables (rent on harvest in excess of regeneration) creates the difference, then show that at maximum sustainable yield renewable depletion is zero, so the distinction largely disappears except for degradation.
Net Domestic Product (NDP) deducts the depreciation of produced capital from GDP but treats natural capital as free. The UN's System of Environmental-Economic Accounting (SEEA, 1993; Central Framework 2012) defines an Environmentally adjusted Domestic Product: EDP = NDP − depletion of natural resources − cost of environmental degradation.
Role of resource rent: depletion is valued by the rent the resource earns, i.e. (price − marginal extraction cost) × quantity depleted, because that rent is the value of the asset being used up. For a non-renewable resource (coal, oil), every unit extracted reduces the stock, so the whole Hotelling rent on extraction is a capital loss, not income; John Hartwick (1977) showed that this rent must be reinvested to keep consumption sustainable. In mineral-rich economies this deduction can be several per cent of GDP, so rent is crucial to the gap between NDP and EDP.
For a renewable resource (fish, forests, groundwater), the stock regenerates, so only harvest in excess of natural growth reduces the stock: depletion = rent × (harvest − regeneration). If harvest is less than growth, the stock rises and no deduction is made.
Economy with only renewables at maximum sustainable yield: with logistic growth G(S) = rS(1 − S/K), MSY occurs at S = K/2, where harvest equals regeneration (rK/4). The stock is constant, so depletion is zero and EDP equals NDP on the depletion account. The distinction therefore loses validity for depletion.
Diagram: regeneration G(S) as an inverted U against the stock S, peaking at K/2; a harvest line touching the peak shows MSY, where harvest equals growth and the stock is unchanged.
However, EDP may still differ from NDP if there is degradation (pollution, loss of soil quality or biodiversity) or if harvesting is not at MSY. Moreover, MSY is not the economically efficient stock when harvesting costs and discounting are considered (Gordon and Scott). So the distinction remains valid wherever degradation or non-sustainable harvesting occurs.
Q8(b) · Theories of Growth · 15 marks≈ 11 min
Balanced and Unbalanced Growth: Rosenstein-Rodan, Nurkse and Hirschman
"Balanced and unbalanced growth strategies are not substitutes but complementary to each other." Discuss.
हिंदी में प्रश्न
"संतुलित व असंतुलित संवृद्धि-रणनीतियों एक दूसरे की प्रतिस्थापक नहीं अपितु पूरक हैं।" चर्चा कीजिए।
Practise this question Theories of Growth notes
Model answer
Paper and question: Paper I, Q8(b)
Approach: Outline the balanced (Rosenstein-Rodan, Nurkse) and unbalanced (Hirschman) strategies, then argue complementarity: sequence, time horizon, and the role of planning and markets, with Indian illustration.
Balanced growth (Rosenstein-Rodan, 1943; Nurkse, 1953) calls for simultaneous investment in many complementary industries, so that each creates a market for the others and the vicious circle of poverty and the small market is broken by a 'big push'. Unbalanced growth (Hirschman, The Strategy of Economic Development, 1958) calls for deliberate investment in key sectors with strong linkages, so that the resulting shortages and pressures induce further investment.
They appear opposed, but they are complementary. First, unbalanced growth is a path to balance: Hirschman's imbalances are meant to be corrected by induced investment, so balance is the destination and imbalance the route.
Second, they apply to different levels and periods: balance is needed between broad sectors (agriculture and industry, SOC and DPA, consumer and capital goods) over the plan period, while imbalance can guide the sequence of projects within it. Third, balanced growth needs resources poor countries lack, while unbalanced growth economises on scarce decision-making ability; a mix suits the constraints.
India's planning illustrates this: the Second Plan's Mahalanobis strategy deliberately favoured heavy industry (imbalance), but the resulting food and foreign-exchange bottlenecks forced a shift to agriculture and the Green Revolution in the 1960s, restoring balance.
Hence a practical strategy uses unbalanced investment in leading sectors within a framework of overall balance; the two are stages of one process, not rival choices.
Q8(c) · Economic Development · 15 marks≈ 11 min
Myrdal, Kuznets and Structural Change; Role of Agriculture
"Income inequality is not a cause of concern as long as per capita income is rising." Critically examine this statement.
हिंदी में प्रश्न
"आय-असमानता चिन्ता का कारण नहीं है जब तक कि प्रति व्यक्ति आय में वृद्धि हो रही है।" इस कथन का आलोचनात्मक परीक्षण कीजिए।
Practise this question Economic Development notes
Model answer
Paper and question: Paper I, Q8(c)
Approach: Critically examine: present the 'trickle-down' view, then the arguments that inequality matters (welfare, poverty elasticity, growth, capabilities, political economy), with Indian evidence, and conclude.
The statement reflects the trickle-down view: if per capita income rises, the benefits eventually reach all, and inequality is a temporary by-product, as Kuznets's inverted U suggested. Rising average income can indeed reduce absolute poverty.
But the statement is too strong. (i) Welfare: with diminishing marginal utility of income, a given total gives less social welfare when distributed unequally; Atkinson's index and Sen's welfare measure, W = μ(1 − G), show that rising mean income can coexist with stagnant welfare if the Gini rises. (ii) Poverty: the higher the inequality, the less growth reduces poverty (the growth elasticity of poverty falls), as Ravallion showed.
(iii) Growth itself: high inequality can lower growth by limiting human capital investment by the poor under credit constraints (Galor and Zeira, 1993), shrinking the home market and generating demands for distortionary redistribution (Alesina and Rodrik, 1994); IMF studies (Ostry, Berg and co-authors, 2014) link lower inequality to longer growth spells. (iv) Capabilities: Sen's approach judges development by what people can do and be, not by average income.
In India, consumption inequality measured by HCES 2022–23 is moderate, but income and wealth inequality is high (World Inequality Lab estimates); the persistence of malnutrition despite fast growth shows that averages hide deprivation.
Hence rising per capita income is necessary but not sufficient; inequality matters both for its own sake and for sustained, inclusive growth.

UPSC Mains 2023 Economics Paper II