Economics – I CBCBA3T04

Syllabus topics (RTMNU)

• Meaning, Scope and Objectives of Business Economics
• Law of Demand & Theory of Demand
• Indifference Curve Concept, Definition, Properties and Its Importance
• The elasticity of Demand concept, types, measurement and factors influencing the elasticity of Demand

Meaning, Scope and Objectives of Business Economics

Definition: Business Economics (also called Managerial Economics) is the use of economic theory and tools to solve business problems and to take better business decisions. Spencer and Siegelman call it "the integration of economic theory with business practice for decision-making and forward planning by management".

In simple words, it is the bridge between economics (theory) and business (practice). A firm uses it to decide what to produce, how much to produce, at what price, and at what cost.

Nature: It is mainly micro economic (it studies one firm), it is practical and applied, it is normative (it tells what a firm should do), and it also uses macro ideas like inflation, interest rates and government policy.

Scope (subject matter):

1. Demand analysis and forecasting – estimating how much consumers will buy, e.g. how many two-wheelers Hero MotoCorp can sell next year.
2. Production and cost analysis – choosing the best mix of inputs and keeping cost low.
3. Pricing decisions – fixing price under different markets.
4. Profit management – planning and measuring profit, break-even.
5. Capital management – choosing investment projects.
6. Market structure analysis – knowing the competition the firm faces.
7. Macro environment – effect of inflation, RBI policy, taxes (GST) and the Union Budget on the firm.

Objectives:

1. To help management take rational decisions.
2. To forecast demand, cost and profit for forward planning.
3. To make the best use of scarce resources.
4. To fix suitable prices and earn reasonable profit.
5. To understand and adjust to the economic environment.

Law of Demand & Theory of Demand

Demand: Demand means the desire for a good backed by the ability and willingness to pay for it, at a given price and time. A wish without money is not demand.

Determinants of demand: price of the good, income of the consumer, prices of related goods (substitutes like tea and coffee; complements like car and petrol), tastes and fashion, population, expectations of future prices, and government policy (taxes, subsidies).

Law of Demand (definition): Other things remaining the same, when the price of a good falls, its quantity demanded rises, and when price rises, quantity demanded falls. There is an inverse relation between price and quantity demanded.

Demand curve: When this schedule is drawn with price on the Y-axis and quantity on the X-axis, we get a curve that slopes downward from left to right.

Assumptions: income, tastes, prices of related goods, population and expectations do not change.

Why does demand rise when price falls? (1) Law of diminishing marginal utility, (2) income effect – real income rises, (3) substitution effect – the good becomes cheaper than substitutes, (4) new buyers enter the market, (5) many uses of the good.

Exceptions: Giffen goods (very inferior goods of poor people), prestige or Veblen goods (diamonds, luxury cars), fear of future price rise (people buy more onions when prices start rising), ignorance of quality, and necessities like salt and medicines.

Indifference Curve – Concept, Definition, Properties and Importance

Definition: An indifference curve (IC) is a curve showing different combinations of two goods that give the consumer the same level of satisfaction, so the consumer is indifferent between them. The approach was developed by J.R. Hicks and R.G.D. Allen (1934). It uses ordinal utility (ranking), not cardinal (counting) utility.

Marginal Rate of Substitution (MRS) is the amount of one good the consumer gives up to get one more unit of the other good, keeping satisfaction the same. A set of ICs is called an indifference map.

Properties:

1. Slopes downward from left to right – to get more of one good, the consumer must give up some of the other.
2. Convex to the origin – because MRS diminishes (4, 3, 2 in the table).
3. Two ICs never cut each other – one point cannot give two levels of satisfaction.
4. Higher IC = higher satisfaction – it shows more of both goods.
5. An IC does not touch either axis (normally) – the consumer wants some of both goods.

Importance: explains consumer's equilibrium (where the budget line touches the highest IC), separates income and substitution effects, explains Giffen goods, useful in exchange, rationing, taxation and welfare analysis, and needs no measurement of utility in numbers.

Elasticity of Demand – Concept, Types, Measurement and Factors

Definition: Elasticity of demand is the degree of responsiveness of quantity demanded to a change in its price (or income, or price of a related good). Price elasticity (Marshall): Ed = Percentage change in quantity demanded ÷ Percentage change in price.

Types: (a) Price elasticity, (b) Income elasticity, (c) Cross elasticity. Degrees of price elasticity:

Measurement:

1. Percentage (proportionate) method: Ed = (ΔQ/Q) ÷ (ΔP/P). Example: price of a pen falls from ₹10 to ₹8 and demand rises from 100 to 150. ΔQ/Q = 50/100 = 0.5; ΔP/P = 2/10 = 0.2; Ed = 0.5/0.2 = 2.5 (elastic; the minus sign is ignored).
2. Total outlay method (Marshall): if total spending rises when price falls, Ed > 1; if it stays the same, Ed = 1; if it falls, Ed < 1.
3. Point (geometric) method: Ed at a point on a straight-line demand curve = Lower segment ÷ Upper segment.
4. Arc method: uses average of old and new values; for the pen example, Ed = (50/125) ÷ (2/9) = 1.8.

Factors influencing elasticity: nature of the good (necessity or luxury), availability of substitutes, number of uses, share of income spent on it, habits, possibility of postponing use, time period (demand is more elastic in the long run), and range of price.

Likely exam questions

1. (Long, 8/16 marks) Define Business Economics. Explain its scope and objectives.
2. (Long, 8/16 marks) What is an indifference curve? Explain its properties and importance. OR Define elasticity of demand. Explain its types, methods of measurement and the factors influencing it.
3. (Short, 4 marks) State the Law of Demand and its exceptions.
4. (Short, 4 marks) Explain the total outlay method of measuring elasticity of demand.
5. (Short, 4 marks) What is Marginal Rate of Substitution?

Syllabus topics (RTMNU)

• Concept of the production function
• Meaning
• Cobb-Douglas Production Function
• ISO quant- Concept, Properties
• Law of variable proportion, Assumptions, Significance and limitations
• Law of Return to Scale

Concept of the Production Function, Meaning, Cobb-Douglas Production Function

Production: In economics, production means the creation of utility (usefulness) by turning inputs into output, e.g. a sugar factory turns sugarcane into sugar.

Definition: A production function shows the technical (physical) relationship between the inputs used by a firm and the maximum output it can produce, with a given technology. It is written as:

Q = f (L, K, N, E, T)

where Q = output, L = labour, K = capital, N = land, E = entrepreneur (organisation), T = technology. For simple study we use Q = f (L, K).

Features:

1. It shows a physical relation, not a money relation.
2. It depends on the given state of technology; new technology gives a new production function.
3. It shows the maximum output from a given set of inputs.
4. Inputs can be substituted for each other up to a limit.
5. It has a short-run form (one input variable) and a long-run form (all inputs variable).

Short run and long run: In the short run some inputs (machines, building) are fixed, and only labour/raw material can be changed – this gives the Law of Variable Proportions. In the long run all inputs can be changed – this gives the Laws of Returns to Scale.

Cobb-Douglas Production Function: It was developed by C.W. Cobb and P.H. Douglas (1928) from data of American manufacturing. Its form is:

Q = A L^α K^β

where A = technology (efficiency) constant, α = output elasticity of labour, β = output elasticity of capital. In the original study α was about 0.75 and β about 0.25, so α + β = 1.

Features / uses:

1. Returns to scale are shown by α + β: if α + β = 1, constant returns; if > 1, increasing returns; if < 1, decreasing returns.
2. α and β show the share of labour and capital in total output.
3. Elasticity of substitution between labour and capital is equal to 1.
4. It is easy to estimate with real data, so it is widely used in research and planning.

Example: If Q = 10 L^0.5 K^0.5, with L = 4 and K = 9, Q = 10 × 2 × 3 = 60 units. If both L and K are doubled (8 and 18), Q becomes 120 – output doubles, so constant returns to scale (0.5 + 0.5 = 1).

Limitations: it considers only two inputs, assumes constant technology, assumes elasticity of substitution is always 1, and cannot show all three stages of returns together.

ISO quant – Concept, Properties

Definition: An isoquant ("iso" = equal, "quant" = quantity) is a curve showing all the combinations of two inputs (labour and capital) that produce the same level of output. It is also called the equal-product curve or production indifference curve.

MRTS (Marginal Rate of Technical Substitution) is the amount of capital the firm can give up for one more unit of labour while output stays the same. A group of isoquants is called an isoquant map.

Properties:

1. Slopes downward from left to right – more labour means less capital for the same output.
2. Convex to the origin – because MRTS diminishes (5, 4, 3).
3. Two isoquants never cut each other – one combination cannot give two outputs.
4. Higher isoquant shows higher output – e.g. IQ for 200 units lies above IQ for 100 units.
5. Does not touch either axis – both inputs are needed for production.

Producer's equilibrium: The firm gets least-cost production where the isocost line (combinations of inputs the firm can buy with a given budget) is tangent to the isoquant.

Law of Variable Proportion, Assumptions, Significance and Limitations

Statement: When more and more units of a variable input (labour) are added to a fixed input (land or machines), total output first increases at an increasing rate, then at a diminishing rate, and finally falls. It is a short-run law.

Three stages:

1. Stage I – Increasing returns: MP rises, TP rises fast. Reason: fixed input is under-used; better division of labour.
2. Stage II – Diminishing returns: MP falls but is positive; TP rises slowly and is maximum when MP = 0. Reason: fixed input becomes scarce compared to labour. A rational firm works in this stage.
3. Stage III – Negative returns: MP is negative and TP falls. Reason: too many workers crowd the fixed input.

Assumptions: technology is constant; only one input is variable and others are fixed; all units of the variable input are equal in efficiency; inputs can be changed in small units; short period.

Significance: it guides a firm on how many workers to employ; it explains why farm output per worker is low in over-populated agriculture (disguised unemployment in India); it is the base of the theory of cost (rising MP means falling cost); and it shows the importance of new technology to delay diminishing returns.

Limitations: technology does not stay constant in real life; units of labour are not equal; some inputs cannot be divided; it does not apply when all inputs are changed together (long run).

Law of Return to Scale

Meaning: Returns to scale show how output changes when all inputs are increased in the same proportion in the long run (change in the scale of production).

1. Increasing returns to scale: output increases by a greater proportion than inputs (inputs +100%, output +150%). Causes: internal economies – specialisation, large machines, bulk buying.
2. Constant returns to scale: output increases in the same proportion (inputs +100%, output +100%). Economies and diseconomies balance.
3. Diminishing returns to scale: output increases by a smaller proportion (inputs +100%, output +60%). Causes: diseconomies – management problems, delay in decisions, lack of coordination.

Likely exam questions

1. (Long, 8/16 marks) Explain the Law of Variable Proportions with a table and diagram. State its assumptions, significance and limitations.
2. (Long, 8/16 marks) What is a production function? Explain the Cobb-Douglas production function. OR Explain the Law of Returns to Scale.
3. (Short, 4 marks) Define isoquant and state its properties.
4. (Short, 4 marks) Distinguish between the Law of Variable Proportions and Returns to Scale.
5. (Short, 4 marks) What is Marginal Rate of Technical Substitution?

Syllabus topics (RTMNU)

• Concept of Cost in Short Run
• Accounting Cost
• Economic Cost
• Opportunity Cost
• Fixed Cost
• Variable Cost
• Direct Cost
• Indirect Cost
• Real Cost
• Money Cost
• Total Cost
• Marginal Cost
• Average cost
• Total, Marginal and Average cost in Long Run
• Revenue- Total Revenue, Average Revenue, Marginal Revenue and their relationship
• Market Structure

Concept of Cost in Short Run – Different Cost Concepts

Cost: Cost of production is the total expenditure a firm makes on inputs (raw material, wages, rent, interest, power) to produce a given output.

Short run is a period in which some inputs (plant, building) are fixed. Long run is a period long enough to change all inputs.

1. Accounting cost (explicit cost): actual money paid to outsiders and recorded in the books – wages, rent, raw material, electricity.
2. Economic cost: accounting (explicit) cost plus implicit cost – the value of the owner's own inputs like own capital, own building and own labour. Economic profit = Revenue – Economic cost.
3. Opportunity cost: the value of the next best alternative given up. Example: if a farmer grows sugarcane on land that could earn ₹50,000 from cotton, the opportunity cost of sugarcane is ₹50,000.
4. Fixed cost (FC): cost that does not change with output and is paid even at zero output – rent, salary of permanent staff, insurance, depreciation.
5. Variable cost (VC): cost that changes directly with output – raw material, wages of daily workers, power. VC is zero at zero output.
6. Direct cost: cost that can be directly traced to a product, e.g. cloth used in a shirt.
7. Indirect cost: cost that cannot be traced to one product, e.g. factory rent shared by many products.
8. Real cost: the efforts, pains and sacrifices of workers, landlords and savers in producing a good (Marshall's idea).
9. Money cost: the cost of production expressed in money (₹).
10. Total cost (TC): TC = TFC + TVC.
11. Average cost (AC): cost per unit; AC = TC ÷ Q = AFC + AVC.
12. Marginal cost (MC): the addition to total cost from producing one more unit; MC = TC_n – TC_n–1.

Shapes of short-run curves: TFC is a horizontal line; AFC keeps falling (a rectangular hyperbola); AVC, AC and MC are U-shaped because of the Law of Variable Proportions. MC cuts AVC and AC at their lowest points.

Total, Marginal and Average Cost in Long Run

In the long run all costs are variable; there is no fixed cost. The firm can choose any plant size.

1. Long-run Total Cost (LTC) starts from the origin, since there is no fixed cost.
2. Long-run Average Cost (LAC): it is the envelope of many short-run AC curves (one for each plant size). It is called the planning curve because it helps a firm choose the best plant size. It is U-shaped but flatter than SAC – it falls due to economies of scale, then rises due to diseconomies of scale.
3. Long-run Marginal Cost (LMC): the change in LTC from one more unit of output. LMC cuts LAC at its lowest point (the optimum scale).

Revenue – Total Revenue, Average Revenue, Marginal Revenue and their Relationship

Revenue is the money a firm receives from selling its output.

• Total Revenue (TR) = Price × Quantity sold.
• Average Revenue (AR) = TR ÷ Q. AR is always equal to price, so the AR curve is the firm's demand curve.
• Marginal Revenue (MR) = TR_n – TR_n–1, the extra revenue from one more unit sold.

(a) Perfect competition (price constant at ₹10): TR = 10, 20, 30…; AR = MR = ₹10. AR and MR are the same horizontal line.

(b) Imperfect competition (price must fall to sell more):

Relationship:

1. When AR is constant, MR = AR.
2. When AR falls, MR falls faster and lies below AR.
3. When MR is positive, TR rises; when MR = 0, TR is maximum; when MR is negative, TR falls.
4. Relation with elasticity: MR = AR × (e – 1) / e. So when e = 1, MR = 0.

Market Structure

Market in economics means the whole area where buyers and sellers are in contact for buying and selling a good, not only a fixed place. Markets are classified by number of sellers, nature of product, freedom of entry and control over price.

Likely exam questions

1. (Long, 8/16 marks) Explain the various concepts of cost: accounting cost, economic cost, opportunity cost, fixed and variable cost, direct and indirect cost, real and money cost. Explain short-run TC, AC and MC with a table.
2. (Long, 8/16 marks) Explain the concepts of Total, Average and Marginal Revenue and their relationship under perfect and imperfect competition. OR Explain the different forms of market structure.
3. (Short, 4 marks) Distinguish between fixed cost and variable cost.
4. (Short, 4 marks) What is opportunity cost? Give an example.
5. (Short, 4 marks) Why is the long-run average cost curve called the planning curve?

Syllabus topics (RTMNU)

• Price-Output Determination Under Perfect Competition Market
• Price-Output Determination Under Monopoly Market
• Price-Output Determination Under Monopolistic Competition
• Price Discrimination

Price-Output Determination Under Perfect Competition Market

Definition: Perfect competition is a market with a very large number of buyers and sellers selling a homogeneous (identical) product at one uniform price, with free entry and exit and perfect knowledge.

Features: (1) large number of buyers and sellers, (2) homogeneous product, (3) free entry and exit of firms, (4) perfect knowledge of the market, (5) perfect mobility of factors, (6) no transport cost, (7) one uniform price. The firm is a price taker; the industry is the price maker.

Price determination by the industry: The market price is fixed where the industry's total demand equals total supply. Every firm accepts this price, so for the firm AR = MR = Price (a horizontal line).

Equilibrium of the firm – two conditions:

1. MC = MR.
2. MC curve must cut MR from below (MC must be rising).

Short-run equilibrium: the firm may earn (a) super-normal profit if AR > AC, (b) normal profit if AR = AC, or (c) a loss if AR < AC. A firm making a loss continues to produce in the short run as long as price covers average variable cost (AVC). If price falls below minimum AVC, it shuts down – this is the shut-down point.

Long-run equilibrium: If firms earn super-normal profit, new firms enter, supply increases and price falls. If they make losses, some firms leave and price rises. Finally every firm earns only normal profit. Long-run condition: Price = AR = MR = MC = minimum AC. The firm produces at the lowest point of the LAC – the optimum size.

Price-Output Determination Under Monopoly Market

Definition: Monopoly is a market where there is a single seller of a product that has no close substitute, and entry of new firms is blocked. "Mono" means one and "poly" means seller.

Features: (1) one seller, (2) no close substitute, (3) barriers to entry (patent, licence, control of raw material, huge capital), (4) firm and industry are the same, (5) the monopolist is a price maker, (6) price discrimination is possible.

Indian examples: Indian Railways in passenger rail transport; earlier, state electricity boards in power distribution in their area.

Equilibrium: The monopolist faces a downward-sloping AR (demand) curve, and MR lies below AR. It is in equilibrium where MC = MR and MC cuts MR from below. The price is then read from the AR curve above that output.

• Short run: it may earn super-normal profit (AR > AC), normal profit, or even a loss if demand is weak.
• Long run: because entry is blocked, the monopolist can keep earning super-normal profit.

Points to note: monopoly price is higher and output lower than under perfect competition; the monopolist always produces where demand is elastic (MR positive); it may not produce at minimum AC, so resources are not fully used.

Price-Output Determination Under Monopolistic Competition

Definition: Monopolistic competition is a market with many sellers selling differentiated products that are close substitutes. The idea was given by E.H. Chamberlin (1933). Examples: soaps (Lux, Lifebuoy, Santoor), toothpaste (Colgate, Pepsodent, Dabur Red), restaurants and hair salons.

Features:

1. Many sellers – each has a small share of the market.
2. Product differentiation – by brand, packing, colour, quality or service.
3. Selling costs – heavy spending on advertising and sales promotion.
4. Free entry and exit.
5. Some control over price – because of brand loyalty; the AR curve slopes down but is quite elastic.
6. Group instead of industry – firms producing close substitutes.

Short-run equilibrium: each firm is in equilibrium where MC = MR. Depending on AR and AC, it may earn super-normal profit, normal profit or a loss.

Long-run equilibrium: super-normal profit attracts new firms with similar brands; each firm's demand falls until the AR curve just touches the AC curve (tangency). So in the long run each firm earns only normal profit: MR = MC and AR = AC. The tangency is on the falling part of AC, so firms work below optimum capacity – this unused capacity is called excess capacity.

Price Discrimination

Definition: Price discrimination means charging different prices to different buyers for the same product, when the difference is not due to differences in cost. Example: a doctor charging lower fees to poor patients; railways charging different fares for sleeper and AC classes; cinema halls charging lower tickets for morning shows; electricity boards charging lower rates for farmers than for shops.

Degrees (A.C. Pigou):

1. First degree (perfect): each buyer is charged the maximum he is willing to pay; the whole consumer surplus goes to the seller.
2. Second degree: buyers are charged different prices for different blocks of quantity, e.g. lower rate per unit for higher use.
3. Third degree: the market is divided into sub-markets (by age, place, time) and a different price is charged in each – the most common type, e.g. student concession.

Conditions: (1) the seller must have monopoly power; (2) the markets must be separate so the good cannot be resold from the cheap market to the dear market; (3) elasticity of demand must be different in the sub-markets.

Equilibrium under third degree: total output is fixed where combined MR = MC, and it is divided so that MR in each market is equal (MR₁ = MR₂ = MC). A higher price is charged in the market with less elastic demand and a lower price where demand is more elastic.

Is it good? It can be useful – a service that could not run at one price may run with discrimination, and poor people can get cheaper service (e.g. concession fares). It is harmful when it exploits consumers only to raise profit.

Likely exam questions

1. (Long, 8/16 marks) Explain price and output determination of a firm under perfect competition in the short run and the long run.
2. (Long, 8/16 marks) What is monopoly? Explain price-output determination under monopoly. OR What is price discrimination? Explain its degrees, conditions and equilibrium.
3. (Short, 4 marks) State the features of monopolistic competition.
4. (Short, 4 marks) What is excess capacity under monopolistic competition?
5. (Short, 4 marks) State the conditions necessary for price discrimination.