Frequently Asked Questions - Consumer's Equilibrium and Demand (Theory of Consumer Behaviour)

Frequently Asked Questions - Cbse Board Examinations

1. Define Microeconomics.

   Ans: Microeconomics is the branch of economics that studies the behaviour and decision-making of individual economic units such as consumers, firms and industries. It examines how prices and quantities of specific goods and services are determined, how resources are allocated between alternative uses, and how individual markets reach equilibrium under given constraints.

2. Why an economic problem does arises?

   Ans: An economic problem arises because human wants are unlimited while resources (land, labour, capital and entrepreneurship) are limited or scarce. Scarcity forces individuals and societies to make choices about what to produce, how to produce and for whom to produce, because it is not possible to satisfy all wants simultaneously with the available resources.

3. What are the central problems of an economy?

   Ans: The three central problems every economy must solve are:

   • What to produce - which goods and services and in what quantities;
   • How to produce - by which methods and combination of resources (labour-intensive or capital-intensive);
   • For whom to produce - how output is distributed among different individuals and groups in society.
   These decisions arise from scarcity and the need to allocate resources efficiently.
4. Define opportunity cost.

   Ans: Opportunity cost is the value of the next best alternative forgone when a choice is made. In other words, when resources are used for one purpose, the opportunity cost is the benefit that could have been received from using those resources in the next best alternative.

5. Define marginal opportunity cost.

   Ans: Marginal opportunity cost is the additional opportunity cost of producing one more unit of a good. It measures how much of another good must be given up to produce an extra unit of the first good. It is the change in total opportunity cost divided by the change in output.

6. Distinguish between 'micro' and 'macro' economics.

   Ans: Major distinctions between microeconomics and macroeconomics:

   • Scope: Microeconomics studies individual units (consumers, firms); macroeconomics studies the economy as a whole (national income, inflation, unemployment).
   • Focus: Micro focuses on price and output in individual markets; macro focuses on aggregates such as GDP, aggregate demand and supply.
   • Problems: Micro deals with resource allocation and market equilibrium; macro deals with economic growth, inflation control and overall stability.
   • Method: Micro often uses partial equilibrium analysis (one market at a time); macro uses general equilibrium and aggregate relationships.
   
   
7. Why PPC is Concave From the origin.

   Ans: The Production Possibility Curve (PPC) is concave to the origin because of the law of increasing opportunity cost. As production of one good increases, resources less suited to that good must be used, so larger and larger amounts of the other good must be sacrificed. Therefore, the opportunity cost rises and the PPC bends outward (concave), reflecting increasing marginal opportunity costs.

8. Define Marginal Rate of Transformation (MRT)

   Ans: The Marginal Rate of Transformation (MRT) is the rate at which one good must be sacrificed to produce an additional unit of another good. On the PPC it equals the absolute value of the slope of the curve at a point. MRT = change in quantity of good Y / change in quantity of good X (showing how much Y must be given up to gain one more unit of X).

9. Explain the problem, of 'what to produce' and 'how to produce.'

   Ans:

   • What to produce: Society must decide which combination of goods and services to produce (e.g., consumer goods vs capital goods, defence vs education). The choice depends on available resources, technology, preferences and social priorities.
   • How to produce: Once a decision on what to produce is made, society must choose the production technique - whether to use labour-intensive methods (more labour, less capital) or capital-intensive methods (more machines, less labour). The choice depends on factor prices, resource availability, technology and efficiency considerations.
   
   
10. Explain the central problem of how to produce with the help of an example.

    Ans: Suppose a country must produce either clothing or machinery. After choosing to produce a certain mix, it must decide how to produce each good. For clothing, it can use labour-intensive cottage industries or capital-intensive factory methods. If labour is cheap and abundant, labour-intensive production may be chosen to reduce costs and provide employment. If machinery and technology are abundant and labour is costly, capital-intensive methods may be chosen to increase productivity. Thus, the central problem of how to produce involves selecting the technique that best fits factor endowments, cost and policy objectives.

11. What is an indifference curve?

    Ans: An indifference curve is a locus of points representing different combinations of two goods that give the consumer the same level of satisfaction or utility. The consumer is indifferent among all combinations on the same curve because each point yields equal utility.

12. Define Utility.

    Ans: Utility is the satisfaction or pleasure a consumer derives from consuming goods and services. It is a measure of consumer wellbeing from consumption. Economists sometimes measure it in hypothetical units called "utils"; distinctions are also made between total utility (sum of satisfaction) and marginal utility (additional satisfaction from one more unit).

13. What is budget set?

    Ans: The budget set (or consumption set) is the collection of all combinations of two goods that a consumer can afford given his income and the prices of the goods. It includes all points on and below the budget line where total expenditure does not exceed income.

14. Define budget line.

    Ans: The budget line is the boundary of the budget set and shows all combinations of two goods that exhaust the consumer's income. Its equation is typically written as Px·X + Py·Y = M, where Px and Py are prices of goods X and Y and M is income. The slope of the budget line is -Px/Py, showing the rate at which one good can be substituted for the other given prices.

15. Define MRS.

    Ans: The Marginal Rate of Substitution (MRS) is the rate at which a consumer is willing to give up units of one good to obtain an additional unit of another good while keeping utility constant. Numerically, MRS at a point equals the slope of the indifference curve and is often expressed as MRS = MUx / MUy, where MU denotes marginal utilities.

16. A consumer consumes only two goods. Explain the conditions of consumer's equilibrium with the help of IC analysis.

    Ans: For a consumer choosing between two goods X and Y, equilibrium under indifference curve (IC) analysis occurs when:

    • The budget line is tangent to an indifference curve - that is, the consumer reaches the highest possible indifference curve within his budget.
    • The tangency condition implies MRS = Px / Py (rate of substitution equals the price ratio).
    • The consumer exhausts income (buys on the budget line).
    Explanation: At tangency, the slope of the IC (MRS) equals the slope of the budget line (-Px/Py). If MRS > Px/Py, the consumer values X relatively more and will buy more X; if MRS < px/py, the consumer will buy more y. thus equilibrium requires equality of mrs and price ratio and full use of />
17. For a consumer to be in equilibrium, why must MRS be equal to the ratio of price of two goods?

    Ans: MRS measures how much of Y the consumer is willing to give up for an extra unit of X while keeping utility constant. Px/Py measures how much of Y must be given up in the market to obtain an extra unit of X (the relative price). Equilibrium requires that subjective trade-off (MRS) equals objective market trade-off (Px/Py). If they differ, the consumer can increase utility by reallocating spending, so equality ensures no further beneficial reallocation is possible.

18. What is an indifference map?

    Ans: An indifference map is a set of several indifference curves shown together on the same graph. Each curve represents a different level of utility. Curves farther from the origin represent higher levels of satisfaction, and the map shows the consumer's preference ordering over many combinations of the two goods.

19. Explain the law of demand with the help of diagram and schedule.

    Ans: The law of demand states that, ceteris paribus, when the price of a good falls, the quantity demanded increases, and when the price rises, the quantity demanded decreases - showing an inverse relationship between price and quantity demanded.
    Example schedule:

    • Price (₹) - Quantity Demanded
    • 100 - 10
    • 80 - 15
    • 60 - 22
    • 40 - 32
    Graphically, plotting price on the vertical axis and quantity on the horizontal axis yields a downward-sloping demand curve. Each point on the curve corresponds to a price-quantity pair from the schedule, illustrating the inverse relationship.
20. Write three causes of increase / decrease in demand

    Ans: Three causes that can increase or decrease demand (shifts of the demand curve) are:

    • Income changes: An increase in consumer income raises demand for normal goods and lowers demand for inferior goods.
    • Prices of related goods: A rise in the price of a substitute good increases demand for the good; a rise in the price of a complement decreases demand.
    • Tastes and preferences / Expectations: Favourable changes in tastes or expectations of higher future prices can increase current demand; unfavourable changes can reduce demand.
    
    
21. Distinguish between the change in quantity demanded and change in demand.

    Ans:

    • Change in quantity demanded: Movement along the same demand curve caused only by a change in the price of the good. It is shown as movement from one point to another on the demand curve.
    • Change in demand: A shift of the entire demand curve either to the right (increase in demand) or to the left (decrease in demand) caused by non-price factors such as income, tastes, prices of related goods, expectations and population.
    
    
22. Explain any three factors or determinants of demand.

    Ans: Three important determinants of demand are:

    • Income of consumers: Higher income generally increases demand for normal goods and decreases demand for inferior goods.
    • Prices of related goods: Substitutes (e.g., tea and coffee): if the price of a substitute rises, demand for the good increases. Complements (e.g., cars and petrol): if the price of a complement rises, demand for the good decreases.
    • Tastes and preferences: Changes in fashions, advertising or social trends can increase or decrease demand irrespective of price.
    
    
23. Explain any three factors affecting elasticity of demand

    Ans: Three factors affecting price elasticity of demand are:

    • Availability of substitutes: The more and closer the substitutes for a good, the more elastic is its demand because consumers can switch easily.
    • Proportion of income spent on the good: Goods that take a larger share of a consumer's budget tend to have more elastic demand, as price changes noticeably affect spending.
    • Necessity versus luxury: Necessities usually have inelastic demand; luxuries have more elastic demand because consumers can reduce consumption more readily when price rises.
    
    
24. Explain the price elasticity of demand through geometric method.

    Ans: The geometric (graphical) method uses the demand curve and the point elasticity formula to show elasticity at a point. For a demand curve, price elasticity of demand (Ed) at a point is given by Ed = (ΔQ/ΔP) × (P/Q), where ΔQ/ΔP is the slope of the demand curve at that point. Geometrically:

    • If the demand curve is steep, |ΔQ/ΔP| is small and demand tends to be inelastic at that segment.
    • If the curve is flat, |ΔQ/ΔP| is large and demand tends to be elastic.
    • For a straight-line demand curve, elasticity varies along the curve: elastic at the upper left, unitary at midpoint, and inelastic at the lower right.
    This geometric view links the slope and the P/Q ratio to determine elasticity at any point on the curve.
25. Explain the price elasticity of demand through expenditure method

    Ans: The expenditure (total revenue) method compares how total expenditure (P × Q) changes when price changes:

    • If a price rise leads to a fall in total expenditure, demand is elastic (consumers reduce quantity enough that revenue falls).
    • If a price rise increases total expenditure, demand is inelastic (quantity falls little and revenue rises).
    • If total expenditure remains unchanged after a price change, demand is unitary elastic.
    Thus, observing the movement of total expenditure when price changes helps determine elasticity without calculating percentages.
26. Explain the properties of indifference curve.

    Ans: Standard properties of indifference curves are:

    • Downward sloping: To keep utility constant, an increase in one good must be accompanied by a decrease in the other.
    • Convex to the origin: Indifference curves bend inward because of diminishing marginal rate of substitution.
    • Higher curves preferred: Indifference curves farther from the origin represent higher levels of satisfaction.
    • Do not intersect: Two indifference curves cannot cross each other.
    • Infinite in number: An indifference map contains many such curves covering different utility levels.
    
    
27. Why can not two indifference curves meet each other?

    Ans: If two indifference curves intersected, it would imply that a single bundle gives two different levels of utility, which is contradictory. More precisely, intersection would violate the transitivity and consistency of preferences: a point on both curves would be indifferent to two different utility levels, producing logical inconsistency. Therefore, indifference curves cannot meet.

28. Why is indifference curve convex to origin?

    Ans: An indifference curve is convex to the origin because of the principle of diminishing marginal rate of substitution (MRS). As a consumer substitutes more of good X for good Y, the additional units of X bring less extra satisfaction, so the consumer is willing to give up fewer units of Y for further units of X. This diminishing willingness to substitute causes the curve to bend inward (convex).

29. Why does higher indifference curve gives higher levels of satisfaction?

    Ans: A higher indifference curve lies farther from the origin and represents combinations that include more of at least one good without reducing the quantity of the other. Since more of a good (or at least no less of any good) means greater or equal satisfaction, any point on a higher indifference curve gives a higher level of utility than any point on a lower curve.