Consumer's Equilibrium
Class 11 Microeconomics Chapter 2 | NCERT Solutions (2026) + Important Questions
Welcome students! Agar aap Class 11 Commerce ya Humanities mein hain, toh aapko pata hoga ki Economics kitna scoring aur interesting subject hai. Aaj hum cover karne wale hain ek bahut hi important chapter: Chapter 2 - Consumer Equilibrium.
In this highly detailed guide, we are providing the complete NCERT Solutions for Class 11 Microeconomics Chapter 2, perfectly tailored for the Board Exam Questions 2026 and upcoming CUET exams. In this chapter, you will learn how a consumer decides exactly how much to buy to get maximum satisfaction from their limited pocket money.
From understanding the Law of Diminishing Marginal Utility to mastering the Indifference Curve, this chapter is the core of microeconomics. Humne sari explanations ko bahut hi simple Hinglish mein rakha hai, so that you can understand complex concepts without any tension. Let's dive in and boost your exam prep!
📝 Chapter Overview
Here is a quick snapshot of what you are dealing with in this chapter:
| Feature | Details |
|---|---|
| Chapter Name | Consumer's Equilibrium |
| Subject | Microeconomics |
| Class | Class 11 |
| Board | CBSE / State Boards following NCERT |
| Important Topics | Law of DMU, Indifference Curve, Budget Line, Consumer's Equilibrium |
| Difficulty Level | High (Requires logical understanding) |
| Exam Weightage | 10 to 12 Marks |
🎯 Learning Objectives
After completing this chapter, students will be able to:
- Understand the meaning of Utility, Total Utility (TU), and Marginal Utility (MU).
- Explain the Law of Diminishing Marginal Utility (DMU) with real-life examples.
- Determine Consumer's Equilibrium in the case of a single commodity and two commodities using the Utility approach.
- Understand the concept of the Indifference Curve (IC), Budget Line, and Budget Set.
- Find Consumer's Equilibrium using the Indifference Curve approach.
🔑 Key Concepts, Definitions & Formulas
Before we jump into the solutions, let's revise the core concepts fatafat:
- Utility: The want-satisfying power of a commodity. It is the satisfaction you get from consuming something.
- Total Utility (TU): The total satisfaction derived from consuming all given units of a commodity.
- Marginal Utility (MU): The additional utility derived from the consumption of one more unit of the given commodity.
Formula:MUn = TUn - TUn-1 - Law of Diminishing Marginal Utility (DMU): As a consumer consumes more and more units of a specific commodity, the utility derived from each successive unit goes on diminishing.
- Indifference Curve (IC): A curve showing different combinations of two goods, each yielding the same level of satisfaction to the consumer.
- Marginal Rate of Substitution (MRS): The rate at which a consumer is willing to substitute one good for another without changing the level of satisfaction.
Formula:MRSxy = ΔY / ΔX - Budget Line: A graphical representation of all possible combinations of two goods which can be purchased with given income and prices, such that the cost of each of these combinations is exactly equal to the money income of the consumer.
Equation:P1X1 + P2X2 = M(where P is price, X is quantity, M is income) - Monotonic Preferences: A consumer's preferences are called monotonic if, between any two bundles, the consumer always chooses the bundle having more of at least one good and no less of the other good.
📚 Full NCERT Solutions: Class 11 Microeconomics Chapter 2
Here are the complete, step-by-step NCERT exercise solutions for this chapter. Every question is answered in proper board-exam writing style.
Question 1: What do you mean by utility?
Answer:
Utility refers to the want-satisfying power of a commodity. It is the amount of satisfaction a consumer derives from the consumption of a specific good or service. Utility is a subjective concept; it varies from person to person, place to place, and time to time.
Question 2: How is total utility derived from marginal utility?
Answer:
Total Utility (TU) is the sum of all the Marginal Utilities (MU) derived from the consumption of successive units of a commodity.
Mathematically: TU = MU1 + MU2 + MU3 + ... + MUn or TU = ΣMU.
As long as MU is positive, TU increases. When MU becomes zero, TU is maximum. When MU becomes negative, TU starts falling.
Question 3: State the law of diminishing marginal utility.
Answer:
The Law of Diminishing Marginal Utility (DMU) states that as we consume more and more units of a commodity continuously, the additional satisfaction (Marginal Utility) derived from each successive unit goes on decreasing. For example, your first slice of pizza gives you immense satisfaction, but the fourth or fifth slice won't give you the same level of joy.
Question 4: What are the conditions of consumer's equilibrium under the utility analysis?
Answer:
Under utility analysis, consumer's equilibrium depends on the number of commodities:
1. In case of a Single Commodity:
The consumer is in equilibrium when the Marginal Utility of the good (in terms of money) is exactly equal to its price.
Condition: MUx / MUm = Px (Where MUm is Marginal Utility of Money).
2. In case of Two Commodities (Law of Equi-Marginal Utility):
A consumer reaches equilibrium when the ratio of Marginal Utility to price is equal for both goods, and MU falls as consumption increases.
Condition: MUx / Px = MUy / Py = MUm.
Question 5: What do you mean by the budget set of a consumer?
Answer:
A Budget Set is a quantitative collection of all the possible bundles or combinations of two goods that a consumer can afford to buy with his/her given income and the prevailing market prices of the goods.
Question 6: What is a budget line?
Answer:
A Budget Line (or Price Line) is a graphical representation of all those combinations of two goods which a consumer can buy by spending his entire given income, at the given market prices. The equation is: P1X1 + P2X2 = M.
Question 7: Explain why the budget line is downward sloping.
Answer:
The budget line is downward sloping because a consumer has a limited or fixed income. If they want to consume more units of Good 1, they must give up or sacrifice some units of Good 2. This inverse relationship between the quantities of the two goods causes the budget line to slope downwards from left to right.
Question 8: A consumer wants to consume two goods. The prices of the two goods are Rs 4 and Rs 5 respectively. The consumer's income is Rs 20.
(i) Write down the equation of the budget line.
(ii) How much of good 1 can the consumer consume if she spends her entire income on that good?
(iii) How much of good 2 can she consume if she spends her entire income on that good?
(iv) What is the slope of the budget line?
Answer:
Given: Price of Good 1 (P1) = Rs 4, Price of Good 2 (P2) = Rs 5, Income (M) = Rs 20.
(i) Equation: 4X1 + 5X2 = 20
(ii) Max Good 1: If entire income is spent on Good 1, quantity = M / P1 = 20 / 4 = 5 units.
(iii) Max Good 2: If entire income is spent on Good 2, quantity = M / P2 = 20 / 5 = 4 units.
(iv) Slope: The slope of the budget line is -P1 / P2 = -4 / 5 = -0.8.
Question 9: How does the budget line change if the consumer's income increases to Rs 40 but the prices remain unchanged?
Answer:
When income increases from Rs 20 to Rs 40 and prices remain constant, the consumer's purchasing power increases. As a result, the budget line will shift parallel to the right (outward shift). The new equation will be 4X1 + 5X2 = 40.
Question 10: How does the budget line change if the price of good 2 decreases by a rupee but the price of good 1 and the consumer's income remain unchanged?
Answer:
If P2 decreases from Rs 5 to Rs 4, Good 2 becomes relatively cheaper. The consumer can now buy more of Good 2 with the same income. The budget line will rotate outwards on the Y-axis (Good 2 axis), while its intercept on the X-axis (Good 1) will remain the same.
Question 11: What happens to the budget set if both the prices as well as the income double?
Answer:
If both prices and income double, the budget line will remain unchanged. The real purchasing power of the consumer stays exactly the same. (e.g., instead of 4X1 + 5X2 = 20, it becomes 8X1 + 10X2 = 40, which simplifies back to the original equation). The budget set remains the same.
Question 12: Suppose a consumer can afford to buy 6 units of good 1 and 8 units of good 2 if she spends her entire income. The prices of the two goods are Rs 6 and Rs 8 respectively. How much is the consumer's income?
Answer:
Income (M) is calculated using the budget line equation: M = P1X1 + P2X2
Given: P1 = Rs 6, X1 = 6, P2 = Rs 8, X2 = 8.
M = (6 × 6) + (8 × 8) = 36 + 64 = 100.
The consumer's income is Rs 100.
Question 13: Suppose a consumer wants to consume two goods which are available only in integer units. The two goods are equally priced at Rs 10 and the consumer's income is Rs 40. Write down all the bundles that are available to the consumer.
Answer:
Equation: 10X1 + 10X2 ≤ 40, meaning X1 + X2 ≤ 4.
Since goods are available in integer units, the possible bundles (X1, X2) are:
- (0,0), (0,1), (0,2), (0,3), (0,4)
- (1,0), (1,1), (1,2), (1,3)
- (2,0), (2,1), (2,2)
- (3,0), (3,1)
- (4,0)
Question 14: What do you mean by 'monotonic preferences'?
Answer:
Monotonic preferences mean that a rational consumer always prefers a bundle that gives him more of at least one good and no less of the other good compared to another bundle. Because more goods mean more satisfaction.
Question 15: If a consumer has monotonic preferences, can she be indifferent between the bundles (10, 8) and (8, 6)?
Answer:
No. If preferences are monotonic, the consumer will definitely prefer bundle (10, 8) over (8, 6) because bundle (10, 8) contains more units of both goods, thus providing a higher level of satisfaction. She cannot be indifferent.
Question 16: Suppose a consumer's preferences are monotonic. What can you say about her preference ranking over the bundles (10, 10), (10, 9) and (9, 9)?
Answer:
Because the consumer has monotonic preferences, she will always prefer the bundle with more goods. Therefore, her ranking will be:
- Rank 1: (10, 10) - Highest satisfaction
- Rank 2: (10, 9)
- Rank 3: (9, 9) - Lowest satisfaction
Question 17: Suppose your friend is indifferent to the bundles (5, 6) and (6, 6). Are the preferences of your friend monotonic?
Answer:
No. Bundle (6, 6) has one more unit of the first good and the same amount of the second good compared to bundle (5, 6). If preferences were monotonic, your friend should strictly prefer (6, 6). Since he is indifferent, his preferences are not monotonic.
⚡ Extra Important Questions Board Style 2026
To give you an extra edge for your board exams and CUET prep, here are 15 important practice questions.
Multiple Choice Questions (MCQs)
1. Utility is a ________ concept.
2. At the point of satiety (maximum satisfaction), Marginal Utility is:
3. An Indifference Curve is convex to the origin because of:
4. If the equation of a budget line is 2X + 3Y = 60, the maximum amount of Y that can be purchased is:
5. Consumer's equilibrium through Indifference Curve approach occurs when:
Short Answer Questions (3 Marks)
6. Distinguish between Total Utility and Marginal Utility.
Answer: Total Utility (TU) is the sum of utility derived from consuming all units of a commodity, whereas Marginal Utility (MU) is the additional utility derived from consuming one extra unit. TU increases as long as MU is positive. When MU is zero, TU is maximum. Difficulty: Easy
7. Why can two Indifference Curves never intersect each other?
Answer: If two ICs intersect, it would mean that at the point of intersection, the same bundle of goods yields two different levels of satisfaction, which is logically impossible. Each IC represents a distinct and specific level of satisfaction. Difficulty: Medium
8. State three properties of an Indifference Curve.
Answer:
1. They slope downwards from left to right.
2. They are strictly convex to the origin due to diminishing MRS.
3. Higher IC represents a higher level of satisfaction. Difficulty: Easy
Long Answer Questions (6 Marks)
9. Explain the Consumer's Equilibrium in the case of a single commodity using marginal utility analysis.
Answer: A consumer is in equilibrium when they maximize their satisfaction from spending their given income. In the case of a single commodity (say, Good X), equilibrium is struck when the marginal utility of the good in terms of money is equal to its price. Condition: MUx / Px = MUm.
If MUx / Px > MUm, the consumer is getting more worth than the price paid, so they will buy more, causing MU to fall (due to Law of DMU) until equilibrium is restored. If MUx / Px < MUm they will reduce consumption until equality is achieved. Difficulty: Hard
10. Using an Indifference Curve and Budget Line, explain the conditions of consumer's equilibrium.
Answer: According to the ordinal utility approach, a consumer attains equilibrium when two conditions are fulfilled:
1. MRSxy = Px / Py: The budget line must be tangent to the Indifference Curve. Here, the rate at which the consumer is willing to substitute X for Y is equal to the market rate of exchange.
2. IC must be convex at the point of tangency: This means MRS must be diminishing. If the budget line intersects the IC, it means the consumer can reach a higher IC by reallocating their budget. The tangency point ensures maximum possible satisfaction within the budget. Difficulty: Hard
11. Explain the Law of Diminishing Marginal Utility with the help of a schedule and diagram.
Answer: (Provide a standard schedule where units increase, MU decreases, becomes 0, then negative. Draw the corresponding downward-sloping MU curve and the inverted-U TU curve).
The law states that as successive units of a good are consumed, the extra utility derived declines. Example: drinking glasses of water when thirsty. The first glass gives maximum utility, the second gives lesser, the third might give zero, and the fourth might make you feel sick (negative utility). Difficulty: Medium
Case-Based Questions
12. Read the following case:
Rahul has ₹100. He loves chocolates (₹20) and chips (₹10). He is currently buying 3 chocolates and 4 packets of chips. He realizes that the marginal utility of the last chocolate is 40 utils, and the marginal utility of the last chips packet is 30 utils.
Q: Is Rahul in equilibrium? If not, what should he do?
Answer: Let's check the condition: MUc / Pc = 40 / 20 = 2. And MUchips / Pchips = 30 / 10 = 3.
Since MUchips / Pchips > MUc / Pc, he is not in equilibrium. He is getting more utility per rupee from chips. To reach equilibrium, he should consume more chips and fewer chocolates. Difficulty: Hard
13. Read the following case:
During a festival, the price of apples falls drastically, while the consumer's income remains the same.
Q: How will this affect the consumer's budget line?
Answer: Since the price of apples (let's say Good X on the horizontal axis) has fallen, the consumer can now buy more apples with the same income. The budget line will pivot or rotate outwards along the X-axis. The Y-intercept will remain unchanged. Difficulty: Medium
Assertion-Reason Questions
14. Assertion (A): At the point of consumer equilibrium, the Indifference Curve must be concave to the origin.
Reason (R): The law of diminishing marginal rate of substitution operates.
Answer: Assertion (A) is False, but Reason (R) is True. (The IC must be convex, not concave, to the origin at equilibrium). Difficulty: Medium
15. Assertion (A): Total utility falls when marginal utility becomes negative.
Reason (R): Marginal utility is the addition to total utility, so adding a negative value decreases the total.
Answer: Both (A) and (R) are True, and (R) is the correct explanation of (A). Difficulty: Easy
❌ Common Mistakes Students Make
Exam checking uncovers some very common blunders. Avoid these to score full marks:
- Confusing the conditions: Students often mix up the single commodity condition (
MUx = Px) with the two-commodity condition (MUx / Px = MUy / Py). Don't mix them up! - Forgetting to write 'diminishing MRS': When asked why IC is convex, simply writing "because of MRS" is incomplete. You must write Diminishing Marginal Rate of Substitution.
- Mixing up Utility and Indifference approaches: Utility approach is 'Cardinal' (numbers like 10 utils). Indifference curve is 'Ordinal' (ranking). Examiners deduct marks if you mix their assumptions.
- Diagram Errors: When drawing the tangency point for consumer equilibrium, make sure the IC only touches the budget line, it should not cross or intersect it.
💡 Exam Preparation Tips for 2026
- Master the Formulas: Write down equations like
TU = ΣMU,PxX + PyY = M, and the equilibrium conditions on a sticky note and paste it near your study table. - Draw Clean Diagrams: Economics is a visual subject. A neat diagram for the Indifference Map or TU-MU relationship will fetch you more marks than long paragraphs. Always label your X and Y axes!
- Practice MRS Calculations: Numerical questions where you have to calculate MRS from a given schedule are very common in boards and CUET.
- Last-Minute Strategy: Focus heavily on the properties of Indifference Curves and the conditions for Consumer Equilibrium. These are guaranteed 4 to 6 mark questions.
🧠 Chapter 2 Interactive Quiz (Test Your Knowledge)
Revise fatafat with these quick conceptual MCQs!
1. Utility is a ________ concept.
2. At the point of satiety (maximum satisfaction), Marginal Utility is:
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Q: An Indifference Curve is convex to the origin because of:
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❓ FAQ Section
1. Is Class 11 Microeconomics Chapter 2 important for CUET 2026?
2. Where can I get the NCERT PDF Download for Chapter 2 Microeconomics?
3. What is the difference between cardinal and ordinal utility?
4. Why does MU become negative?
5. Which questions from Chapter 2 are most important for boards?
Conclusion
Mastering Consumer's Equilibrium might feel tricky at first, but once you grab the logic behind the formulas and curves, it becomes super easy. Make sure you revise these NCERT solutions regularly, practice your diagrams, and try solving Previous Year Questions (PYQs). Don't forget to download the notes and save this page.
Keep your focus sharp, bina kisi tension ke padhai karo, and get ready to ace your 2026 Board exams!