Theory of Consumer Behaviour Class 12 Questions and Answers Explained

Understanding the Basics of Consumer Behaviour in Class 12 Economics

Consumer behaviour studies how individuals decide to spend their money on goods and services to maximise satisfaction. In Class 12 NCERT Economics, this theory explains the choices consumers make under budget constraints.

Key terms to remember:

• Utility: Satisfaction derived from consuming a good or service.
• Consumer Equilibrium: The point where a consumer maximises utility given their budget.
• Budget Line: Represents all combinations of two goods a consumer can afford.

Understanding these basics is essential for answering theory of consumer behaviour class 12 questions and answers effectively.

The Law of Diminishing Marginal Utility Explained

One of the core concepts in consumer behaviour is the Law of Diminishing Marginal Utility. It states that as a consumer consumes more units of a good, the additional satisfaction (marginal utility) from each extra unit decreases.

For example, if you eat one chocolate, you enjoy it a lot, but the fifth chocolate might give you less pleasure.

This law helps explain why consumers diversify their consumption rather than buying unlimited quantities of one good.

Formula:

$$ MU_n < MU_{n-1} $$

where $MU_n$ is the marginal utility of the $n^{th}$ unit.

This concept is frequently tested in Class 12 theory questions.

Cardinal vs Ordinal Utility: Key Differences for Class 12 Students

Understanding utility measurement is crucial. There are two approaches:

Class 12 NCERT questions often ask to distinguish these concepts or apply them in examples.

Budget Constraint and Consumer Equilibrium in Theory of Consumer Behaviour

Consumers face a budget constraint which limits their consumption choices. The budget line equation is:

$$ P_x X + P_y Y = M $$

where:

• $P_x$, $P_y$ = prices of goods X and Y
• $X$, $Y$ = quantities of goods
• $M$ = consumer's income

Consumer equilibrium occurs when the consumer maximises utility subject to this budget. The condition is:

$$ \frac{MU_x}{P_x} = \frac{MU_y}{P_y} $$

This means the marginal utility per rupee spent is equal across all goods.

Worked example:

If $MU_x = 20$, $P_x = 4$, $MU_y = 15$, $P_y = 3$, then:

$$ \frac{20}{4} = 5, \quad \frac{15}{3} = 5 $$

Consumer is in equilibrium.

This concept is a frequent topic in Class 12 questions.

Solved Examples to Practice Theory of Consumer Behaviour Questions

Practicing solved examples helps reinforce concepts:

Example 1: A consumer’s income is ₹100. Price of good A is ₹10 and good B is ₹20. If the consumer buys 5 units of A and 3 units of B, is the consumer within the budget?

Calculation:

Total cost = (5 × 10) + (3 × 20) = 50 + 60 = ₹110

Since ₹110 > ₹100, the consumer exceeds the budget.

Example 2: If the marginal utility of good X is 30 and price is ₹6, and marginal utility of good Y is 24 and price is ₹4, is the consumer in equilibrium?

Calculate marginal utility per rupee:

• $MU_x/P_x = 30/6 = 5$
• $MU_y/P_y = 24/4 = 6$

Since $MU_y/P_y > MU_x/P_x$, consumer should buy more of Y to maximise utility.

These examples clarify how to apply formulas in exam questions.

Tips to Answer Theory of Consumer Behaviour Class 12 Questions Effectively

To score well in theory of consumer behaviour class 12 questions and answers, follow these tips:

• Understand concepts clearly: Avoid rote memorization; focus on logic.
• Use diagrams: Draw budget lines, indifference curves, and utility graphs where applicable.
• Practice NCERT exercises: These are exam-focused and cover common question types.
• Write stepwise answers: For numerical problems, show all calculations.
• Revise key formulas: Like $MU_x/P_x = MU_y/P_y$ and budget line equations.

Consistent practice and conceptual clarity will boost your confidence for the CBSE exam.