GSEB Class 11 Economics Solutions Chapter 3 Demand

GSEB Solutions Class 11 Economics Chapter 3 Demand

1. Choose Correct Option For The Following From The Options Provided :

Question 1. Factors affecting demand can be classified into how many categories?
(A) One
(B) Two
(C) Three
(D) Four
Answer: (B) Two
In simple words: Demand-influencing factors are divided into two main groups.

🎯 Exam Tip: Classifying demand determinants into broad categories is fundamental for understanding market dynamics.

 

Question 2. How is the demand curve sloped?
(A) Negative
(B) Positive
(C) Parallel to X-axis
(D) Y-axis
Answer: (A) Negative
In simple words: A demand curve usually slopes downwards, indicating an inverse relationship.

🎯 Exam Tip: A downward-sloping demand curve illustrates the law of demand where price and quantity demanded move in opposite directions.

 

Question 3. What is the other name for poor quality commodities?
(A) Prestigious commodities
(B) Very cheap commodities
(C) Giffen commodities
(D) Useless commodities
Answer: (C) Giffen commodities
In simple words: Giffen goods are another term for low-quality products.

🎯 Exam Tip: Understanding Giffen goods is crucial as they are an exception to the law of demand.

 

Question 4. How many types of price elasticity of demand are there?
(A) Two
(B) Four
(C) Five
(D) Seven
Answer: (B) Four
In simple words: There are four main ways to measure how much demand changes with price.

🎯 Exam Tip: Knowing the different types of price elasticity helps in analyzing consumer response to price changes.

 

Question 5. What is the relationship between price and demand?
(A) Positive
(B) Inverse
(C) Equal
(D) Zero
Answer: (B) Inverse
In simple words: Price and demand usually move in opposite directions.

🎯 Exam Tip: The inverse relationship between price and demand is the core principle of the Law of Demand.

 

Question 6. Which kind of commodities are called complementary commodities?
(A) Joint
(B) Competitive
(C) Not related
(D) Alternative
Answer: (A) Joint
In simple words: Products used together are called complementary or joint commodities.

🎯 Exam Tip: Understanding complementary goods helps in analyzing how the demand for one good affects another.

 

Question 7. What is the movement of demand curve when demand expands?
(A) Upward
(B) Downward
(C) Right side on another demand curve
(D) Left side on another demand curve
Answer: (B) Downward
In simple words: Demand expansion means the movement on the curve is downwards.

🎯 Exam Tip: Expansion and contraction of demand involve movement *along* the existing demand curve.

 

Question 8. Which one has no relation with demand curve?
(A) Specific time
(B) Specific price
(C) Consumer
(D) Supply
Answer: (D) Supply
In simple words: Supply is not a factor depicted on a demand curve.

🎯 Exam Tip: A demand curve illustrates the relationship between price and quantity demanded, not supply.

 

Question 9. Who has presented law of demand?
(A) Adam Smith
(B) Alfred Marshall
(C) Robbins
(D) Keynes
Answer: (B) Alfred Marshall
In simple words: Alfred Marshall is credited with presenting the Law of Demand.

🎯 Exam Tip: Remembering key economists and their contributions is important in economics.

 

Question 10. When products are expensive then how is the demand of prestigious goods of the rich?
(A) More
(B) Less
(C) Zero
(D) Negative
Answer: (A) More
In simple words: Rich people often demand more prestigious goods when they are expensive.

🎯 Exam Tip: Prestigious goods are an exception to the law of demand, as higher prices can sometimes increase their desirability.

2. Answer The Following Questions In One Sentence :

 

Question 1. What is demand?
Answer: Demand refers to the specific amount of a good or service that a consumer wishes, possesses the financial capacity, and is prepared to acquire at a particular price during a defined period.
In simple words: Demand is how much of something people want and can afford to buy at a certain price and time.

🎯 Exam Tip: A complete definition of demand requires including desire, ability to pay, willingness to pay, price, and time.

 

Question 2. What is income elasticity of demand?
Answer: Income elasticity of demand measures the responsiveness or degree to which the quantity demanded of a good changes in relation to a change in a consumer's income. It is calculated as the proportionate change in demand divided by the proportionate change in income.
\( \text{Income elasticity (E}_y) = \frac{\text{Proportionate change in demand}}{\text{Proportionate change in income}} \)
In simple words: Income elasticity shows how much people change what they buy when their income goes up or down.

🎯 Exam Tip: Income elasticity helps classify goods as normal, inferior, or luxury, based on how their demand reacts to income changes.

 

Question 3. What is cross elasticity of demand?
Answer: Cross elasticity of demand, also known as cross-price elasticity, quantifies how the demand for a particular commodity alters due to a price change in a related good (which can be either a substitute or a complementary item). The value of this elasticity can be positive or negative, reflecting whether the goods are substitutes or complements, respectively.
In simple words: Cross elasticity tells us how the demand for one product changes when the price of another related product (like a substitute or a complement) changes.

🎯 Exam Tip: A positive cross elasticity indicates substitute goods, while a negative one indicates complementary goods.

 

Question 4. When is there possibility of expansion - contraction of demand?
Answer: Expansion or contraction of demand occurs when the price of a good changes (either falling or rising), provided that all other influencing factors remain unchanged.
In simple words: Demand expands when price falls and contracts when price rises, assuming nothing else changes.

🎯 Exam Tip: Expansion and contraction represent movements *along* the demand curve, driven solely by price changes.

 

Question 5. In which situation does demand decrease or increase?
Answer: An increase or decrease in demand happens when consumers alter their demand for a good (either raising or lowering it) due to factors other than its own price, while the price itself stays constant.
In simple words: Demand increases or decreases when non-price factors cause people to buy more or less of a product, even if its price stays the same.

🎯 Exam Tip: An increase or decrease in demand leads to a *shift* of the entire demand curve, caused by non-price determinants.

 

Question 6. Why is the law of demand called as conditional law?
Answer: The law of demand is termed a conditional law because its validity depends on the assumption that all factors affecting demand, apart from the commodity's own price, are held constant.
In simple words: The law of demand only works if other things, besides price, don't change.

🎯 Exam Tip: The 'ceteris paribus' assumption (all other things being equal) is fundamental to the Law of Demand.

3. Answer The Following Questions In Short :

 

Question 1. What is demand function?
Answer: A demand function mathematically represents the cause-and-effect relationship between the quantity demanded of a good and the various factors that influence it. Essentially, it illustrates how the demand for a product is determined by multiple variables, including its own price (\(P_x\)), consumer tastes and preferences (\(T\)), consumer income (\(Y\)), prices of related goods (\(P_y\)), future price expectations (\(P_e\)), and demographic factors (\(U\)). The general mathematical form is given by \(D_x = f(P_x, P_y, P_e, T, Y, U)\).
In simple words: A demand function is a mathematical way to show how many factors like price, income, and preferences affect how much of a product people want to buy.

🎯 Exam Tip: Clearly stating the components of the demand function and their symbols is crucial for a comprehensive answer.

 

Question 2. What is substitution effect?
Answer: The substitution effect describes the phenomenon where, if the price of a particular good decreases, it becomes comparatively more affordable than its substitute products. Consequently, consumers tend to reduce their consumption of the now relatively more expensive substitute goods and instead increase their demand for the good whose price has fallen. For instance, if cotton pants become cheaper while denim pants remain the same price, consumers are likely to substitute denim with cotton, leading to an increased demand for cotton pants.
In simple words: When one product's price drops, people buy more of it because it's now cheaper than similar alternatives; this shift is the substitution effect.

🎯 Exam Tip: Illustrating the substitution effect with a relevant example helps demonstrate a clear understanding of the concept.

 

Question 3. What is meant by Giffen goods?
Answer: Giffen goods are a specific type of inferior good where, contrary to the law of demand, a decrease in their price actually leads to a reduction in their consumption, and vice versa. This occurs because when the price of an inferior good falls, the consumer's real income effectively increases, allowing them to afford superior quality goods instead. Robert Giffen first observed and described this phenomenon. These goods are typically necessities bought by lower-income groups. For example, if the price of staple grains like Jowar or Bajra falls significantly, a low-income consumer might feel wealthier and choose to buy less of these inferior grains and more of a superior grain like wheat. Other examples include vegetable ghee versus pure ghee.
In simple words: Giffen goods are cheap necessities where people buy less of them if their price falls because they can then afford better alternatives.

🎯 Exam Tip: Giffen goods are a critical exception to the law of demand, often confused with inferior goods; highlight their unique price-demand relationship.

 

Question 4. What is individual demand?
Answer: Individual demand refers to the quantity of a specific good that a single consumer is willing and able to purchase at a particular price within a definite timeframe.
In simple words: Individual demand is how much one person wants to buy of a product at a certain price at a specific time.

🎯 Exam Tip: Differentiating between individual and market demand is fundamental to understanding aggregate demand.

 

Question 5. What is market demand?
Answer: Market demand represents the aggregate sum of all individual demands from every consumer present in a market for a specific good, at a given price, and within a particular period. It is essentially the total quantity of a good that all consumers collectively are willing and able to purchase. This aggregate demand is typically derived by summing up the individual demands of all buyers, often illustrated through tables and diagrams that combine separate consumer demands into a single market demand curve.
In simple words: Market demand is the total amount of a product that all buyers in a market want to buy at a certain price and time.

🎯 Exam Tip: Market demand is the horizontal summation of all individual demand curves at each price level.

 

Question 6. What is price elasticity of demand?
Answer: Price elasticity of demand (\( \varepsilon_p \)) is an economic measure that quantifies the responsiveness of the quantity demanded of a good to a change in its price. While the law of demand indicates an inverse relationship between price and quantity demanded, price elasticity specifies the *degree* or *proportion* by which demand changes. As defined by Marshall, it reflects how much demand expands when price falls and how much it contracts when price rises. For instance, if a 1% fall in the price of good 'X' results in a 5% rise in its demand, the price elasticity is calculated as the ratio of the percentage change in demand for X to the percentage change in price of X.
\( \text{E}_p = \frac{\text{Percentage change in demand for X}}{\text{Percentage change in price of X}} \)
If the price of good 'X' falls by 1% and its demand rises by 5%, the elasticity would be \( \frac{+5\%}{-1\%} = |5| \) or 5. Price elasticity of demand (\( \varepsilon_p \)) is a pure, unitless number, meaning it has no units like %, kg, or meters.
In simple words: Price elasticity of demand tells us how much the quantity people buy changes when the price of an item goes up or down. It's a number that shows responsiveness without specific units like percentages or weights.

🎯 Exam Tip: Price elasticity is crucial for businesses to understand how pricing strategies will affect their sales revenue.

 

Question 7. Which commodities are called prestigious commodities?
Answer: Prestigious commodities, also known as Veblen goods, are high-priced items typically consumed by affluent individuals as symbols of status and wealth. Examples include expensive jewelry, luxury cars, and high-end mobile phones. Their demand often increases with price, contrary to the law of demand, as their expensiveness enhances their desirability as status symbols.
In simple words: Prestigious commodities are expensive items bought by rich people to show off their status, and their demand can even go up when prices rise.

🎯 Exam Tip: Prestigious goods represent an exception to the law of demand, as their value is tied to their high price and exclusivity.

 

Question 8. State the names of methods to measure price elasticity of demand.
Answer: The methods used to categorize or measure price elasticity of demand can be classified into five primary types:
1. Perfectly elastic demand (\( \text{E}_p = \infty \))
2. Perfectly inelastic demand (\( \varepsilon_p = 0 \))
3. Unitary (unit) elastic demand (\( \text{E}_p = 1 \))
4. Relatively elastic demand (\( \varepsilon_p > 1 \))
5. Relatively inelastic demand (\( \varepsilon_p < 1 \))
In simple words: There are five main ways to classify how demand reacts to price changes: perfectly elastic, perfectly inelastic, unitary elastic, relatively elastic, and relatively inelastic.

🎯 Exam Tip: Students should know the definitions and implications of each type of price elasticity for both consumer behavior and business strategy.

4. Answer The Following Questions In Brief Points :

 

Question 1. Define income effect and substitution effect.
Answer:
(1) Income effect: This refers to the change in the quantity demanded of a good due to a change in the consumer's real income, which occurs when the price of a good alters while nominal income stays constant. For example, if the price of a good drops, a consumer's purchasing power (real income) increases, allowing them to acquire more of that good, thus potentially boosting its demand.
(2) Substitution effect: This effect describes how a consumer shifts their consumption patterns when the relative price of a good changes. If a good's price falls, it becomes comparatively less expensive than its alternatives, prompting consumers to substitute other goods with this now cheaper item, thereby increasing its demand.
In simple words:
Income effect: When a product's price changes, your buying power changes, making you buy more or less of it.
Substitution effect: When a product's price changes, you switch to or from it because it's now cheaper or more expensive compared to similar products.

🎯 Exam Tip: These two effects combine to explain the overall change in quantity demanded following a price change, forming the basis of consumer theory.

 

Question 2. Explain expansion and contraction of demand along with diagram.
Answer: Expansion and contraction of demand refer to movements along a single demand curve, occurring solely due to changes in the commodity's own price, while all other determinants of demand remain constant. Specifically, demand expands when the price decreases, leading to a greater quantity demanded. Conversely, demand contracts when the price increases, resulting in a smaller quantity demanded.

Let us take an example to understand the expansion and contraction of demand:

Price of the commodity (in Rs.)	Demand of the commodity (in units)	Note
5	1	Demand contracts due to rise in price
4	2
3	3
2	4	Demand expands due to fall in price
1	5

ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र मांग के विस्तार और संकुचन को दर्शाता है। इसमें Y-अक्ष पर वस्तु की कीमत (रुपये में) और X-अक्ष पर वस्तु की मांग (इकाइयों में) दिखाई गई है। 'DD' एक नीचे की ओर ढलान वाला मांग वक्र है। बिंदु 'a' प्रारंभिक संतुलन दर्शाता है। जब कीमत बढ़ती है, तो मांग घटती है, जिसे बिंदु 'a' से 'b' की ओर 'मांग का संकुचन' कहा जाता है। जब कीमत घटती है, तो मांग बढ़ती है, जिसे बिंदु 'a' से 'c' की ओर 'मांग का विस्तार' कहा जाता है। यह वक्र पर गति को दर्शाता है, न कि वक्र के बदलाव को।
Initially, at a price of Rs. 3, the quantity demanded is 3 units, represented by point 'a' on the demand curve.
**Expansion:** When the price decreases to Rs. 1, the demand expands to 5 units, indicated by point 'c' on the diagram. This movement from 'a' downwards to 'c' along the demand curve DD is termed expansion of demand, occurring because of the price reduction shown on the Y-axis.
**Contraction:** Conversely, if the initial price of Rs. 3 increases to Rs. 5, the demand contracts from 3 units to 1 unit, depicted by point 'b'. This upward movement from 'a' to 'b' along the same demand curve DD is called contraction of demand, reflecting the price increase on the Y-axis. Both expansion and contraction are movements along the existing demand curve; expansion is a downward movement, and contraction is an upward movement.
In simple words: Expansion means buying more when the price drops, moving down the demand curve. Contraction means buying less when the price goes up, moving up the demand curve.

🎯 Exam Tip: Distinguish carefully between movement *along* the demand curve (expansion/contraction due to price) and *shifts* of the demand curve (increase/decrease due to non-price factors).

 

Question 3. Explain increase and decrease of demand and represent it diagramatically.
Answer: An increase or decrease in demand signifies a shift of the entire demand curve, occurring when the commodity's price remains constant, but other determinants of demand (non-price factors) change. When these non-price factors cause demand to rise at the same price, the demand curve shifts rightward (an increase in demand). Conversely, if these non-price factors lead to a fall in demand at the same price, the demand curve shifts leftward (a decrease in demand). In diagrams, price is typically on the Y-axis and demand on the X-axis, and changes in demand at a fixed price result in these horizontal shifts of the curve.

Let us take an example to understand the increase and decrease in demand:

Price of the commodity (in Rs.)	Demand of the commodity (in units)	Note
3	1	Decrease in demand
3	2
3	3
3	4	Increase in demand
3	5

ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र मांग में वृद्धि और कमी को दर्शाता है। Y-अक्ष पर वस्तु की कीमत (रुपये में) और X-अक्ष पर वस्तु की मांग (इकाइयों में) है। मूल मांग वक्र \(D_1D_1\) है, जिस पर बिंदु 'a' (कीमत Rs. 3, मांग 3 इकाइयाँ) दर्शाया गया है। जब कीमत स्थिर रहती है लेकिन अन्य कारकों से मांग बढ़ती है, तो वक्र \(D_3D_3\) पर बिंदु 'c' (कीमत Rs. 3, मांग 5 इकाइयाँ) की ओर दाईं ओर खिसक जाता है, जो मांग में वृद्धि को दर्शाता है। इसके विपरीत, यदि कीमत स्थिर रहने पर अन्य कारकों से मांग घटती है, तो वक्र \(D_2D_2\) पर बिंदु 'b' (कीमत Rs. 3, मांग 1 इकाई) की ओर बाईं ओर खिसक जाता है, जो मांग में कमी को दर्शाता है।
The initial demand is shown by demand curve \(D_1D_1\), with point 'a' representing 3 units of demand at a price of Rs. 3.
**Increase in Demand:** If the price stays at Rs. 3 but demand rises to 5 units due to other factors, the demand curve shifts rightward to \(D_3D_3\), moving from point 'a' to point 'c'.
**Decrease in Demand:** If the price remains at Rs. 3 but demand falls to 1 unit because of other factors, the demand curve shifts leftward to \(D_2D_2\), moving from point 'a' to point 'b'. Therefore, an increase in demand is characterized by a rightward shift of the demand curve, and a decrease in demand by a leftward shift.
In simple words: Increase in demand means the whole curve moves right (people buy more at the same price), and decrease means it moves left (people buy less at the same price).

🎯 Exam Tip: Shifts in the demand curve are crucial for understanding market dynamics as they reflect changes in consumer preferences, income, or prices of related goods, not just the product's own price.

 

Question 4. Explain income elasticity of demand.
Answer: Income elasticity of demand (\( \varepsilon_y \)) is a valuable metric for assessing how the demand for a product changes in response to alterations in a consumer's income. It measures the degree to which quantity demanded shifts due to income fluctuations. The formula for income elasticity is the proportionate change in demand divided by the proportionate change in income.
\( \text{Income elasticity (E}_y) = \frac{\text{Proportionate change in demand}}{\text{Proportionate change in income}} \)
This elasticity can be classified into several types:
(1) Positive income elastic demand: This occurs for normal goods, where demand increases as income rises. It includes:
(A) Unit income elastic demand (\( \varepsilon_y = 1 \))
(B) Elasticity of demand greater than unity (\( \varepsilon_y > 1 \))
(C) Elasticity of demand less than unity (\( \varepsilon_y < 1 \))
(2) Negative income elastic demand: This applies to inferior goods, where demand decreases as income rises.
(3) Zero income elastic demand: This is for goods whose demand is unresponsive to income changes.
In simple words: Income elasticity measures how sensitive a product's demand is to changes in people's income, categorizing goods as normal, inferior, or having no income effect.

🎯 Exam Tip: Understanding the different types of income elasticity is crucial for businesses to segment markets and forecast sales based on economic growth or recession.

 

Question 5. Explain the exceptions to the law of demand.
Answer: The law of demand, which posits an inverse relationship between price and quantity demanded, has several exceptions where this relationship does not hold true. These exceptions include:
(1) Prestigious Goods: These are luxury items whose demand increases with price because they serve as status symbols for the wealthy (e.g., high-end cars, designer jewelry).
(2) Extremely Low-Priced Goods: For goods that are very cheap and constitute a tiny fraction of a consumer's budget (e.g., pins, toffees), changes in price may not significantly affect demand, as consumers may not buy much more even if prices fall.
(3) Giffen Goods: These are specific inferior goods where a fall in price leads to a decrease in demand because the consumer's increased real income allows them to switch to superior alternatives (e.g., certain staple grains).
(4) Special Preferences of People: Consumers who develop a strong habit or preference for certain brands or goods may maintain their demand even if prices rise, due to brand loyalty or personal attachment.
In simple words: Exceptions to the law of demand include luxury items (more expensive means more desired), very cheap goods (price changes don't matter much), Giffen goods (cheaper means less desired), and preferred brands (people buy them no matter what).

🎯 Exam Tip: Identifying and explaining these exceptions demonstrates a nuanced understanding of consumer behavior beyond the basic law of demand.

5. Answer The Following Questions In Detail :

 

Question 1. Explain individual demand and market demand along with diagrams.
Answer: In economics, demand can be broadly classified into two main parts:
1. Individual demand: Individual demand refers to the quantity of a specific good that a single consumer is willing and able to purchase at a particular price within a definite timeframe.
2. Market demand: Market demand represents the aggregate sum of all individual demands from every consumer present in a market for a specific good, at a given price, and within a particular period. It is essentially the total quantity of a good that all consumers collectively are willing and able to purchase. This aggregate demand is typically derived by summing up the individual demands of all buyers. The table below shows individual demand for customers A, B, and C, with the last column representing the summated market demand. The first three diagrams depict individual demand for each customer, while the fourth illustrates their combined market demand.

Price of the commodity (in Rs.)	Demand of person A (in units)	Demand of person B (in units)	Demand of person C (in units)	Market demand i.e. Total demand of A, B and C (in units)
10	1	2	3	6
8	2	3	4	9
6	3	4	5	12
4	4	5	6	15
2	5	6	7	18

ℹ️ चित्र व्याख्या (Diagram Explanation): इस खंड में, Y-अक्ष पर वस्तु की कीमत (रुपये में) और X-अक्ष पर वस्तु की मांग (इकाइयों में) दर्शाई गई है। इसमें चार मांग वक्र शामिल हैं: व्यक्ति A, व्यक्ति B, व्यक्ति C के लिए व्यक्तिगत मांग वक्र, और इन तीनों की कुल मांग को दर्शाने वाला बाजार मांग वक्र। प्रत्येक व्यक्तिगत मांग वक्र नीचे की ओर ढलान वाला है, जो कीमत और मांग के बीच विपरीत संबंध दर्शाता है। बाजार मांग वक्र भी नीचे की ओर ढलान वाला है, जो सभी व्यक्तिगत मांगों के योग को दर्शाता है।
Since demand curves for individual customers A, B, and C are all downward sloping, the market demand curve, which is their summation, also slopes downwards.
In simple words: Individual demand is what one person wants to buy, while market demand is the total of what all people in a market want to buy.

🎯 Exam Tip: Market demand curves are derived by horizontally summing individual demand curves, reflecting the collective behavior of consumers.

Price of the commodity (in Rs.)	Demand of person A (in units)	Demand of person B (in units)	Demand of person C (in units)	Market demand i.e. Total demand of A, B and C (in units)
10	1	2	3	6
8	2	3	4	9
6	3	4	5	12
4	4	5	6	15
2	5	6	7	18

ℹ️ चित्र व्याख्या (Diagram Explanation): यह आरेख व्यक्ति A की मांग वक्र को दर्शाता है। इसमें Y-अक्ष पर वस्तु की कीमत (Rs. में) और X-अक्ष पर वस्तु की मांग (इकाइयों में) दिखाई गई है। वक्र 'D1D1' नीचे की ओर झुका हुआ है, जो कीमत और मांग के बीच विपरीत संबंध को दर्शाता है।
ℹ️ चित्र व्याख्या (Diagram Explanation): यह आरेख व्यक्ति B की मांग वक्र को दर्शाता है। इसमें Y-अक्ष पर वस्तु की कीमत (Rs. में) और X-अक्ष पर वस्तु की मांग (इकाइयों में) दिखाई गई है। वक्र 'D2D2' नीचे की ओर झुका हुआ है, जो कीमत में कमी के साथ मांग में वृद्धि को प्रदर्शित करता है।
ℹ️ चित्र व्याख्या (Diagram Explanation): यह आरेख व्यक्ति C की मांग वक्र को दर्शाता है। इसमें Y-अक्ष पर वस्तु की कीमत (Rs. में) और X-अक्ष पर वस्तु की मांग (इकाइयों में) दिखाई गई है। वक्र 'D3D3' नीचे की ओर झुका हुआ है, जो यह बताता है कि कीमत बढ़ने पर व्यक्ति C की मांग घटती है।
ℹ️ चित्र व्याख्या (Diagram Explanation): यह आरेख बाजार मांग वक्र को दर्शाता है, जो व्यक्तियों A, B और C की व्यक्तिगत मांगों का कुल योग है। इसमें Y-अक्ष पर वस्तु की कीमत (Rs. में) और X-अक्ष पर वस्तु की बाजार मांग (इकाइयों में) दिखाई गई है। वक्र 'D4D4' भी नीचे की ओर ढलान वाला है, जो दर्शाता है कि बाजार में भी कीमत और मांग के बीच विपरीत संबंध होता है।

Conclusion:
Since individual demand curves for all customers (A, B, and C) exhibit a downward slope, the overall market demand curve will also slope downwards.

Question 2. Define demand and explain factors affecting demand.
Answer:
Demand:
The quantity of a commodity that a buyer wishes, is capable of, and is willing to purchase at a specified price and time is referred to as demand.
The determination of demand for a commodity or service relies on five key factors:
1. Desire for the commodity.
2. Willingness to acquire it.
3. Ability to pay for it.
4. A specific price point.
5. A particular time frame.
All these five elements are crucial for defining demand accurately.
Factors influencing demand, also known as determinants of demand for a commodity or service, can be categorized into two main groups:
(I) Price of the commodity/service
(II) Factors other than price (i.e., other determinants)
(I) Price of a commodity/service:
• The price of a good represents its most critical determinant.
• When a good's price decreases, a discerning consumer typically buys more, leading to an expansion in demand. Conversely, if the price rises, consumers buy less, causing demand to contract.
(II) Other determinants:
1. Consumer Tastes and Preferences:
• Demand is significantly influenced by a consumer's tastes and preferences.
• Tastes and preferences are linked to a consumer's likes and dislikes, along with various factors such as age, prevailing trends, and so forth.
Example:
• If an individual enjoys reading, their preference for reading materials will change with age.
• During youth, a person might prefer story books; in adolescence, novels become more appealing; and in old age, spiritual books may be favored.
2. Consumer Income:
• The demand for a commodity generally rises with an increase in consumer income.
• Similarly, when income declines, the demand for a good also falls. Thus, a direct relationship exists between income and demand.
• However, for certain goods, known as inferior goods, this direct relationship does not apply.
• In economic terms, an inferior good is one whose demand declines when consumer income increases, or whose demand increases when consumer income decreases.
Example of inferior goods/services:
For instance, inter-city bus travel is often a less expensive (inferior) option compared to air or rail travel, but it is more time-consuming. When a consumer has limited funds, they prefer bus travel, leading to higher demand for it. However, if their income increases, they tend to opt for quicker and more comfortable transport systems like private cars or air travel, resulting in a decrease in demand for bus travel.
3. Prices of Related Goods:
Goods like french-fries and ketchup, which are closely associated, are termed related goods. The price of related goods is another key factor affecting demand.
Related goods are categorized as either
1. Substitute goods or
2. Complementary goods.
The demand for a specific good is contingent on the price and availability of its related goods, including substitutes and complements. For example, if the price of french-fries doubles, the demand for ketchup may decrease.
4. Expectations about Future Prices:
A consumer's anticipation regarding the future price of a good influences their current demand for that good. If a consumer expects the price of a good to rise in the future, their current demand for that good increases, and vice-versa.
5. Population Size and Demographic Profile:
• The size and demographic makeup of a population significantly impact the overall market demand for a good.
• If a region has a large population, the total market demand will be greater, and vice-versa. Similarly, if a majority of the population belongs to a specific age-group, the demand for certain goods in that market segment will be higher.
• For instance, a café located near colleges will experience higher demand due to a large concentration of young people.
In simple words: Demand is the quantity of a product consumers are willing and able to buy at a certain price and time. It is primarily affected by the product's price, consumer income, prices of related goods, expectations about future prices, and population demographics.

🎯 Exam Tip: When defining demand, ensure all five elements (desire, willingness, ability, price, and time) are included. For factors affecting demand, structure your answer clearly under "price" and "other determinants" for maximum clarity and score.

Question 3. Explain law of demand with the help of schedule and diagram.
Answer:
Demand schedule:
• A demand schedule is a tabular representation that illustrates a consumer's willingness to purchase varying quantities of a good at different prices.
• The graphical depiction of a demand schedule is known as a demand curve.
Example:
The table below provides an illustrative example of a demand schedule.

Price of milk (in Rs.)	Demand of milk (in litres)
50	1
40	2
30	3
20	4
10	5

ℹ️ चित्र व्याख्या (Diagram Explanation): यह आरेख मांग के नियम को दर्शाता है। Y-अक्ष पर दूध की कीमत (Rs. में) और X-अक्ष पर दूध की मांग (लीटर में) दर्शायी गई है। वक्र 'DD' एक नीचे की ओर झुकी हुई रेखा है, जो कीमत और मांग के बीच विपरीत संबंध को स्पष्ट रूप से प्रस्तुत करती है।

Diagram for law of demand
The schedule (table) indicates varying prices of milk and the corresponding demand at those prices.
• The data from the schedule is plotted on a graph to derive a demand curve.
• The price of milk, acting as the independent variable, is plotted on the Y-axis, while the demand for milk, which is dependent on price, is plotted on the X-axis.
Demand curve:
• By plotting the demand at various prices as specified in the schedule, we obtain points 'a', 'b', 'c', 'd', and 'e'. These plotted points illustrate the various price-demand combinations.
• Connecting these points yields the demand curve 'DD'. This curve slopes downwards from left to right, indicating an inverse relationship between price and demand.
Explanation of the demand curve:
At point 'a', the price of milk is Rs. 50, and the demand is 1 litre. At point 'b', when the price decreases to Rs. 40, the demand increases to 2 litres. Similarly, at point 'e', when the price falls to as low as Rs. 10, the demand expands significantly to 5 litres.
Analysis/Conclusion:
Price and demand exhibit an inverse relationship; specifically, when price increases, demand decreases, and vice-versa.
• This inverse relationship is explained by two primary reasons:
1. Income effect and
2. Substitution effect.
In simple words: The Law of Demand states that as the price of a good rises, its quantity demanded falls, and vice-versa, assuming all other factors remain constant. This is shown in a demand schedule (table) and a downward-sloping demand curve.

🎯 Exam Tip: When explaining the law of demand, ensure you provide both a numerical schedule (table) and a clearly labeled diagram. The explanation should detail how a change in price leads to a change in quantity demanded, highlighting the inverse relationship.

Question 4. Define price elasticity of demand and explain its types with diagrams.
Answer:
Price elasticity of demand:
• Price elasticity of demand is a measure that quantifies the proportionate (extent) to which demand changes in response to a change in price. It is denoted by \(\epsilon_p\).
• According to Marshall, the degree of elasticity of demand depends on the extent of demand increase due to a price fall, and the extent of demand decrease due to a price rise.
• Price elasticity of demand \( (\epsilon_p) = \frac{\text { Proportionate change in demand }}{\text { Proportionate change in price }} \)
Perfectly inelastic demand \( (\epsilon_p = 0) \):
• Perfectly inelastic demand is the opposite of perfectly elastic demand.
• When the price of a commodity, for instance, commodity 'K', changes by any amount (e.g., 10%), but there is absolutely no change in its demand, then such demand is termed perfectly inelastic demand.
\[ \epsilon_p = \frac{\text { Proportionate change in demand }}{\text { Proportionate change in price }} \]
\[ = \frac{0 \%}{+10 \%} = 0 \text{ (zero)} \]
• In the case of perfectly inelastic demand, the price elasticity, i.e., \(\epsilon_p = 0\).
• As illustrated in the diagram, the demand curve 'DD' is a vertical straight line parallel to the Y-axis. This curve indicates that regardless of price fluctuations, the demand remains constant. Such demand elasticity is always zero.

ℹ️ चित्र व्याख्या (Diagram Explanation): यह आरेख पूर्णतया बेलोचदार मांग को दर्शाता है। Y-अक्ष पर वस्तु की कीमत और X-अक्ष पर वस्तु की मांग दर्शायी गई है। मांग वक्र 'DD' Y-अक्ष के समानांतर एक सीधी खड़ी रेखा है, जो यह संकेत देती है कि कीमत में किसी भी परिवर्तन के बावजूद मांग स्थिर रहती है।

Unitary elastic demand \( (\epsilon_p = 1) \):
• Unitary elastic demand occurs when the percentage (proportionate) change in demand is precisely equal to the percentage (proportionate) change in price.
• For example, if the price of commodity 'S' falls by 5% and its demand also changes by 5%, then it is considered unitary elastic demand.
\[ \epsilon_p = \frac{\text { Proportionate change in demand }}{\text { Proportionate change in price }} \]
\[ = \frac{+5 \%}{-5 \%} = |1| \]
• In unitary elastic demand, the price elasticity is \( \epsilon_p = 1 \).
As depicted in the diagram, on the demand curve 'DD', when the price falls by amount PP\(_1\), demand expands by amount MM\(_1\). Notably, PP\(_1\) = MM\(_1\).

ℹ️ चित्र व्याख्या (Diagram Explanation): यह आरेख एकात्मक बेलोचदार मांग को दर्शाता है। Y-अक्ष पर वस्तु की कीमत और X-अक्ष पर वस्तु की मांग दर्शायी गई है। मांग वक्र 'DD' से पता चलता है कि जब कीमत PP1 मात्रा से गिरती है, तो मांग MM1 मात्रा से बढ़ती है, और ये दोनों परिवर्तन आनुपातिक रूप से बराबर होते हैं, जिससे मांग की एकात्मक लोच प्रदर्शित होती है।

Relatively elastic demand \( (\epsilon_p > 1) \):
1. When price elasticity, i.e., \(\epsilon_p > 1\), it is termed relatively elastic demand. This occurs when a percentage change in demand is proportionally greater than the percentage change in price.
2. This type of elasticity is typically observed for luxury goods, such as televisions and cars. For instance, if the price of commodity 'R' rises by 10% and its demand consequently falls by 30%, then its demand is classified as relatively elastic.
\[ \epsilon_p = \frac{\text { Proportionate change in demand }}{\text { Proportionate change in price }} \]
\[ = \frac{-30 \%}{+10 \%} = |3| \]
3. As the calculation shows, a small increase (change) of 10% in price led to a substantial change of 30% in the commodity's demand.
4. In the diagram, on the demand curve DD\(_1\) for the commodity, when price increases by amount PP\(_1\), demand decreases by amount MM\(_1\), which is proportionally greater than the price change.
Relatively inelastic demand \( (\epsilon_p < 1) \):
• When the percentage change in demand is proportionally less than the percentage change in price, such demand is known as relatively inelastic demand.
• For example, if the price of commodity 'G' rises by 20%, and its demand decreases by 5% as a result, then its demand is considered relatively inelastic demand.

ℹ️ चित्र व्याख्या (Diagram Explanation): यह आरेख सापेक्ष रूप से लोचदार मांग को दर्शाता है। Y-अक्ष पर वस्तु की कीमत और X-अक्ष पर वस्तु की मांग दर्शायी गई है। मांग वक्र 'DD' से पता चलता है कि कीमत में PP1 मात्रा की वृद्धि के जवाब में, मांग MM1 मात्रा से गिरती है, जहाँ मांग में आनुपातिक परिवर्तन कीमत में परिवर्तन से काफी अधिक है, जो सापेक्ष लोचदार मांग को इंगित करता है।

• If price elasticity is less than 1 (or between 0 and 1), the demand is termed inelastic, i.e., \(0 < \epsilon_p < 1\).
• This type of elasticity is characteristic of essential daily needs such as food grains, milk, oil, and similar goods.
\[ \epsilon_p = \frac{\text { Proportionate change in demand }}{\text { Proportionate change in price }} \]
\[ = \frac{-5 \%}{+20 \%} = -\frac{1}{4} = |0.25| \]
In the diagram, on demand curve 'DD\(_1\)', when price increases by amount PP\(_1\), demand falls by amount MM\(_1\), which is proportionally lesser than the change in price.
In simple words: Price elasticity of demand measures how much the quantity demanded of a good changes in response to a change in its price. It can be perfectly inelastic (\(\epsilon_p = 0\), demand doesn't change), unitary elastic (\(\epsilon_p = 1\), demand changes proportionally), relatively elastic (\(\epsilon_p > 1\), demand changes more than proportionally), or relatively inelastic (\(\epsilon_p < 1\), demand changes less than proportionally).

🎯 Exam Tip: To score well, ensure you define price elasticity clearly and illustrate each type with a specific numerical example and a well-drawn, labeled diagram. Emphasize the relationship between percentage changes in price and quantity demanded for each elasticity type.