A rightward shift in the market demand curve means consumers demand more at every price. Thus, the first event is the shift of the demand curve from DD₀ to DD₂. At the original equilibrium price p₀, the quantity demanded becomes greater than the quantity supplied, creating excess demand. To eliminate this shortage, the market price rises. The higher price encourages firms to supply more while reducing the quantity demanded by consumers. The adjustment continues until a new equilibrium is reached with a higher equilibrium price and a higher equilibrium quantity. Therefore, the correct sequence is: 3 → Market demand curve shifts from DD₀ to DD₂. 2 → Excess demand is observed at the initial price p₀. 1 → Price increases to restore balance. 4 → New equilibrium is established at a higher price and quantity. Hence, Option B is correct.

A leftward shift in the demand curve means consumers demand less at every price. At the original equilibrium price, firms continue supplying the previous quantity, but consumers buy less, creating excess supply (surplus). To clear the surplus, firms reduce prices. As prices fall, quantity demanded increases and quantity supplied decreases until a new equilibrium is established at a lower equilibrium price. Thus: Assertion (A) is true. Reason (R) is also true. Reason (R) correctly explains the assertion. Hence, Option A is correct.

The initial supply equation is: qS = 10 + p A rightward shift of 20 units means producers are willing to supply 20 additional units at every price. Therefore, only the constant term (intercept) increases, while the coefficient of price remains unchanged. Thus, qS = (10 + 20) + p or, qS = 30 + p Hence, Option D is correct.

A leftward shift in the supply curve means firms supply less at every price. At the original equilibrium price, the quantity demanded exceeds the quantity supplied, creating excess demand (shortage). This shortage causes buyers to compete for the limited supply, leading to an increase in the market price. The higher price encourages producers to supply more and consumers to demand less until equilibrium is restored. Therefore, the correct blanks are demand and increase. Hence, Option B is correct.

For normal goods, an increase in consumers' income increases their purchasing power. As a result, consumers are willing and able to purchase more of the good at every possible price. Therefore, the market demand curve shifts rightward, while the supply curve remains unchanged because income is a determinant of demand, not supply. Thus: Option B is correct because demand increases. Option A is incorrect because demand decreases only for inferior goods when income rises. Options C and D are incorrect because income does not directly shift the supply curve.

Consumer income is an important determinant of demand. 1. Normal good (Income rise) → Demand increases because consumers purchase more normal goods as income rises. Therefore, 1 → b (Rightward demand shift). 2. Inferior good (Income rise) → Consumers substitute inferior goods with superior alternatives, so demand decreases. Therefore, 2 → d (Decreased demand). 3. Normal good (Income fall) → Consumers reduce purchases of normal goods, causing a leftward demand shift. Therefore, 3 → a. 4. Fixed supply curve → Consumer income does not directly affect the supply curve. Therefore, 4 → c (Unaffected directly by income). Hence, the correct matching is: 1 → b 2 → d 3 → a 4 → c Therefore, Option C is correct.

An increase in the number of consumers raises the market demand at every price, shifting the demand curve rightward. Statement I is correct because demand increases. Statement II is correct because the number of consumers does not directly influence producers' willingness to supply. Statement III is correct because, with a fixed number of firms, higher demand causes both equilibrium price and equilibrium quantity to increase. Thus, all three statements are correct. Hence, Option A is correct.

The logical sequence begins with an increase in the number of consumers, which raises market demand. As a result: The market demand curve shifts rightward. At the original price, excess demand develops. The shortage pushes the market price upward. Since the supply curve itself does not shift, firms respond by supplying more along the existing supply curve, resulting in a higher equilibrium quantity. Thus, the correct order is: 3 → Number of consumers increases 1 → Demand curve shifts right 2 → Excess demand raises price 4 → Firms supply more along the existing supply curve Hence, Option D is correct.

The Assertion (A) is true because an increase in input prices raises firms' production costs. As production becomes more expensive, firms supply less at every price, shifting the supply curve leftward. The Reason (R) is false because input prices affect producers' costs, not consumers' willingness to buy the final product. Consumer demand depends on factors such as income, tastes, and prices of related goods. Therefore: Assertion (A): True Reason (R): False Hence, Option B is correct.

When the price of an input increases, firms incur higher production costs. Consequently, the marginal cost (MC) of producing each additional unit increases. Since production becomes more expensive, firms are willing to supply less output at every price, resulting in a leftward shift of the supply curve. Thus, the blanks are: Marginal cost increases. Market supply becomes less than before. Therefore, Option C is correct.

Under free entry and exit, existing firms earning supernormal profits attract new firms into the market. As new firms enter, the market supply curve shifts rightward, causing the equilibrium price to fall. This process continues until firms no longer earn supernormal profits. In the long-run equilibrium, firms earn only normal profit, where: Price = Minimum Average Cost (Min AC) At this point, there is no incentive for new firms to enter or existing firms to exit. Therefore, Option C is correct.

Initially, the market demand function is: qD = 200 − p At p = 20, qD = 200 − 20 = 180 After the demand shifts, the new demand function becomes: qD₂ = 150 − p At p = 20, qD₂ = 150 − 20 = 130 Thus, the reduction in market demand is: 180 − 130 = 50 units If each firm supplies: qf = 10 units then the number of firms that must exit is: 50 ÷ 10 = 5 firms Therefore, Option C is correct.

For simultaneous shifts: Demand Right & Supply Right both increase equilibrium quantity. Therefore, 1 → a. Demand Left & Supply Left both reduce equilibrium quantity. Therefore, 2 → b. Demand Left & Supply Right both reduce equilibrium price. Therefore, 3 → c. Demand Right & Supply Left both increase equilibrium price. Therefore, 4 → d. Thus, the correct matching is: 1 → a 2 → b 3 → c 4 → d Hence, Option C is correct.

Evaluate each statement: Statement I: Demand shifts left while supply shifts right. Both forces reduce equilibrium price. - Correct. Statement II: Demand shifts right while supply shifts left. Both forces increase equilibrium price. - Correct. Statement III: Quantity is not always zero. It depends on the relative magnitude of the demand and supply shifts and may increase, decrease, or remain unchanged. - Incorrect. Thus, Statements I and II are correct. Hence, Option A is correct.

When demand shifts leftward, equilibrium price decreases. Similarly, when supply shifts rightward, equilibrium price also decreases. Therefore, the equilibrium price definitely decreases. However, the two shifts have opposite effects on equilibrium quantity: A leftward demand shift decreases quantity. A rightward supply shift increases quantity. Thus, the final effect on quantity depends on which shift is larger, making it ambiguous. Therefore, the blanks are: Decrease Ambiguous Hence, Option D is correct.

When both the demand curve and the supply curve shift leftward simultaneously, each shift independently reduces the equilibrium quantity. A leftward demand shift lowers the quantity demanded at every price, reducing equilibrium quantity. A leftward supply shift lowers the quantity supplied at every price, also reducing equilibrium quantity. Since both shifts move the equilibrium quantity in the same direction, the effect is unambiguous. Although the effect on equilibrium price depends on the relative magnitudes of the two shifts, the equilibrium quantity definitely decreases. Therefore, Option B is correct.

The sequence begins with an increase in the cost of an input, which raises firms' production costs. As a result: Step 3: Cost of an input increases. Step 1: Market supply curve shifts leftward because firms supply less at every price. Step 4: At the original equilibrium price, quantity demanded exceeds quantity supplied, creating excess demand. Step 2: The shortage pushes the equilibrium price upward until a new market equilibrium is reached. Thus, the correct order is: 3 → 1 → 4 → 2 Hence, Option B is correct.

In the fixed firms case, the number of firms remains unchanged in the short run. Therefore, when demand increases, the market adjusts mainly through a rise in equilibrium price, resulting in only a limited increase in equilibrium quantity. In contrast, under free entry and exit, higher demand attracts new firms into the industry. As firms enter, market supply expands, allowing a much larger increase in equilibrium quantity while the long-run equilibrium price remains equal to Minimum Average Cost (Min AC). Thus: Assertion (A) is true. Reason (R) is true. Reason (R) correctly explains why the increase in quantity is smaller in the fixed-firms case. Therefore, Option C is correct.

According to the passage and NCERT, under free entry and exit, the long-run equilibrium price is always equal to the minimum average cost of the firms. When demand shifts leftward, some firms exit the industry because market demand decreases. The reduction in the number of firms shifts market supply leftward until equilibrium is restored. Although market quantity decreases and fewer firms remain in the market, the equilibrium price continues to equal the minimum average cost. Therefore, Option B is correct.

The passage states that under free entry and exit, the equilibrium price always remains equal to the minimum average cost. If demand increases: New firms enter the industry. Market supply expands. Equilibrium quantity increases. If demand decreases: Some firms exit the industry. Market supply contracts. Equilibrium quantity decreases. Thus, a demand shift changes the equilibrium quantity and the number of firms, while the equilibrium price remains unchanged. Therefore, Option D is correct.