Samacheer Kalvi Class 11 Economics Solutions Chapter 4 Cost and Revenue Analysis

Part - A

Multiple Choice Questions:

 

Question 1. Cost refers to _______________.
(a) Price
(b) Value
(c) Fixed cost
(d) Cost of production
Answer: (d) Cost of production
In simple words: Cost means all the money spent to make something. It includes everything from buying materials to paying workers.

🎯 Exam Tip: Remember that "cost" in economics refers to all expenses involved in making goods or services, not just the selling price or value.

 

Question 2. Cost functions are also known _______________ function.
(a) production
(b) investment
(c) demand
(d) consumption
Answer: (a) production
In simple words: Cost functions are basically rules that show how the cost changes when you make more or less of a product. They are directly linked to how things are produced.

🎯 Exam Tip: Understand that a cost function mathematically represents the relationship between production output and the total cost incurred, making it a key concept in microeconomics.

 

Question 3. Money cost is also known as _______________ cost.
(a) Explicit
(b) Implicit
(c) Social
(d) Real
Answer: (a) Explicit
In simple words: Money cost is another name for explicit cost because it refers to the actual cash payments made for things like wages or rent. These are costs that are clearly visible and recorded.

🎯 Exam Tip: Distinguishing between explicit and implicit costs is crucial; explicit costs are direct monetary payments, while implicit costs are opportunity costs of using self-owned resources.

 

Question 4. Explicit cost plus implicit cost denote _______________ cost.
(a) social
(b) economic
(c) money
(d) fixed
Answer: (b) economic
In simple words: When you add up both the direct money payments (explicit costs) and the value of using your own resources (implicit costs), you get the full economic cost. This shows the true total cost of production.

🎯 Exam Tip: Economic cost is a broader concept than accounting cost, as it includes both explicit (out-of-pocket) and implicit (opportunity) costs, providing a more complete picture for decision-making.

 

Question 5. Explicit costs are termed as _______________.
(a) Out of pocket expenses
(b) Real cost
(c) Social cost
(d) Sunk cost
Answer: (a) Out of pocket expenses
In simple words: Explicit costs are often called "out of pocket expenses" because they are direct payments made with money. They are easy to see and record in financial books.

🎯 Exam Tip: Remember that explicit costs are actual monetary payments for inputs, easily identifiable and recorded in accounting statements.

 

Question 6. The costs of self-owned resources are termed as _______________ cost.
(a) real
(b) explicit
(c) money
(d) implicit
Answer: (d) implicit
In simple words: When a business uses its own things, like its own building or time, without making a direct payment, the value of using these things is called an implicit cost. It's a cost you don't pay with cash, but it's still a real cost.

🎯 Exam Tip: Implicit costs represent the opportunity cost of using resources the firm already owns, and are crucial for economic decision-making, even though they don't involve a cash outflow.

 

Question 7. The cost that remains constant at all levels of output is _______________ cost.
(a) Fixed
(b) Variable
(c) Real
(d) Social
Answer: (a) Fixed
In simple words: A fixed cost is like your rent; you have to pay it no matter how much you produce. It stays the same even if you make zero or a lot of products.

🎯 Exam Tip: Fixed costs do not change with the quantity of output produced in the short run and are important for calculating total cost and average fixed cost.

 

Question 8. Identify the formula of estimating average variable _______________ cost.
(a) TC/Q
(b) TVC/Q
(c) TFC/Q
(d) TAC/Q
Answer: (b) TVC/Q
In simple words: To find the average variable cost, you simply divide the total variable cost by the total quantity produced. This tells you the variable cost for each unit.

🎯 Exam Tip: Remember that Average Variable Cost (AVC) is the total variable cost (TVC) divided by the quantity (Q), representing the variable cost per unit of output.

 

Question 9. The cost incurred by producing one more unit of output is _______________ cost.
(a) Variable
(b) Fixed
(c) Marginal
(d) Total
Answer: (c) Marginal
In simple words: Marginal cost is the extra cost a business pays when it makes just one more item. It helps decide if making more items is worth it.

🎯 Exam Tip: Marginal cost is crucial for understanding how costs change with small adjustments in production levels and for making optimal output decisions.

 

Question 10. The cost that varies with the level of output is termed as _______________ cost.
(a) money
(b) variable cost
(d) fixed cost
Answer: (b) variable cost
In simple words: A variable cost changes as you make more or fewer goods. For example, the cost of raw materials goes up if you make more products.

🎯 Exam Tip: Variable costs are directly tied to the level of production, increasing as output rises and decreasing as output falls.

 

Question 11. Wage is an example of _______________ cost of the production.
(a) Fixed
(b) Variable
(c) Marginal
(d) Opportunity
Answer: (b) Variable
In simple words: Wages paid to workers who make products are variable costs because if you produce more, you might need more workers or more hours, increasing the total wage payment. If production stops, these wages might also stop.

🎯 Exam Tip: Identify whether a cost changes with output levels; if it does, it's a variable cost, like direct labor wages, raw materials, or power used in production.

 

Question 12. The cost per unit of output is denoted by _______________ cost.
(a) average
(b) marginal
(c) variable
(d) total
Answer: (a) average
In simple words: The average cost tells you how much it costs to make one item on average. You find it by dividing the total cost by the number of items made.

🎯 Exam Tip: Average cost, often denoted as AC or ATC, is a fundamental measure for understanding a firm's efficiency and profitability at different output levels.

 

Question 13. Identify the formula for estimating average cost.
(a) AVC/Q
(b) TC/Q
(c) TVC/Q
(d) AFC/Q
Answer: (b) TC/Q
In simple words: Average cost is calculated by taking the total cost of production and dividing it by the total quantity of goods produced. This gives you the cost for each unit on average.

🎯 Exam Tip: Remember that Average Cost (AC or ATC) is always Total Cost (TC) divided by Quantity (Q), which helps in understanding per-unit expenses.

 

Question 14. Find total cost where TFC = 100 and TVC = 125.
(a) 125
(b) 175
(c) 225
(d) 325
Answer: (c) 225
In simple words: Total cost is found by adding the total fixed cost (TFC) and the total variable cost (TVC) together. So, 100 plus 125 equals 225.

🎯 Exam Tip: Always remember the basic cost equation: Total Cost (TC) = Total Fixed Cost (TFC) + Total Variable Cost (TVC).

 

Question 15. Long-run average cost curve is also called a _______________ curve.
(a) Demand
(b) Planning
(c) Production
(d) Sales
Answer: (b) Planning
In simple words: The long-run average cost curve is called a "planning curve" because firms use it to decide the best size for their operations in the future. It helps businesses plan for a longer time by choosing the most efficient plant size.

🎯 Exam Tip: The Long-run Average Cost (LAC) curve is an envelope of all short-run average cost curves, used for strategic planning of optimal plant size.

 

Question 16. Revenue received from the sale of products is known as _______________ revenue.
(a) profit
(b) total revenue
(c) average
(d) marginal
Answer: (b) total revenue
In simple words: The total money a company gets from selling all its goods or services is called total revenue. It is the full amount of sales income before any costs are taken out.

🎯 Exam Tip: Total revenue is simply price multiplied by quantity sold, representing the gross income from sales.

 

Question 17. Revenue received from the sale of an additional unit is termed as _______________ revenue.
(a) Profit
(b) Average
(c) Marginal
(d) Total
Answer: (c) Marginal
In simple words: Marginal revenue is the extra money a business earns when it sells one more item. It shows how much income increases with each additional unit sold.

🎯 Exam Tip: Marginal revenue is critical for firms to determine the profit-maximizing level of output by comparing it with marginal cost.

 

Question 18. Marginal revenue is the addition made to the _______________.
(a) total sales
(b) total revenue
(c) total production
(d) total cost
Answer: (b) total revenue
In simple words: Marginal revenue adds to the total money a company earns. When you sell one more item, the extra money you get is added to your total earnings.

🎯 Exam Tip: Clearly distinguish between total sales (quantity sold) and total revenue (money earned from sales); marginal revenue directly relates to the latter.

 

Question 19. When price remains constant, AR will be _______________ MR.
(a) Equal to
(b) Greater than
(c) Less than
(d) Not related to
Answer: (a) Equal to
In simple words: When a company sells all its products at the same price, the average money earned per item (AR) is the same as the extra money earned from selling one more item (MR). This is common in perfect competition.

🎯 Exam Tip: In perfectly competitive markets, price is constant, leading to AR = MR = Price, which is a key characteristic for firm analysis.

 

Question 20. A bookseller sold 40 books with a price of Rs.10 each. The total revenue of the seller is Rs. _______________.
(a) 100
(b) 200
(c) 300
(d) 400
Answer: (d) 400
In simple words: To find the total money earned, you multiply the number of books sold by the price of each book. So, 40 books times Rs. 10 each gives a total of Rs. 400.

🎯 Exam Tip: Always calculate total revenue by multiplying the quantity sold by the price per unit.

 

Part - B

Answer The Following Questions In One Or Two Sentences.

 

Question 21. Define cost?
Answer: Cost refers to the total expenses a business pays to produce a good or service. This includes all the money spent on things like raw materials, wages, rent, and other necessary inputs. The cost is a key factor in deciding the final price of a product.
In simple words: Cost is all the money spent to make something. It includes all the payments for things needed in production.

🎯 Exam Tip: When defining cost, ensure you mention it covers all expenses for production, highlighting its comprehensive nature beyond just raw materials.

 

Question 22. Define cost function.
Answer: A cost function shows how the total cost of production is related to the amount of goods produced. It is expressed mathematically as \( C = f(Q) \), where \( C \) is the total cost and \( Q \) is the quantity of output. This function helps businesses understand how their costs change with different production levels.
In simple words: A cost function shows the link between how much you make and how much it costs. It uses a formula to connect cost to the number of items produced.

🎯 Exam Tip: Clearly state that a cost function is a mathematical relationship (C = f(Q)) explaining how total cost depends on the level of output.

 

Question 23. What do you mean by fixed cost?
Answer: Fixed costs are expenses that do not change, no matter how much a business produces. These costs remain constant whether the output is high, low, or even zero. Examples include rent for a factory or the salary of permanent staff. Fixed costs are paid even when no goods are being made.
In simple words: Fixed costs are payments that stay the same. You pay them even if you don't make anything.

🎯 Exam Tip: When explaining fixed cost, emphasize its independence from the level of output in the short run, providing common examples like rent or insurance.

 

Question 24. Define Revenue.
Answer: Revenue is the total amount of money a business gets from selling its goods or services to customers. It represents the income generated from sales activities before any expenses are deducted. For a producer, revenue is the cash received in exchange for sold products. It is crucial for a firm's financial health.
In simple words: Revenue is the total money a company gets from selling its products. It's the income from sales.

🎯 Exam Tip: Define revenue as the total income from sales (Price × Quantity) and clarify that it's gross income before costs.

 

Question 25. Explicit Cost – Define?
Answer: Explicit costs are the direct payments a business makes to outsiders for using their resources. These are "out-of-pocket" expenses that involve a clear transfer of money, such as wages paid to employees, rent for a building, or money spent on raw materials. Explicit costs are recorded in the company's accounting books.
In simple words: Explicit costs are direct cash payments a business makes to others. They are clear expenses like wages or rent.

🎯 Exam Tip: Highlight that explicit costs are actual, tangible cash outlays, easily recorded and verifiable in financial statements.

 

Question 26. Give the definition for 'Real Cost'.
Answer: According to economist Adam Smith, 'real cost' refers to the pains and personal sacrifices involved in producing goods. It includes the effort, tiredness, and discomfort that workers face, as well as the sacrifices of those who own capital. This concept focuses on the human element behind production.
In simple words: Real cost means the hard work and sacrifices people make to produce things. It includes pains and efforts, like those mentioned by Adam Smith.

🎯 Exam Tip: When defining real cost, mention Adam Smith and emphasize the non-monetary aspects, such as pains and sacrifices, associated with production.

 

Question 27. What is meant by Sunk Cost?
Answer: A sunk cost is an expense that has already been paid and cannot be recovered. Once a sunk cost is incurred, it cannot be changed or retrieved, regardless of future decisions. For example, money spent on a unique machine that cannot be sold or used for another purpose is a sunk cost. It should not influence future business choices.
In simple words: A sunk cost is money already spent that you cannot get back. It is a past payment that does not affect future choices.

🎯 Exam Tip: The key characteristic of a sunk cost is that it is irreversible and should not be considered in future decision-making.

 

Part - C

Answer The Following Questions In One Paragraph.

 

Question 28. Distinguish between Fixed Cost and Variable Cost?
Answer:

Understanding the difference between fixed and variable costs is important for businesses to manage their expenses and plan for future production levels. For example, knowing which costs are fixed helps in setting a break-even point.
In simple words: Fixed costs stay the same no matter how much you produce, like rent. Variable costs change with how much you produce, like raw materials. Fixed costs are overheads, while variable costs are direct costs.

🎯 Exam Tip: Clearly define each cost type and provide distinct examples for both fixed and variable costs to illustrate their differing behaviors with output changes.

 

Question 29. State the difference between money cost and real cost?
Answer:

While money cost is easily quantifiable and recorded in accounting books, real cost offers a deeper, more philosophical understanding of the true burden of production. Both are important in economic analysis.
In simple words: Money cost is the actual cash spent to make things. Real cost is the effort and sacrifice people make, like hard work. Money cost is easy to count, but real cost is about human struggle.

🎯 Exam Tip: Clearly differentiate that money cost is monetary and measurable, while real cost is a non-monetary concept reflecting human effort and sacrifice.

 

Question 30. Distinguish between Explicit Cost and Implicit Cost?
Answer:

Businesses need to consider both explicit and implicit costs to get a complete picture of their economic profitability, as implicit costs represent missed opportunities for the owner's resources. For example, the explicit cost is the salary you pay an employee, while an implicit cost is the income you could have earned if you rented out your own office space instead of using it yourself.
In simple words: Explicit costs are money paid to outsiders for things like rent or wages. Implicit costs are the value of using your own things, like your own building, which you don't pay cash for. Explicit costs are easy to see, implicit costs are hidden.

🎯 Exam Tip: Emphasize that explicit costs are monetary and recorded (accounting costs), while implicit costs are non-monetary opportunity costs of owned resources (economic costs).

 

Question 31. Define opportunity cost and provide an example.
Answer:
1. Opportunity cost is the value of the next best choice that was not taken when a decision was made. It represents what you give up when you choose one option over another. This cost helps in understanding trade-offs.
2. For example, imagine a farmer who can grow either paddy or sugarcane on his land.
3. If the farmer decides to grow paddy, the opportunity cost of growing paddy is the amount of sugarcane he could have grown instead.
4. Opportunity Cost is also known as "Alternative Cost" or "Transfer cost". It is a fundamental concept in economics.
In simple words: Opportunity cost is what you miss out on when you pick one thing over another. It's the value of your second-best choice. For a farmer, if he grows rice, his opportunity cost is the sugarcane he could have grown instead.

🎯 Exam Tip: Clearly define opportunity cost as the value of the *next best* alternative foregone, and use a simple, concrete example to illustrate the concept effectively.

 

Question 32. State the relationship between AC and MC?
Answer: There is a clear relationship between the Average Cost (AC) and Marginal Cost (MC) curves, as shown in the diagram below.

1. When AC (Average Cost) is falling, MC (Marginal Cost) is below AC. This means making one more unit costs less than the average, pulling the average down.
2. When AC is at its lowest point, MC is equal to AC. At this point, the extra cost of one more unit is exactly the same as the average cost.
3. When AC starts to rise, MC is above AC. This indicates that making one more unit costs more than the average, pushing the average up.
4. The MC curve always cuts the AC curve at its lowest point. This is a fundamental rule in cost theory, illustrating efficiency changes.
These relationships are essential for firms to understand their production efficiency and make pricing decisions.
In simple words: When the average cost goes down, the marginal cost is lower than it. When the average cost is lowest, the marginal cost is equal to it. When the average cost goes up, the marginal cost is higher than it. The marginal cost line always crosses the average cost line at its lowest point.

🎯 Exam Tip: Focus on explaining the three key stages of the AC-MC relationship: when AC is falling (MC < AC), when AC is at its minimum (MC = AC), and when AC is rising (MC > AC).

 

Question 33. Write a short note on Marginal Revenue.
Answer:
1. Marginal Revenue (MR) is the extra money a business gets from selling one more unit of its product. It is the change in total revenue when output increases by one unit.
2. MR can be found by dividing the change in total revenue (\( \Delta TR \)) by the change in quantity sold (\( \Delta Q \)).
3. So, \( MR = \frac{\Delta TR}{\Delta Q} \), where \( MR \) is Marginal Revenue, \( \Delta TR \) is the change in Total Revenue, and \( \Delta Q \) is the change in total quantity.
4. Another way to calculate \( MR \) is:
\( MR = TR_n - TR_{n-1} \), (or) \( TR_{n+1} - TR_n \).
Here, \( MR \) means Marginal Revenue, \( TR_n \) is the total revenue for the \( n^{th} \) item, \( TR_{n-1} \) is the Total Revenue for the \( (n-1)^{th} \) item, and \( TR_{n+1} \) is the Total Revenue for the \( (n+1)^{th} \) item.
If total revenue \( TR = PQ \) (Price x Quantity), then the marginal revenue is given by the derivative of total revenue with respect to quantity: \( MR = \frac{dTR}{dQ} = P \), which is also equal to Average Revenue (AR) when price is constant. Marginal revenue is a key concept for firms aiming to maximize profit.
In simple words: Marginal Revenue is the extra money you get from selling just one more item. You calculate it by seeing how much your total sales money changes when you sell one more unit. If the price doesn't change, the marginal revenue is just the price of that extra item.

🎯 Exam Tip: Define marginal revenue clearly as the change in total revenue from selling one additional unit, and include its formula \( MR = \frac{\Delta TR}{\Delta Q} \).

 

Question 34. Discuss the Long run cost curves with a suitable diagram?
Answer:
1. In the long run, a business can change all its factors of production, meaning all costs become variable. The firm can expand or reduce its existing size. In the long run, there are no fixed inputs or fixed costs. This gives businesses a lot of flexibility.
2. The Long-Run Average Cost (LAC) curve is shown in the diagram below.
3. Long-run average cost (LAC) is found by dividing the long-run total costs (LTC) by the level of output (Q). This shows the lowest cost per unit for any output level when all inputs can be changed.
The formula is: \( LAC = \frac{LTC}{Q} \), where \( LAC \) is Long-Run Average Cost, \( LTC \) is Long-run Total Cost, and \( Q \) is the quantity of output.

The LAC curve is formed by the bottom parts of many short-run average cost curves. It shows the lowest possible cost to produce any level of output when the firm can choose the best plant size. The LAC curve is often called a 'Plant Curve', 'Boat Shape Curve', or 'Planning Curve' because it helps firms plan their long-term production.
In simple words: In the long run, companies can change everything about their production. The Long-Run Average Cost (LAC) curve shows the lowest cost to make things when a company can pick the best factory size. It looks like a boat and helps plan for the future.

🎯 Exam Tip: Explain that in the long run, all costs are variable, and the LAC curve is derived by "enveloping" the series of short-run average cost curves, representing optimal plant choices.

Part - D

Answer the following questions in about a page.

 

Question 35. If total cost = 10 + \( Q^3 \), find out AC, AVC, TFC, AFC when Q = 5?
Answer:
Given: Total Cost \( TC = 10 + Q^3 \)
Quantity \( Q = 5 \)

First, we find Total Cost (TC) when \( Q = 5 \):
\( TC = 10 + 5^3 = 10 + 125 = 135 \)

Next, we find Average Cost (AC):
\( AC = \frac{TC}{Q} = \frac{135}{5} = 27 \)

For Total Fixed Cost (TFC), when output \( Q = 0 \), total cost is \( TC = 10 + 0^3 = 10 \). Fixed costs do not change with output.
So, \( TFC = 10 \)

Then, we find Total Variable Cost (TVC):
\( TVC = TC - TFC = (10 + Q^3) - 10 = Q^3 \)
For \( Q = 5 \), \( TVC = 5^3 = 125 \)

After that, we calculate Average Variable Cost (AVC):
\( AVC = \frac{TVC}{Q} = \frac{Q^3}{Q} = Q^2 \)
For \( Q = 5 \), \( AVC = 5^2 = 25 \)

Finally, we calculate Average Fixed Cost (AFC):
\( AFC = \frac{TFC}{Q} = \frac{10}{Q} \)
For \( Q = 5 \), \( AFC = \frac{10}{5} = 2 \)
In simple words: We calculate total cost by putting the quantity into the given formula. Then, we find average cost by dividing total cost by quantity. Fixed cost is the part of total cost when nothing is produced. Variable cost changes with how much is made. Average variable cost and average fixed cost divide these by the quantity.

🎯 Exam Tip: Remember that TFC remains constant regardless of output, and TVC is TC minus TFC. Use these relationships to find all the different cost measures.

 

Question 36. Discuss the short-run cost curves with a suitable diagram?
Answer:
In the short run, some factors of production are fixed, while others are variable. This leads to different types of costs and their unique curves.

Short-run Cost Curves:
Total Fixed Cost (TFC):
Total Fixed Cost (TFC) refers to all payments made for the fixed factors of production. These costs do not change as the output level changes. For example, rent for a factory or machinery cost remains the same whether a firm produces one unit or a hundred units. TFC is always shown as a horizontal line on a graph, parallel to the X-axis.
For example, if the total fixed cost is Rs 1000, it stays Rs 1000 for all levels of output.

Total Variable Cost (TVC):
Total Variable Cost (TVC) includes all payments for variable factors of production, which change with the level of output. For instance, the cost of raw materials or temporary worker wages increases as more units are produced. When output is zero, TVC is also zero. As output rises, TVC typically increases, often first at a decreasing rate, then at an increasing rate.

Total Cost (TC):
Total Cost is the sum of Total Fixed Cost and Total Variable Cost. It represents all expenses made in production. The TC curve starts at the TFC level on the Y-axis (when output is zero) and then rises, running parallel to the TVC curve.
\( TC = TFC + TVC \)
For example, if TFC is Rs 1000 and TVC is Rs 200, then TC is Rs 1200.

Average Fixed Cost (AFC):
Average Fixed Cost (AFC) is the fixed cost per unit of output. It is calculated by dividing total fixed cost (TFC) by the quantity of output (Q). As output increases, AFC continuously decreases because the same fixed cost is spread over more units. The AFC curve is always downward sloping and never touches the axes, forming a rectangular hyperbola.
\( AFC = \frac{TFC}{Q} \)
For example, if TFC is Rs 1000 and Q is 10, then AFC is Rs 100.

Average Variable Cost (AVC):
Average Variable Cost (AVC) is the variable cost per unit of output. It is calculated by dividing total variable cost (TVC) by the quantity of output (Q). The AVC curve is typically U-shaped. It first falls as output increases due to economies of scale (better use of resources), reaches a minimum point, and then rises as output continues to increase due to diseconomies of scale (overuse of resources).
\( AVC = \frac{TVC}{Q} \)
For example, if TVC is Rs 300 and Q is 2, then AVC is Rs 150.

Average Total Cost (ATC) or Average Cost (AC):
Average Total Cost (ATC) is the total cost per unit of output. It is found by dividing total cost (TC) by quantity (Q), or by adding Average Fixed Cost (AFC) and Average Variable Cost (AVC). The ATC curve is also U-shaped, generally falling initially, then rising. It reflects the combined behavior of AFC (which always falls) and AVC (which first falls then rises). The AC curve is the sum of AFC and AVC curves.
\( ATC = \frac{TC}{Q} \) or \( ATC = AFC + AVC \)

Marginal Cost (MC):
Marginal Cost (MC) is the extra cost of producing one more unit of output. It is found by dividing the change in total cost (ΔTC) by the change in quantity (ΔQ). The MC curve is also typically U-shaped and intersects both the AVC and ATC curves at their lowest points. It helps a firm decide if producing an additional unit is profitable.
\( MC = \frac{\Delta TC}{\Delta Q} \)
For example, if a firm produces 4 units at a total cost of Rs 1600, and 5 units at a total cost of Rs 1900, the marginal cost of the 5th unit is Rs \( 1900 - 1600 = 300 \).

In simple words: Short-run costs include fixed costs (which don't change), variable costs (which do change with output), and total costs (the sum of both). Per-unit costs like average fixed, average variable, and average total costs are also important. Marginal cost is the extra cost for one more item. Each cost type has its own curve shape that shows how it behaves as production increases.

🎯 Exam Tip: When drawing cost curves, always clearly label both axes (Output/Quantity on X, Cost on Y) and each curve. Remember the U-shape for AVC, AC, and MC, and the horizontal line for TFC.

 

Question 37. Bring out the relationship between AR and MR curves under various price conditions?
Answer:
The relationship between Average Revenue (AR) and Marginal Revenue (MR) curves changes based on whether the price is constant or declining. Understanding these relationships is crucial for firms to make production and pricing decisions.

Relationship between AR and MR Curves:
When a firm can sell more units only by lowering the price, both AR and MR will fall, and MR will always fall faster than AR. However, if a firm can sell additional units at a constant price, then both AR and MR will remain constant and equal.

Constant AR and MR (at Fixed Price):
In perfect competition, the price of a product is fixed and uniform. This means that each additional unit sold brings the same revenue as the previous one. Therefore, Marginal Revenue (MR) remains constant and is equal to the Average Revenue (AR). On a graph, both the AR and MR curves will be a single horizontal straight line, parallel to the X-axis.

Declining AR and MR (at Declining Price):
When a firm operates under imperfect competition (like monopoly or monopolistic competition), it can sell more units only by reducing the price. In this case, both Average Revenue (AR) and Marginal Revenue (MR) will fall as output increases. The MR curve will always be below the AR curve and will fall at a steeper rate than the AR curve. This means that each additional unit sold adds less to total revenue than the average revenue per unit.

In simple words: How much money a company makes per item (Average Revenue) and how much extra money it makes from selling one more item (Marginal Revenue) depends on whether the price stays the same or goes down. If the price is always the same, AR and MR are equal lines. If the price goes down to sell more, then AR and MR both fall, but MR falls faster.

🎯 Exam Tip: Clearly distinguish between fixed and declining price conditions. Remember that under fixed prices, AR=MR, but under declining prices, MR < AR and falls more sharply.

 

Additional Important Questions and Answers

Part - A

 

Question 1. Real cost is ______
(a) Pain and sacrifice
(b) Subjective
(c) Efforts and sacrifice
(d) All of the options
Answer: (d) All of the options
In simple words: Real cost includes the feelings of effort and giving up something important. These feelings are different for everyone and involve what people sacrifice to produce goods.

🎯 Exam Tip: Remember that "real cost" goes beyond just money; it includes the human effort and sacrifices involved in production.

 

Question 2. Social Cost is those costs ______
(a) Not borne by the firms
(b) Incurred by the society
(c) Health hazards
(d) All of the options
Answer: (d) All of the options
In simple words: Social costs are the total costs that society faces because of producing something. This includes costs not directly paid by companies, like pollution or health problems for people living nearby.

🎯 Exam Tip: When thinking about social costs, consider the wider impact on the community and environment, not just the company's direct expenses.

 

Question 3. Economic profit is ______
(a) TR-TC
(b) TC-TR
(c) AC-MC
(d) None of the options
Answer: (a) TR-TC
In simple words: Economic profit is what's left after you subtract all the costs (both obvious and hidden ones) from the total money a business makes. It's different from accounting profit because it also considers opportunity costs.

🎯 Exam Tip: Always remember that economic profit considers both explicit and implicit costs, making it a more complete measure than accounting profit.

 

Question 4. Profit is the difference between Total Revenue and ______
(a) Total Cost
(b) Total Variable
(c) Total Fixed Cost
(d) Total Marginal Cost
Answer: (a) Total Cost
In simple words: Profit is the money a business earns after it pays for all its expenses. You find it by taking the total money brought in (total revenue) and subtracting all the money spent (total cost).

🎯 Exam Tip: The fundamental formula for profit is Total Revenue minus Total Cost; this forms the basis for all profit calculations.

 

Question 5. How can you calculate the average cost?
(a) TVC + TFC
(b) TC – AC
(c) TC / Q
(d) AC / Q
Answer: (c) TC / Q
In simple words: To find the average cost, you take the total money spent on making products and divide it by the number of products made. This tells you the cost for each item on average.

🎯 Exam Tip: Average cost is always calculated by dividing a total cost (like TC, TVC, or TFC) by the quantity of output (Q).

 

Question 6. What is an envelope curve?
(a) Planning curve
(b) Long-run cost curve
(c) U – shape curve
(d) V – shape curve
Answer: (a) Planning curve
In simple words: An envelope curve, like the long-run average cost curve, helps a company choose the best size for its factory or production setup. It shows the lowest possible average cost for producing any amount of goods over a long time.

🎯 Exam Tip: The long-run average cost (LAC) curve is often called an "envelope curve" because it "envelopes" or touches the short-run average cost (SAC) curves at their most efficient points.

 

Question 7. Social cost is ______
(a) Not borne by the firm
(b) Borne by the society
(c) Air pollution by the firm
(d) All of the options
Answer: (d) All of the options
In simple words: Social cost is the total burden on society from making something. It includes problems like pollution, which the company doesn't directly pay for, but society suffers from.

🎯 Exam Tip: Social costs often include negative external effects like environmental damage or health impacts that affect the public, not just the producer.

 

Question 8. Implicit cost is also known as ______
(a) Explicit Cost
(b) Economic Cost
(c) Social Cost
(d) Imputed Cost
Answer: (d) Imputed Cost
In simple words: Implicit cost is the hidden cost of using your own resources for your business. It's like the money you miss out on by not using those resources in their best alternative way.

🎯 Exam Tip: Implicit costs are also called "opportunity costs" or "imputed costs" because they represent the value of what you give up by using your own resources in one way rather than another.

 

Question 9. Long-run average cost curve can also be called as ______
(a) Planning curve
(b) Envelope curve
(c) Boat-shaped curve
(d) All of the options
Answer: (d) All of the options
In simple words: The long-run average cost curve is known by many names because it helps businesses plan their production and shows the best way to make goods in the long term. It covers many short-term production choices like an envelope.

🎯 Exam Tip: The long-run average cost (LAC) curve has several descriptive names (Planning, Envelope, Boat-shaped) because it helps firms plan their long-term scale of operations and represents the lower boundary of all short-run average cost curves.

 

Question 10. How will you calculate AR?
(b) \( AR = \frac{TVR}{Q} \)
Answer: (b) AR = \frac{TVR}{Q}
In simple words: Average Revenue is found by dividing the total income a company gets from selling its products by the number of units it sells. This helps to see how much revenue each item brings in on average.

🎯 Exam Tip: While AR is typically Total Revenue (TR) divided by Quantity (Q), it is important to understand the specific formula or terms used in a given context.

Part - B

Answer the following questions in one or two sentences.

 

Question 1. What does money cost?
Answer: Money cost refers to the cost of production that is expressed in terms of money. It represents the total money spent by a firm to produce a good.
In simple words: Money cost is how much money a business spends to make something.

🎯 Exam Tip: Remember to specify "money terms" when defining money cost to distinguish it from real cost.

 

Question 2. Define Floating Cost?
Answer: Floating cost includes all expenses directly linked to business activities but not for creating assets. These costs do not include buying raw materials, which are current assets. Examples include wages, transport fees, power charges, and administrative expenses. Floating costs are essential for a firm's day-to-day operations.
In simple words: Floating costs are everyday expenses like wages and transport that a business needs to run, but not for buying big assets.

🎯 Exam Tip: When defining floating costs, highlight that they are for ongoing operations and do not create assets, differentiating them from capital expenditures.

 

Question 3. What is the social cost?
Answer: Social cost refers to the overall expense borne by society due to the making of a product. Alfred Marshall defined it as the efforts and sacrifices made by different parts of society when a product is created. For example, large companies can cause air and water pollution, which creates a cost for society.
In simple words: Social cost is the total price society pays when a product is made, including things like pollution.

🎯 Exam Tip: To score well, define social cost broadly and include a clear example like pollution, as this illustrates the external costs to society.

 

Part - C

Answer the following questions in one paragraph.

 

Question 1. Bring out the distinction between short-run and long Run?
Answer: