Q.Which of the following is a basic feature of a market under perfect competition?
Concept understanding — Perfect Competition
Perfect competition is one of those ideas in economics that sounds technical but actually describes something you see every day — a market where no single seller has any real power, and the price is just… the price.
The everyday intuition
Think of a vegetable market in your town. There are dozens of vendors selling tomatoes. All the tomatoes are more or less the same. You can walk from one stall to another and buy from anyone. If one vendor tries to charge ₹10 more per kilo than the others, you simply walk to the next stall. That vendor loses customers instantly. So every vendor ends up charging the same price — the market price. No one decides it; it just emerges from everyone buying and selling.
That’s the core feel of perfect competition: price-takers, not price-makers.
The precise meaning
In economics, a market is called perfectly competitive when it satisfies five conditions. NCERT Class-12 (Introductory Microeconomics, Chapter 4) lists them clearly:
- Large number of buyers and sellers — so many that no single buyer or seller can influence the market price by their own action.
- Homogeneous product — the good sold by every firm is identical. No branding, no quality difference. A buyer has no reason to prefer one seller over another.
- Perfect information — every buyer and seller knows the price prevailing in the market. No one is tricked into paying more.
- Free entry and exit — any new firm can start producing and selling, and any existing firm can shut down and leave, without legal or cost barriers.
- No transaction costs — buyers and sellers can trade directly without extra expenses like transport or middlemen.
When all five hold, the market is perfectly competitive. In reality, no market is perfectly competitive — but agricultural markets, stock markets for widely traded shares, and online commodity markets come close.
Why it matters
Perfect competition is the benchmark — the ideal against which all real markets are compared. It tells us what happens when competition is at its maximum.
The key result is that in the long run, firms earn zero economic profit. That doesn’t mean they make no money — it means they earn just enough to cover all costs, including a normal return on their investment. If profits were positive, new firms would enter, supply would increase, price would fall, and profits would be squeezed back to zero. If losses occurred, firms would exit, supply would fall, price would rise, and losses would disappear.
This leads to two important outcomes:
- Productive efficiency: Firms produce at the lowest possible cost per unit (the minimum of the average cost curve).
- Allocative efficiency: The price equals the marginal cost of production — society gets exactly the quantity it values.
In a perfectly competitive market, the demand curve facing a single firm is a horizontal line at the market price. The firm can sell any quantity at that price, but nothing above it. This is why the firm is a price taker.
The revenue and profit picture (with a formula)
For a firm in perfect competition, the market price P is given. The firm’s total revenue is:
TR=P×Q
where Q is the quantity the firm sells. Since P is constant, each additional unit sold adds exactly P to revenue. So the marginal revenue MR is also P:
MR=P
The firm maximises profit by producing the quantity where MR=MC, where MC is marginal cost. Since MR=P, the profit-maximising rule becomes:
P=MC
This is the famous condition for a competitive firm’s equilibrium.
P=MC
- P = market price (constant for the firm)
- MC = marginal cost (the cost of producing one more unit)
The firm’s profit is:
π=TR−TC=(P×Q)−(ATC×Q)=(P−ATC)×Q
where ATC is average total cost. If P>ATC, the firm makes supernormal profit. If P=ATC, profit is zero (normal profit). If P<ATC, the firm incurs a loss.
A diagram in words
Imagine a graph with quantity on the horizontal axis and price/cost on the vertical axis. Draw a U-shaped average total cost curve and a U-shaped average variable cost curve below it. The marginal cost curve cuts through the minimum points of both.
Now draw a horizontal line at the market price P. This is the firm’s demand curve and also its marginal revenue curve. Where this horizontal line intersects the marginal cost curve — that’s the profit-maximising quantity Q∗.
If the horizontal line lies above the average total cost curve at Q∗, the firm makes profit (the vertical gap times quantity). If it touches the minimum of the average total cost curve, profit is zero. If it lies below, the firm makes a loss — but may still produce in the short run if price covers average variable cost.
What NCERT says
NCERT Class-12 Microeconomics (Chapter 4: The Theory of the Firm under Perfect Competition) states:
"A firm under perfect competition is a price taker. It cannot influence the market price. It can sell any amount of the good at the prevailing market price."
And later:
"The profit maximisation condition of a firm under perfect competition is that the price must be equal to the marginal cost."
That’s the core. Everything else — the shapes of cost curves, the shut-down point, the long-run equilibrium — builds on this foundation.
A final thought
Perfect competition is a model, not a photograph of reality. It strips away complexity to show how competition works in its purest form. When you later study monopoly, monopolistic competition, or oligopoly, you’ll see how each deviation from perfect competition — fewer firms, differentiated products, barriers to entry — gives firms some power over price. But the perfectly competitive firm has none. It simply responds to the market.
Perfect competition is defined by a bundle of features that together strip every individual seller of any power over price — one of those features concerns the product itself.
A homogeneous (identical) product across all sellers is the feature listed here.
Check each option against the standard list of perfect-competition features: number of sellers, product nature, price control, and entry.
Option (b) Products of all sellers are homogeneous (identical) is correct.
Perfect competition requires, among other conditions, that every seller's output be physically identical to every other seller's — a homogeneous product — so a buyer has no basis to prefer one seller over another, and price alone determines where a sale happens.
Option-by-option analysis:
- (a) A single seller controls the entire supply — incorrect; this describes monopoly, the exact opposite of perfect competition, which requires a very large number of sellers.
- (b) Products of all sellers are homogeneous (identical) — correct; this is one of the defining features of perfect competition.
- (c) Firms can influence the market price by their own decisions — incorrect; under perfect competition every firm is a price taker with no such influence.
- (d) Significant barriers prevent the entry of new firms — incorrect; perfect competition requires completely free entry and exit, the opposite of a barrier.
Option (b) Products of all sellers are homogeneous (identical) is correct.
Showing the 12 most recent of 48 on this concept.
- CBSE 2026Set MARCH1 markQ.Price taking behaviour is the distinguishing characteristic of __________ market.
›Reveal solutionSolution
The blank is filled by Perfect Competition.
Under perfect competition there are so many firms, each producing an identical (homogeneous) product, that no individual firm's output is large enough to affect the market price. Every firm therefore takes the price as given by the market and can only decide how much to produce at that price. This 'price-taking' behaviour is the key characteristic that distinguishes perfect competition from other market forms like monopoly, where the firm is a price-maker.
✓Final answerPrice-taking behaviour is the distinguishing characteristic of a perfect competition market.
- CBSE 2026Set ANNUAL1 markQ.Fill in the blank: In the ________ market a firm can enter and exit freely.
›Reveal solutionSolution
Free entry and exit is a feature of the perfectly competitive market.
In a perfectly competitive market, there is free entry and exit of firms — there are no barriers, so firms can enter when there are super-normal profits and leave when there are losses. This ensures that in the long run every firm earns only normal profit. Hence the blank is 'perfectly competitive'.
✓Final answerIn the perfectly competitive market a firm can enter and exit freely.
- CBSE 2026Set ANNUAL1 markMCQQ.Write True or False: In a perfectly competitive market firms are price-determinators.(a) True(b) False
›Reveal solutionSolution
False — firms in perfect competition are price-takers, not price-determinators.
Under perfect competition there are very many firms each selling a homogeneous product, and each firm's output is negligible relative to the market. Hence no firm can influence or set the price; it must accept (take) the price determined by overall market demand and supply. So firms are price-takers, not price-determinators. The statement is therefore False.
✓Final answerFalse — in perfect competition firms are price-takers, not price-determinators.
- CBSE 2026Set ANNUAL1 markMCQQ.In perfect competition, a firm-(a) determines price(b) accept price(c) Both(i) and(ii)(d) None of these(a) determines price(b) accept price(c) Both(i) and(ii)(d) None of these
›Reveal solutionSolution
A firm under perfect competition is a price-TAKER, accepting the market price.
Because a very large number of firms sell an identical (homogeneous) product under perfect competition, no single firm's output decision is large enough relative to the total market to influence the price. Each firm therefore faces a given, fixed market price and simply decides how MUCH to sell at that price — it 'accepts' the price rather than 'determining' it. This is the opposite of Monopoly/Oligopoly/Monopolistic Competition, where firms have at least some power to set or influence price.
✓Final answerIn perfect competition, a firm accepts price (is a price-taker) — it does not determine the price.
- CBSE 2025Set MARCH1 markMCQQ.The Equilibrium price in a perfectly competitive market when free entry and exit is allowed.(a) P = Maximum of TR(b) P = Minimum of TR(c) P = Maximum of AC(d) P = Minimum of AC
›Reveal solutionSolution
With free entry and exit, long-run equilibrium price equals the minimum of the average cost curve — option (d).
✓Final answerCorrect option: (d) P = Minimum of AC.
Reasoning (a key Kerala Plus Two DHSE economics idea):
- If price is above minimum AC, firms make supernormal profit, so new firms enter, market supply rises and price falls.
- If price is below minimum AC, firms make losses, so existing firms exit, supply falls and price rises.
- Entry/exit stops only when price exactly equals the minimum of average cost, where firms earn just normal profit (zero economic profit).
- Since a competitive firm also produces where P = MC, and MC cuts AC at its minimum, long-run equilibrium has P = MC = minimum AC.
- Options (a), (b) and (c) do not describe this zero-profit, free-entry outcome.
- CBSE 2025Set MARCH1 markQ.Fill in the blank by choosing correct answer from the bracket (Financial, Government, RBI, Perfect competition, Product, Private): Price taking behaviour is the distinguishing characteristic of __________ market.
›Reveal solutionSolution
The blank is filled by 'Perfect competition'.
A perfectly competitive market has a large number of buyers and sellers, a homogeneous product, and free entry and exit. Because each firm is very small relative to the whole market, no single firm can affect the price by changing its own output. Every firm therefore takes the market-determined price as given — this is price-taking behaviour, the distinguishing characteristic of perfect competition.
✓Final answerPerfect competition.
- CBSE 2025Set ANNUAL1 markMCQQ.Market situation where there is only one buyer is (A) Monopoly (B) Monopsony (C) Duopoly (D) None of these
›Reveal solutionSolution
A market with a single buyer is a monopsony, so the answer is (B).
Market structures are classified by the number of buyers and sellers. Monopoly means a single seller; duopoly means two sellers. When there is only one buyer facing many sellers, the market is a monopsony — the lone buyer has buying (monopsony) power over price. A common real example is a single large employer in a local labour market. Hence the situation with only one buyer is monopsony. (Non-competitive market forms sit under the Non-Competitive Markets chapter, listed without concept entries in the serving menu, so this is mapped to the nearest market-structure concept.)
✓Final answer(B) Monopsony.
- CBSE 2025Set ANNUAL1 markMCQQ.In which market is product differentiation found? (A) Pure competition (B) Perfect competition (C) Monopoly (D) Monopolistic competition
›Reveal solutionSolution
Product differentiation is found in monopolistic competition, so the answer is (D).
In perfect and pure competition, all firms sell an identical (homogeneous) product, so there is no product differentiation. In monopoly there is a single firm and a single product, so differentiation does not arise either. Monopolistic competition has many firms selling closely related but differentiated products — distinguished by brand name, design, packaging, quality or advertising (for example, different brands of toothpaste or soap). This product differentiation gives each firm some control over its price. Hence product differentiation is characteristic of monopolistic competition. (This topic falls under the Non-Competitive Markets chapter, listed without concept entries, so it is mapped to the nearest concept.)
✓Final answer(D) Monopolistic competition.
- CBSE 2025Set ANNUAL1 markMCQQ.The concept of monopolistic competition is given by (A) Hicks (B) Chamberlin (C) Mrs. Robinson (D) Samuelson
›Reveal solutionSolution
The concept of monopolistic competition was given by Chamberlin, so the answer is (B).
Edward H. Chamberlin propounded the theory of monopolistic competition in his book 'The Theory of Monopolistic Competition' (1933), analysing markets with many firms selling differentiated products. Around the same time, Joan Robinson developed the related theory of 'imperfect competition', but the specific term and framework of monopolistic competition are credited to Chamberlin. Hicks and Samuelson are associated with other areas of economics. Hence the concept is given by Chamberlin. (This belongs to the Non-Competitive Markets chapter, listed without concept entries, so it is mapped to the nearest concept.)
✓Final answer(B) Chamberlin.
- CBSE 2025Set ANNUAL1 markMCQQ.What is the type of demand curve of monopoly? (A) Inelastic (B) Elastic (C) Perfectly elastic (D) Perfectly inelastic
›Reveal solutionSolution
A monopoly faces a downward-sloping, relatively elastic demand curve, so the answer is (B) Elastic.
Under monopoly there is a single firm, so the firm's demand curve is the entire market demand curve, which slopes downward from left to right. To sell more, the monopolist must lower the price, so the curve is not perfectly elastic (a horizontal line, which belongs to perfect competition) and not perfectly inelastic (a vertical line). It is an ordinary downward-sloping demand curve, i.e. elastic/sloping rather than a straight horizontal or vertical line. Among the given options, the type of monopoly demand curve is best described as elastic (downward sloping). (Monopoly sits under the Non-Competitive Markets chapter, listed without concept entries, so it is mapped to the nearest concept.)
✓Final answer(B) Elastic.
- CBSE 2025Set ANNUAL1 markMCQQ.The single most distinguishing characteristic of perfect competition is - (A) Goods discrimination (B) Price taking behaviour of a firm (C) Excess profit (D) Price rigidity
›Reveal solutionSolution
The defining feature of perfect competition is that firms are price-takers, so (B) is correct.
In the RBSE/CBSE Class-12 chapter on the firm under perfect competition, the market has a very large number of buyers and sellers trading a homogeneous (identical) product, with free entry and exit and perfect information. The combined result of these conditions is that no individual firm can affect the market price — the price is set by overall market demand and supply, and each firm must take that price as given.
This price-taking behaviour is the single most distinguishing characteristic of perfect competition. Price discrimination and price rigidity belong to imperfect markets, and excess (super-normal) profit is competed away in the long run.
✓Final answer(B) Price taking behaviour of a firm — the single defining feature of perfect competition.
- CBSE 2025Set ANNUAL1 markQ.Fill in the blank: Free entry and exit of the firm implies that the market price will always be equal to ________.
›Reveal solutionSolution
The blank is the minimum of average cost — free entry and exit pushes long-run price to minimum AC, leaving only normal profit.
In the RBSE/CBSE Class-12 chapter on the firm under perfect competition, free entry and exit is a key feature. If existing firms earn super-normal profit, new firms enter, raising supply and lowering price; if firms make losses, some exit, reducing supply and raising price. This process continues until every firm earns only normal profit (zero economic profit).
At that long-run position, price (P) equals the minimum of the average cost curve. So free entry and exit ensures the market price settles at the minimum average cost.
✓Final answerFree entry and exit implies the market price will always be equal to the minimum of average cost (minimum AC), so firms earn only normal profit.
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