How does a firm’s demand curve appear in a perfect competition market structure?

In a perfectly competitive market structure, a firm’s demand curve is perfectly elastic. This means that the firm is a price taker and can sell any quantity of goods it wishes at the prevailing market price, but it cannot influence that price. If the firm tries to charge a price higher than the market price, consumers will purchase from other firms that sell at the market price instead, leading to zero sales for the higher-priced firm.

This perfectly elastic demand is a result of the presence of many sellers and buyers in the market, where the products offered by different firms are homogeneous or identical. Thus, the firm faces a horizontal demand curve at the market price level, indicating that there is an infinite quantity demanded at that price, but none at a higher price.

In contrast, a downward sloping demand curve is characteristic of monopolistic or monopolistically competitive markets, where firms have some control over pricing. A perfectly inelastic demand curve would indicate that consumers will buy the same quantity regardless of price changes, which is not the case in a competitive market. Lastly, while market competition does influence a firm's demand, it is the elasticity of that demand directly reflecting the competitive nature of the market that is most relevant in this context.