National Economics Challenge Practice Test

In a perfectly competitive market, firms are price takers and will produce at the profit-maximizing quantity where marginal cost equals marginal revenue. When firms are producing at this point with a market price at P2, the implication is that they are covering their average costs, leading to zero economic profits in the long run.

In the long run, if firms in a perfectly competitive industry are earning any positive economic profits, it signals an opportunity for other firms to enter the market. However, if all firms are operating at a point where the price equals average total costs, this indicates that they earn zero economic profits. In such scenarios, no incentive exists for new firms to enter or for existing firms to leave the market, as profits are neither being made nor lost.

Thus, the long-run equilibrium in a competitive market results in firms earning zero economic profits, confirming that they can cover all their costs, including opportunity costs, but they do not earn excess returns. This outcome reinforces the notion that competition drives prices down to the level of average costs in the long run, ensuring that firms cannot sustain economic profits without encouraging new entrants.