Q.Can there be a positive level of output that a profit-maximising firm produces in a competitive market at which market price is not equal to marginal cost? Give an explanation.

No, there cannot be a positive level of output that a profit-maximising firm produces in a competitive market at which market price is not equal to marginal cost.

For a firm operating in a perfectly competitive market, the profit-maximising condition is that Marginal Revenue ($MR$) must equal Marginal Cost ($MC$). Since a competitive firm is a price-taker, its Marginal Revenue is always equal to the market price ($P$). Therefore, the profit-maximising condition simplifies to $P = MC$.

Here's why $P$ must equal $MC$ at any positive profit-maximising output:

1. If $P > MC$: This means that producing an additional unit of output would add more to the firm's total revenue (by $P$) than to its total cost (by $MC$). In this situation, the firm can increase its total profit by increasing its output. It will continue to increase output until $P = MC$.
2. If $P < MC$: This means that the last unit produced added more to the firm's total cost (by $MC$) than to its total revenue (by $P$). In this situation, the firm can increase its total profit by reducing its output. It will continue to decrease output until $P = MC$. …

In a perfectly competitive market, a firm's primary objective is to maximise its economic profit. Profit ($\pi$) is defined as total revenue ($TR$) minus total cost ($TC$). To maximise profit, a firm must choose the level of output where the additional revenue from producing one more unit (marginal revenue, $MR$) is exactly equal to the additional cost of producing that unit (marginal cost, $MC$). This is the fundamental profit-maximisation condition: $MR = MC$.

For a firm operating in a perfectly competitive market, there are specific characteristics that simplify this condition. A competitive firm is a price taker, meaning it cannot influence the market price ($P$) of its product. It sells all its output at the prevailing market price. Consequently, the revenue generated from selling one additional unit of output (marginal revenue) is simply equal to the market price. Thus, for a perfectly competitive firm, $MR = P$.

Substituting this into the general profit-maximisation condition, we get the specific rule for a competitive firm: $P = MC$.

Let's understand the intuition behind this rule:

• If the market price ($P$) is greater than the marginal cost ($MC$) of producing the last unit ($P > MC$), it means the firm earns more revenue from that unit than it costs to produce it. In this situation, the firm can increase its total profit by producing and selling more units.
• If the market price ($P$) is less than the marginal cost ($MC$) of producing the last unit ($P < MC$), it means the firm is incurring a loss on that unit. In this situation, the firm can increase its total profit (or reduce its losses) by producing and selling fewer units.
• Therefore, to maximise profit, the firm must adjust its output level until the point where the market price exactly equals the marginal cost ($P = MC$). At this point, there is no further opportunity to increase profit by changing output.