The optimal range of output for a perfectly competitive firm is

The optimal range of output for a perfectly competitive firm is where the firm's marginal cost (MC) is equal to its marginal revenue (MR) and is also equal to or greater than its average variable cost (AVC). In a perfectly competitive market, firms are price takers and must sell their products at the market price. Therefore, the marginal revenue (MR) for a perfectly competitive firm is equal to the market price. The marginal cost (MC) of producing an additional unit of output is the additional cost of producing that unit. The perfectly competitive firm will continue to produce output as long as the marginal revenue (MR) is greater than or equal to the marginal cost (MC). When the firm produces output up to the point where MC equals MR, it is operating at the optimal range of output. In this range of output, the firm is maximizing its profits, because any increase or decrease in production would lead to a decrease in profits. The firm's average variable cost (AVC) should also be taken into account to ensure that it is covering its variable costs and operating efficiently. If the firm produces output at a level where MC is rising above MR, it means that the cost of producing an additional unit is higher than the revenue it generates, leading to a decrease in profits. Conversely, if the firm produces output at a level where MC is falling below MR, it means that it could increase profits by producing more output. Therefore, the optimal range of output for a perfectly competitive firm is where MC equals MR and is equal to or greater than AVC.