**Supply Curve of a Perfectly Competitive Firm**

The supply curve of a perfectly competitive firm is a graphical representation of the relationship between the quantity of output a firm is willing to produce and sell at different market prices, while assuming all other factors remain constant. In a perfectly competitive market, firms are price takers, meaning they have no control over the market price and must accept it as given.

**Factors Determining the Supply Curve:**

The supply curve of a perfectly competitive firm is determined by several factors, including:

**1. Marginal Cost Curve:**
The marginal cost curve represents the additional cost incurred by the firm for producing one more unit of output. In the short run, the supply curve of a perfectly competitive firm is directly related to its marginal cost curve. As long as the market price exceeds the marginal cost of production, the firm will be willing to increase its output and supply more units to the market. Therefore, the marginal cost curve serves as the supply curve for a perfectly competitive firm in the short run.

**2. Average Cost Curve:**
The average cost curve represents the average cost per unit of output. In the long run, the supply curve of a perfectly competitive firm is determined by its average cost curve. If the market price is above the average cost of production, the firm will be earning profits and will be motivated to increase its output and supply. Conversely, if the market price falls below the average cost, the firm will incur losses and may reduce its output or exit the market. Thus, the average cost curve also plays a crucial role in determining the supply curve of a perfectly competitive firm in the long run.

**3. Relationship with the Demand Curve:**
The supply curve of a perfectly competitive firm is not the same as its demand curve. The demand curve faced by a perfectly competitive firm is perfectly elastic, as the firm can sell any quantity of output at the prevailing market price. On the other hand, the supply curve represents the firm's willingness to produce and sell at different price levels. In a perfectly competitive market, the supply curve is upward sloping, indicating that as the price increases, the firm is willing to supply more units of output. This is in contrast to a perfectly elastic demand curve, which is a horizontal line indicating that the firm can sell any quantity at the given market price.

**Conclusion:**
In summary, the supply curve of a perfectly competitive firm is determined by its marginal cost curve in the short run and its average cost curve in the long run. The supply curve represents the firm's willingness to produce and sell at different price levels, while the demand curve faced by the firm is perfectly elastic. Understanding the determinants and characteristics of the supply curve is essential for analyzing the behavior of perfectly competitive firms in response to changes in market conditions.

Marginal cost curve