Understanding Perfectly Elastic Supply

A perfectly elastic supply curve is a concept in economics that describes a situation where producers are willing to supply any quantity of a good or service at a specific price, but none at a price even slightly lower than that specific price. This is an extreme case of price elasticity of supply.

Analyzing Statement (i): A Horizontal Supply Curve

Statement (i) says that a perfectly elastic supply curve is a horizontal supply curve. Let's consider what a horizontal supply curve represents on a standard price-quantity graph. If the supply curve is horizontal, it means that at a certain price level, let's call it P*, the quantity supplied can be anything from zero up to potentially a very large amount. However, if the price falls below P*, even by a tiny amount, the quantity supplied drops to zero. This characteristic fits the definition of perfectly elastic supply.

Graphically, a horizontal supply curve looks like this:

Price
|
| S (Perfectly Elastic Supply)
|-------------------- Quantity
P*|
|
|
+------------------------------
0

At price P*, any quantity is supplied. Below P*, quantity supplied is zero.

Analyzing Statement (ii): Price Elasticity of Supply = Infinity

Statement (ii) says that for a perfectly elastic supply curve, the Price Elasticity of Supply (PES) equals infinity. The formula for Price Elasticity of Supply is:

$$ \text{PES} = \frac{\text{\% Change in Quantity Supplied}}{\text{\% Change in Price}} $$

In the case of perfectly elastic supply, producers are willing to supply any amount at a single specific price. This means that a tiny, almost zero, percentage change in price (or the willingness to supply infinite quantity at one price vs zero below that price) can lead to an infinitely large percentage change in the quantity supplied.

Consider the horizontal supply curve at price P*. If the price is P*, any quantity is supplied. If the price is slightly less than P*, the quantity supplied is 0. A minute drop in price causes quantity supplied to fall from some positive value to zero, representing a massive percentage change in quantity for a near-zero percentage change in price. This leads to an infinite PES.

For practical purposes, when the denominator (% Change in Price) approaches zero while the numerator (% Change in Quantity Supplied) is a finite positive number, the PES approaches infinity.

Connecting Statements (i) and (ii)

As we have seen, a horizontal supply curve precisely illustrates a situation where the price elasticity of supply is infinite. A horizontal line at a given price shows that quantity supplied is extremely sensitive to price; any price change away from that specific level results in an infinite percentage change in quantity supplied (from some amount to zero, or vice-versa, relative to the tiny price change).

Therefore, both statements accurately describe a perfectly elastic supply curve.

Evaluating the Options

• Only (i): Incorrect, as (ii) is also true.
• Neither (i) nor (ii): Incorrect, as both are true.
• Both (i) and (ii): Correct, as both characteristics define perfectly elastic supply.
• Only (ii): Incorrect, as (i) is also true and is the graphical representation of the concept leading to (ii).

A perfectly elastic supply curve is indeed a horizontal supply curve, and for such a curve, the price elasticity of supply is equal to infinity.

Revision Table: Key Elasticity Concepts

Additional Information on Elastic Supply Concepts

Understanding different types of price elasticity of supply is crucial in economics. It helps us predict how producers will react to price changes. The elasticity is influenced by factors such as the availability of inputs, time horizon for production adjustments, and the ability to store goods.

• Time Horizon: In the very short run, supply is often fixed (perfectly inelastic) because producers cannot immediately change the quantity produced. In the long run, supply tends to be more elastic as producers have more time to adjust production levels, build new factories, or exit the market.
• Availability of Inputs: If inputs (like labor, raw materials) are readily available and can be easily increased, supply will be more elastic. If inputs are scarce or specialized, supply will be less elastic.
• Flexibility of Production: If a firm can easily switch between producing different goods, its supply will be more elastic.

The concept of perfectly elastic supply, while an extreme case, helps illustrate the boundary of supply responsiveness. It is often approximated in situations where inputs are unlimited at a given price, such as the long-run supply of goods from industries that can easily expand by replicating existing facilities.