The Law Of Supply Explained for SHS 1 Economics (Semester 2, Week 2)

Why do producers supply more goods when prices increase? The answer lies in one of the most important principles in economics: the Law of Supply.

What You Will Learn

• The meaning of the Law of Supply
• The relationship between price and quantity supplied
• The meaning of supply schedules, supply curves, and supply functions
• The key assumptions behind the Law of Supply
• Real-world examples from Ghana

Main Explanation

The Law of Supply is an economic principle that explains how producers respond to changes in prices. It states that all things being equal, when the price of a product rises, producers are willing to supply more of that product. When the price falls, producers are willing to supply less.

This principle shows a direct or positive relationship between price and quantity supplied. Higher prices provide greater incentives for producers because they can earn higher profits.

A supply schedule presents this relationship in a table format by showing quantities supplied at different prices.

Price Of Rice	Quantity Supplied
1	8
2	16
3	24
4	32
5	40

The table demonstrates that as the price of rice rises, producers supply more rice. This relationship produces an upward-sloping supply curve.

A supply curve is drawn using data from a supply schedule. Quantity supplied is placed on the horizontal axis, while price is placed on the vertical axis.

Economists also use supply functions to describe supply mathematically. A supply function takes the form:

Q = f(P)

An example is:

Qs = 50 + 0.25P

This formula shows how quantity supplied changes whenever price changes.

Several important ideas help explain the Law of Supply:

• Positive Relationship: Price and quantity supplied move in the same direction.
• Ceteris Paribus: Other factors such as technology and taxes remain unchanged.
• Profit Motive: Producers seek to maximise profits.
• Time Horizon: Supply adjustments are easier in the short run than in the long run.

The Law of Supply can be seen in many sectors of Ghana’s economy. Cocoa farmers may increase production when cocoa prices rise. Gold mining companies may expand operations when gold prices increase. Poultry farmers may produce more chickens and eggs when demand and prices rise.

Key Concepts Of The Law Of Supply

Concept	Description	Importance
Supply Schedule	Table showing price and quantity supplied	Provides supply data
Supply Curve	Graph showing supply relationship	Visualises supply behaviour
Supply Function	Mathematical expression of supply	Allows calculations
Profit Motive	Desire to earn profits	Drives production decisions

Worked Examples

Example 1

Problem: Calculate the quantity supplied when Qs = 50 + 0.25P and P = 120.

1. Substitute P = 120 into the equation.
2. Calculate 0.25 × 120 = 30.
3. Add 50 + 30.

Answer: Qs = 80 units.

Example 2

Scenario: International cocoa prices increase significantly.

Explanation: Cocoa farmers are likely to increase production because higher prices provide opportunities for greater profits. This demonstrates the Law of Supply.

Why This Topic Matters

The Law of Supply helps explain how producers make decisions in response to price changes. Understanding this principle enables learners to analyse market behaviour, business decisions, agricultural production, and economic activities within Ghana and around the world.

Quick Practice

• State the Law of Supply.
• Explain the meaning of ceteris paribus.
• Describe how higher prices influence quantity supplied.

Summary

The Law of Supply states that producers supply more of a product when its price rises and less when its price falls, assuming all other factors remain constant. Supply schedules, supply curves, and supply functions help explain this relationship. The law is driven by profit motives and can be observed in sectors such as cocoa farming, gold mining, oil production, Shea butter production, and poultry farming in Ghana.