Chapter 2: Principles of Demand and Supply in Commerce

Basic Definition of Demand and Supply           
Demand is the quantity of a good consumers are willing to buy at a given price, while supply is the quantity producers are willing to sell.

Demand refers to the quantity of a good or service that consumers are both willing and able to purchase at various price levels during a specific period. It is not just about desire but also about purchasing power. The relationship between price and quantity demanded is inverse when prices rise, demand tends to fall, and when prices fall, demand usually increases. This principle is called the Law of Demand.

• Example: If the price of mangoes falls from ₹100 per kg to ₹60 per kg, more consumers may decide to buy mangoes, thereby increasing the quantity demanded.

Supply

Supply refers to the quantity of a good or service that producers are willing and able to offer for sale at various price levels during a given period. Unlike demand, the relationship between price and supply is usually direct when the price rises, producers are motivated to supply more to increase revenue, while lower prices discourage production. This is known as the Law of Supply.

• Example: If the market price of wheat increases from ₹20 per kg to ₹30 per kg, farmers are more likely to allocate land and resources to wheat cultivation, thereby increasing supply.

Key Contrast

• Demand represents consumer perspective: what and how much buyers want.
• Supply represents producer perspective: what and how much sellers provide.

This interaction of demand and supply determines the market equilibrium price and quantity.

Concept

Definition

Example

Demand

Quantity of a good or service consumers are willing and able to buy at a given price

At ₹50 per kg, consumers demand 100 kg of rice in a market

Supply

Quantity of a good or service producers are willing and able to sell at a given price

At ₹50 per kg, farmers are willing to supply 80 kg of rice

Determinants of Demand

Income, tastes, population, price of substitutes/complements

Rising income increases demand for smartphones

Determinants of Supply

Production cost, technology, government policies, natural conditions

Favourable weather increases wheat supply

Market Interaction

Demand and supply together determine equilibrium price and quantity

When demand > supply, prices rise; when supply > demand, prices fall