CHANGE IN QUANTITY DEMANDED

A change in quantity demanded, is otherwise known as movement along a particular demand curve that is only influenced by price. When there is a change in the quantity demanded, the demand curve does not shift. This is because the price of the commodity is the only cause of a change in the quantity demanded while other factors remain unchanged.

From the above diagram, as the price falls from #50 to #30, the quantity demanded increases from 60 to 80 units,

Hence movement along the same demand curve took place from A to B.

Further decrease or increase in price will also affect the movement along the same

demand curve.

CHANGES IN DEMAND

When different quantities of goods and services are demanded at a particular price, it is called a change in demand. It is caused by those factors that generally affect the demand of a commodity other than the price of the commodity; For example changes in taste and fashion, changes in income etc Change in demand shows a shift of the demand curve to an entirely new position. A shift of the demand curve to the right is termed an increase in demand while a shift of the demand curve to the left is a decrease in demand.

EVALUTION

State three factors responsible for the change in demand.
What is change in quantity demand?

CHANGES IN QUANTITY SUPPLIED

Change in quantity supplied is only influenced by price. It involves movement along the same supply curve

CHANGE IN SUPPLY

Change in supply is caused by factors other than the price of the commodity. It involves a bodily shift of the supply curve either to the right (increase in supply) or to the left.

EVALUATION

What is change in quantity supplied?
State the factors responsible for change in supply.

EFFECTS OF CHANGES IN DEMAND AND SUPPLY ON EQUILIBRIUM PRICE AND QUANTITY

Changes in demand and supply lead to a change in the equilibrium price. Once there is any change in either demand or supply, the initial equilibrium will be disrupted and a new equilibrium will be created. The market equilibrium price can be affected in the following ways.

Effects of increase in demand

Increase in the equilibrium price from P₁to P₂
Increase in the equilibrium quantity from Q₁ toQ₂

Effects of Decrease in Demand

Decrease in the equilibrium price from P₁ to P₂
Decrease in the equilibrium quantity from Q₁to Q₂

Effects of Increase in Supply

Decrease in the equilibrium price from P₁ to P₂
Increase in the equilibrium quantity from Q₁to Q₂

Effects of Decrease in Supply

Increase in the equilibrium price from P₁ to P₂
Decrease in the equilibrium quantity from Q₁to Q₂

EVALUATION QUESTION

What is the equilibrium quantity?
Illustrate with a diagrammatic sketch the market situation at a price lower than the equilibrium price”
Explain with the aid of diagrams how the market equilibrium price is affected by the combined effects of:

Increase in demand and increase in supply.

b. Decrease in demand and decrease in supply.

Increase in demand and decrease in supply.

GENERAL EVALUATION QUESTIONS

Distinguish between fixed cost and variable cost.
Under what condition will a perfectly competitive firm maximize profit.
Describe each of the following; (a) abnormal demand ( b) Effective demand

What is a public corporation.
Explain the causes of a declining population.

WEEKEND ASSIGNMENT

At the equilibrium price, quantity demanded is (a) greater than quantity supplied (b) equal to quantity supplied (c) less than quantity supplied (d) equal to excess supply
If the government fixes a price of a commodity above the equilibrium price, the quantity supplied will be (a) less than the quantity demanded (b) equal to the quantity demanded (c) greater than the quantity demanded (d) equal to zero
The market price of a commodity is normally determined by the (a) law of demand (b) interaction of the forces of demand and supply (c) total number of people in the market (d) total quantity of the commodity in the market
The gap between demand and supply curves below the equilibrium price indicates (a) excess demand (b) excess supply (c) equilibrium quantity (d) equilibrium price
If prices fall below the equilibrium (a) demand will equal supply (b) demand will be greater than supply (c) supply will be greater than demand (d) quantity supplied will be zero

SECTION B

Given the demand and supply function for a crate of eggs as follows: Qd = 12 –2p; Q = 3+1p Determine the equilibrium price and quantity

What is the excess supply at the price of N50?