A Change in Quantity Supplied

                A Change in quantity supplied is a movement along the same supply curve caused by a change in price only. As the price of normal good increases, the quantity supplied increases. This is referred to as an extension or expansion in supply. When the price of the good decreases, the

This is quantity supplied will also decreases referred to as a contraction in supply.

Thus a change in quantity supplied is a movement along a given supply curve either quantity supplied is a upward or downward caused by changes in price of a good, while and other factors that affect supply are held constant.

A Change in Supply

              A change in supply is a complete movement of the supply curve either to the right or to the left caused by all factors that affect supply except the price of the good. If the shift is to the right, it is called an increase in supply while a shift to the left is called a decrease in supply-

The figure below illustrate an increase in supply and a decrease in supply-

1. An increase in supply

                 An increase in supply is a complete shift of the supply curve of a good to the right with the price remaining unchanged. This increase is caused by a positive effect of factors that are responsible for an increase in producer's desires to supply more of the good. For instance, improvement in technology, favourable weather condition, low cost of production, subsidy by the government, amongst others will increase the amount of goods supplied in the market.

In the figure above a Shift of the supply curve from SS to

S₁S₁ is an increase in supply-More is supplied at the same price of 4000frs/kg

1. A decrease in supply:

               This is a complete shift of a supply curve of a good to the left, while the price of the good remains unchanged. This decrease in supply is caused by unfavourable change of factors that affect supply such as a bad weather condition, high taxes on producers, poor technique of production, high cost of production, amongst others.

In the figure above a Shift of the supply curve from SS to S₂S₂ is a decrease in supply. Less is supplied at the same price of 4000 FRS