Extension / Expansion of Demand:
1. Extension of demand refers to a rise in demand due to fall in price. Other factors remaining constant.
2. It is a case of variation in demand.
3. Extension in demand takes place due to a fall in price, other things remaining constant.
4. When there is extension in demand the demand curve moves downward on the same demand curve.
Increase in Demand:
1. Increase in demand takes place when more quantity is demanded at the same price.
2. It is a case of changes in demand.
3. Increase in demand takes place due to change in other factors, price remaining constant such as change in income, taste, habits, population, etc.
4. When there is a increase in demand the demand curve shifts to the right of the otiginal demand curve.
