Distinguish between change in demand and change in quantity demanded. Illustrate by use of a diagram?

Change in demand refers to a shift in the entire demand curve, caused by factors such as changes in consumer preferences, income, prices of related goods, or expectations. This results in a new equilibrium price and quantity in the market. On the other hand, change in quantity demanded refers to movement along the demand curve, caused by a change in the price of the good or service.

To illustrate this concept, let's consider the market for smartphones. Suppose there is an increase in consumer income, leading to a higher demand for smartphones. This would cause the demand curve to shift to the right, as shown in the diagram below:

[Diagram showing a shift in the demand curve to the right]

On the other hand, if the price of smartphones decreases, leading to an increase in the quantity demanded, this would result in a movement along the demand curve, as shown in the diagram below:

[Diagram showing a movement along the demand curve due to a change in price]

In summary, change in demand refers to a shift in the entire demand curve, while change in quantity demanded refers to movement along the demand curve due to a change in price.