Final answer:
An increase in income can make electric cars more affordable, leading to a higher demand for them. This is graphically shown as a shift in the demand curve to the right, indicating a higher quantity demanded at each price level, adhering to the law of demand.
Step-by-step explanation:
The law of demand indicates that there is an inverse relationship between the price of a good and the quantity demanded, assuming ceteris paribus, meaning all other factors are held constant.
When considering the demand for electric cars, if people's incomes increase due to economic expansion, they generally have more purchasing power. This increase in income tends to make electric cars more affordable, likely leading to an upward shift in the demand curve from the original demand curve D0.
Graphically, this shift is represented by a new demand curve, D1, to the right of the original demand curve, indicating a higher quantity demanded at each price level.