Because price elasticity (of supply or demand) is a relatively simple concept, there are not that many different types of essay questions that can be asked.
Price elasticity is a measure of how much the quantity demanded (or supplied) of a product goes up or down when the price of the product changes. Because the concept is this simple, the only really good type of essay question (for a basic level course in economics) is one that asks why certain goods are highly elastic and others are not.
So, you could simply ask
- Describe the factors that cause demand for a product to be elastic and explain why each factor leads to elastic demand. (You could do the same for supply or for inelastic products.)
Or you could say
- Pick two products and explain which one will have a greater price elasticity of demand and why this will be the case.