Basic purpose of this lecture is to presentation on Elasticity and its Application. This lecture briefly explain on what is elasticity and what kinds of issues can elasticity help us understand. Here also describe on the price elasticity of demand and how is it related to the demand curve how is it related to revenue and expenditure. Finally explain what is the price elasticity of supply and how is it related to the supply curve. This lecture also focus on the income and cross-price elasticities of demand and Variety of Supply Curves, Elasticity and changes in equilibrium.