Principle objective of this lecture is to present on Energy. Energy is the ability to do work. It cannot be created or destroyed. In physics, energy is a property of objects which can be transferred to other objects or converted into different forms. The “ability of a system to perform work” is a common description, but it is misleading because energy is not necessarily available to do work. Here briefly present on the Law of Conservation of Energy. Finally focus on types of energy: Kinetic, Potential, Mechanical wave, Magnetic etc.