The expanding abilities of different solid materials are different. The co-efficient of expansion of a solid refers to its expanding abilities.

Types of co-efficient of expansion

·         Co-efficient of linear expansion(α) or linear expansivity

·         Co-efficient of Areal expansion(β) or areal expansivity

·         Co-efficient of volume expansion(γ) or volume expansivity

·         Co-efficient of expansion refers to the material of solid,not the object.

For example,

Steel Rod Material-Steel

Object-Rod

α belongs to steel not rod.