(

*Y*) or the

*modulus of elasticity*, is defined as

**Modulus of elasticity** = stress / strain

**The modulus has the same units as stress. A large modulus means that a large stress is requird to produce a given strain - the object is rigid**

Accordingly, *Y* = ( F/A ) / ( Δ/L_{0} ) = FL_{0} / AΔL

Its SI unit is **Pa**. Unlike the constant *k* in Hooke's Law, the value *Y* depends only on the material of the wire or rod], and not on its dimensions or configuration. Consequenty, Young's modulus is an important basic measure of the mechanical behavior of materials.