YOUNG'S MODULUS

"The ratio of stress to the longitudinal strain is called Young's modulus."

Mathematically: -

Young's Modulus = Stress / Longitudinal Strain

OR

Y = s / e .......... (i)

But s = F / A and e = DL / L

Putting these values in equation (i)

Y =( F / A) / (DL / L) OR Y = F L / A DL

In S.I. system unit of ‘Young's Modulus is N / m²