Question

What is the SI unit of modulus of elasticity?
A) $pascal$
B) $kg.m/{s^2}$
C) $N/m$
D) $kg.m$

Answer 1

Hint: SI unit, also called the international system of unit is the only system of measurement with official status in almost every country in the world. There are seven SI base units namely, second (s), meter (m), kilogram (kg), ampere (A), kelvin (K), mole (mol), and candela (cd). Other than this all the SI units are SI derived units. Pascal is also an SI derived unit of pressure which is used to measure internal pressure.

Complete answer:
First let us define the modulus of elasticity. The modulus of elasticity is the measure of an object’s or substance’s resistance to being deformed elastically when stress is applied. The modulus of elasticity is a constant for a specific material. A higher modulus of elasticity means stiffer material. The modulus of elasticity is defined as the ratio of the stress in the material and the strains caused by the force.
$\therefore E = \dfrac{\sigma }{\varepsilon } = cons$
Where stress is the force causing the deformation divided by the area to which the force is applied which is the definition of pressure and strain is the ratio of the change in some parameter caused by the deformation to the original value of the parameter. If stress is measured in pascal, then since the strain is a dimensionless measure, the SI unit of $E$ will be pascal. The symbol of the SI unit pascal is $Pa$ .

Note: Not to be confused between pressure and stress let us define both the terms. The pressure is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. On the other hand, the stress is the physical quantity that expresses the internal forces that neighboring particles of a continuous material exert on each other.