Which one of the following is not a unit of Young’s modulus?
A unit is a standard measure used to express physical quantities like length mass and time. It provides a reference for consistency in measurements. Units are classified into fundamental and derived types and systems like SI ensure global uniformity. Accurate units are essential in science engineering and daily life applications.
Class 11 Physics Chapter 8 explains mechanical properties of solids including stress strain relationships Young’s modulus bulk modulus and shear modulus. It discusses elasticity Hooke’s law factors influencing elasticity and practical applications in engineering and construction. Understanding these concepts is crucial for designing materials and structures capable of withstanding various forces effectively.
Young’s modulus is defined as stress divided by strain, where:
Stress = Force / Area (unit: Nm⁻² or Pascal)
Strain is dimensionless, so Young’s modulus has the same unit as stress, i.e., Nm⁻², Pascal (Pa), or derived units like megapascals (MPa).
Now, let’s analyze the options:
– Nm⁻¹: This represents force per unit length, not a valid unit for Young’s modulus.
– Nm⁻²: Correct unit of Young’s modulus.
– dyne cm⁻²: A valid unit (CGS system).
– mega pascal: A legitimate unit (1 MPa = 10⁶ Pa).