Youngs Modulus Elastic Modulus - Definition, Formula, Unit, FAQs

Youngs Modulus Elastic Modulus - Definition, Formula, Unit, FAQs

Team Careers360Updated on 02 Jul 2025, 04:41 PM IST

Elastic constants are the values that determine the amount of deformation caused by a certain stress system acting on a material. Elastic constants come in a variety of forms, including:
Bulk modulus is a term that refers to the amount of (K)
Young’s modulus or elastic modulus, often known as the modulus of elasticity, is a measure of the elasticity of a material (E)
The Poisson Ratio (µ)
Modulus of stiffness or shear modulus (G)

Youngs Modulus Elastic Modulus - Definition, Formula, Unit, FAQs
Youngs Modulus Elastic Modulus

What is young’s modulus of elasticity? Or define young’s modulus or elastic modulus

The mechanical property of material to tolerate compression/elongation with its length is defined as Young’s modulus, also called as modulus of elasticity. Also, young’s modulus is defined as the ratio of stress to strain.

It’s symbolised by letters E or Y.

Young’s modulus is a mechanical property of linear elastic solids such as rods, wires, and other similar objects. Other quantities, such as Bulk modulus and shear modulus, can be used to determine a material's elastic properties, but Young’s modulus is the most widely utilised. When a specific load is applied to a solid object, it deforms. When the pressure is removed from an elastic object, the body returns to its previous shape. Beyond a small degree of distortion, many materials are not linear and elastic. Only linear elastic materials have a constant Young’s modulus.

Young’s modulus formula is a mathematical formula that is used to calculate the modulus of

E=σ/ϵ

From Other Quantities: E=Modulus Young's Formula

=FL0/AΔL

ϵ = ΔL/L0

  • Young’s modulus formula E in Pa
  • ? is the stress in Pa that is applied uniaxially.
  • ϵ is the proportionate deformation or the strain
  • The object under strain exerts a force called F.
  • A is the cross-sectional area of the actual cross-section.
  • L denotes the length variation.
  • The true length is L0.
SI Young’s modulus unitsPa
Imperial UnitPis
DimensionML^-1T^-2


YOUNG’S MODULUS= STRESS/STRAIN
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YOUNG’S MODULUS

The ratio of stress and strain, which corresponds to the material's stress, determines the Young’s modulus of such a material. The relationship is seen in the table below.

E =, where E is the material's Youngs formula in N/m2, is the stress applied to the material, and is the strain corresponding to the applied stress in the material. With the value of Young’s modulus for a material, the rigidity of a body may be determined. This is because it reveals the body's ability to resist deformation when force is applied.

  1. Young’s modulus of steel 200,
  2. glass has a value of 65,
  3. wood has a value of 13, and
  4. plastic (polystyrene) has a value of 3.

Young’s modulus or elastic modulus factor-

We can assert that steel is more robust in nature than wood or polystyrene by studying its modulus of elasticity units, since it has a lower tendency to deform under applied load. Young’s modulus is also used to calculate how much a material will deform when subjected to a given load.

Another thing to remember is that the lower the Young’s modulus of a material, the greater the deformation experienced by the body, and in the case of clay and wood, this distortion might vary within a single sample. One part of the clay sample deforms more than the other, whereas a steel bar deforms evenly all the way around.

Also Read:

Elasticity definition or define elasticity or what is elasticity?

Elasticity is a term used in economics to describe how the aggregate quantity demanded of a good or service changes in response to price changes in that good or service. If the quantity demand for a product fluctuates more than proportionally when the price changes, the product is said to be elastic. Modulus of elasticity formula is ratio of stress by strain.

Also check-

NCERT Physics Notes:

Commonly Asked Questions

Q: What is Young's modulus and why is it important?
A:
Young's modulus is a measure of a material's stiffness or resistance to elastic deformation under load. It's important because it helps engineers and scientists understand how materials will behave under stress, allowing them to select appropriate materials for various applications in construction, manufacturing, and product design.
Q: How is Young's modulus different from other elastic moduli?
A:
Young's modulus specifically relates to longitudinal stress and strain in a material. Other elastic moduli include shear modulus (relating to shear stress and strain) and bulk modulus (relating to volumetric stress and strain). Young's modulus is unique in that it describes a material's behavior under tension or compression along a single axis.
Q: Can Young's modulus be negative?
A:
No, Young's modulus cannot be negative for real materials. A negative Young's modulus would imply that a material expands when compressed and contracts when stretched, which violates the principles of thermodynamics and is not observed in nature.
Q: Why do some materials have a higher Young's modulus than others?
A:
Materials with higher Young's moduli have stronger interatomic or intermolecular bonds. These stronger bonds resist deformation more effectively, resulting in a stiffer material. For example, metals typically have higher Young's moduli than polymers due to their stronger metallic bonds.
Q: How is Young's modulus related to Hooke's Law?
A:
Young's modulus is directly related to Hooke's Law. Hooke's Law states that stress is proportional to strain in the elastic region. The constant of proportionality in this relationship is Young's modulus. Thus, Young's modulus can be thought of as a measure of how well a material obeys Hooke's Law.

Frequently Asked Questions (FAQs)

Q: What's the significance of Young's modulus in the study of biomechanics?
A:
In biomechanics, Young's modulus is crucial for understanding how biological tissues respond to mechanical forces. It's used to model the behavior of bones, tendons, ligaments, and blood vessels. Understanding the Young's modulus of these tissues is important for developing medical devices, prosthetics, and treatments for musculoskeletal disorders.
Q: How does Young's modulus affect the speed of sound in a material?
A:
The speed of sound in a material is directly related to its Young's modulus. The formula for the speed of sound in a solid is v = √(E/ρ), where E is Young's modulus and ρ is the density. Therefore, materials with higher Young's moduli tend to transmit sound faster, assuming similar densities.
Q: Why is Young's modulus important in the design of springs?
A:
Young's modulus is crucial in spring design because it determines how much a spring will deform under a given load. Springs made from materials with higher Young's moduli will be stiffer and deform less for a given force. This information is essential for designing springs that will function correctly in various applications.
Q: How does the concept of Young's modulus apply to biological materials?
A:
Young's modulus is relevant to biological materials like bones, tendons, and blood vessels. It helps in understanding how these tissues respond to mechanical stresses. For example, the Young's modulus of bone helps determine its ability to resist deformation and fracture. In tissue engineering, matching the Young's modulus of artificial scaffolds to natural tissues is crucial for successful integration.
Q: What's the relationship between Young's modulus and a material's ability to store elastic energy?
A:
A material's ability to store elastic energy is related to its Young's modulus. Materials with higher Young's moduli can store more elastic energy per unit volume for a given strain. This is why materials like steel are often used in applications where energy storage is important, such as in springs or in the construction of flexible structures.
Q: Can liquids have a Young's modulus?
A:
Strictly speaking, liquids do not have a Young's modulus. Young's modulus is a property of solid materials that resist deformation. Liquids, by definition, flow and change shape easily under stress, so they don't exhibit the kind of elastic behavior described by Young's modulus. However, liquids do have a bulk modulus, which describes their resistance to uniform compression.
Q: Why do some materials, like rubber, seem to violate Hooke's Law?
A:
Materials like rubber exhibit non-linear elastic behavior, which appears to violate Hooke's Law. This is because their stress-strain relationship is not linear, even at low strains. For such materials, Young's modulus is not constant and changes with the applied stress. This behavior is due to the unique molecular structure of rubber, which allows for large, reversible deformations.
Q: How does Young's modulus relate to a material's resilience?
A:
Resilience is a material's ability to absorb energy when deformed elastically and release that energy upon unloading. It's related to Young's modulus because materials with higher Young's moduli can store more elastic energy per unit volume for a given strain. However, resilience also depends on the yield strength, as it's defined by the area under the stress-strain curve up to the yield point.
Q: How does Young's modulus affect the natural frequency of vibration in structures?
A:
Young's modulus directly influences the natural frequency of vibration in structures. The natural frequency is proportional to the square root of the stiffness-to-mass ratio. Since Young's modulus is a measure of stiffness, structures made from materials with higher Young's moduli will have higher natural frequencies, assuming the same mass and geometry.
Q: What's the significance of Young's modulus in the design of MEMS (Micro-Electro-Mechanical Systems)?
A:
In MEMS design, Young's modulus is crucial because it determines how micro-structures will deform under applied forces. This is particularly important for devices like accelerometers, pressure sensors, and micro-actuators. Understanding Young's modulus at the microscale is essential for predicting device performance and reliability.