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

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

Edited By Team Careers360 | Updated on Jul 02, 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

Also read -

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 units	Pa
Imperial Unit	Pis
Dimension	ML^-1T^-2

YOUNG’S MODULUS= STRESS/STRAIN

NEET Highest Scoring Chapters & Topics

This ebook serves as a valuable study guide for NEET exams, specifically designed to assist students in light of recent changes and the removal of certain topics from the NEET exam.

Download E-book

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.

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

Related Topics Link,

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:

Frequently Asked Questions (FAQs)

1. Determine the Young’s modulus of a material with an elastic stress of 4 N/m^2 and a strain of 0.15.

Given:

Stress = 4 N/m2

Strain = 0.15

The Young’s modulus formula is E = σ / ϵ

= 4 / 0.15 =26.66 N/m^2.

2. Give examples of dimensionless quantities.

Poison's ratio, Strain etc

3. What exactly is ductility?

Ductility is the property of a material that allows it to be pulled to a smaller portion when tensile stress is applied.

4. What is dimension of young modulus?

[ML^-1T^-2] is the dimensional formula for Young’s modulus.

5. What factors influence Young’s modulus?

The Young’s modulus of a substance is an unchangeable fundamental feature of all materials. Temperature and pressure, however, play a role. The Young’s modulus (or Elastic Modulus) is a measure of a material's stiffness. To put it another way, it refers to how easily it may be bent or stretched.

6. What is the significance of elastic modulus?

A material's Young’s modulus is a useful property to know in order to forecast how it will behave when subjected to a force. This is critical for practically everything in our environment, including buildings, bridges, automobiles, and more.

7. What is Young's modulus and why is it important?

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.

8. How is Young's modulus different from other elastic moduli?

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.

9. Can Young's modulus be negative?

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.

10. Why do some materials have a higher Young's modulus than others?

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.

11. How is Young's modulus related to Hooke's Law?

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.

12. How does temperature affect Young's modulus?

Generally, as temperature increases, Young's modulus decreases for most materials. This is because higher temperatures increase atomic vibrations, weakening the interatomic bonds and making the material more easily deformable. However, there are some exceptions to this rule, particularly in certain polymers and composites.

13. What's the difference between Young's modulus and tensile strength?

Young's modulus measures a material's stiffness in the elastic region, where deformation is reversible. Tensile strength, on the other hand, measures the maximum stress a material can withstand before failing. A material can have high Young's modulus (very stiff) but low tensile strength (breaks easily), or vice versa.

14. Why is the unit of Young's modulus the same as that of pressure?

Young's modulus is defined as the ratio of stress to strain. Stress has units of force per unit area (like pressure), while strain is dimensionless (a ratio of lengths). Therefore, the units of Young's modulus end up being the same as those of stress or pressure, typically Pascal (Pa) or N/m².

15. How is Young's modulus measured experimentally?

Young's modulus is typically measured through tensile testing. A sample of the material is subjected to a known tensile force, and the resulting elongation is measured. By plotting stress against strain, Young's modulus can be determined from the slope of the linear portion of the graph in the elastic region.

16. How does Young's modulus relate to a material's ductility?

While Young's modulus doesn't directly measure ductility, it can provide some insights. Materials with lower Young's moduli tend to be more ductile, as they deform more easily under stress. However, ductility also depends on other factors like the material's yield strength and ultimate tensile strength.

17. Can composite materials have a Young's modulus higher than their individual components?

Yes, it's possible for composite materials to have a Young's modulus higher than any of their individual components. This is one of the advantages of composites - by combining materials strategically, we can create a composite with superior properties. For example, carbon fiber reinforced polymers can have a higher Young's modulus than either carbon fibers or polymers alone.

18. How does Young's modulus influence the deflection of beams?

Young's modulus plays a crucial role in beam deflection. For a given load and beam geometry, a material with a higher Young's modulus will deflect less. This is why materials with high Young's moduli, like steel, are often used in construction where minimal deflection is desired.

19. How does crystal structure affect Young's modulus?

Crystal structure significantly influences Young's modulus. Materials with more closely packed atoms and stronger interatomic bonds generally have higher Young's moduli. For example, diamond has an extremely high Young's modulus due to its tight, tetrahedral crystal structure with strong covalent bonds.

20. What's the difference between engineering stress-strain and true stress-strain in relation to Young's modulus?

Engineering stress-strain uses the original cross-sectional area and length of the sample, while true stress-strain accounts for the changing dimensions during deformation. Young's modulus is typically calculated using engineering stress-strain, as it's easier to measure. However, for large deformations, true stress-strain provides a more accurate representation of material behavior.

21. How does Young's modulus relate to a material's fracture toughness?

While Young's modulus and fracture toughness are distinct properties, they are related. Materials with higher Young's moduli tend to be more brittle and have lower fracture toughness. This is because stiffer materials often have less ability to deform plastically and absorb energy before fracturing. However, this relationship is not absolute, and other factors also influence fracture toughness.

22. How does Young's modulus relate to a material's Poisson's ratio?

Young's modulus and Poisson's ratio are both elastic constants that describe a material's behavior under stress. While they measure different aspects of deformation, they are related through other elastic constants. For isotropic materials, knowing Young's modulus and Poisson's ratio allows calculation of other elastic properties like shear modulus and bulk modulus.

23. Can Young's modulus be used to predict material failure?

While Young's modulus alone cannot predict material failure, it's an important parameter in understanding a material's behavior. Young's modulus describes the material's behavior in the elastic region, before permanent deformation or failure occurs. To predict failure, additional properties like yield strength, ultimate tensile strength, and fracture toughness must be considered.

24. How does porosity affect a material's Young's modulus?

Increased porosity generally decreases a material's Young's modulus. This is because pores reduce the effective cross-sectional area that can bear load, making the material more compliant. The relationship between porosity and Young's modulus is often described by empirical models, such as the Gibson-Ashby model for cellular solids.

25. What's the significance of the yield point in relation to Young's modulus?

The yield point marks the transition from elastic to plastic deformation. Young's modulus describes the material's behavior before this point, in the elastic region. Beyond the yield point, the stress-strain relationship becomes non-linear, and the material no longer returns to its original shape when the stress is removed. Understanding both Young's modulus and the yield point is crucial for predicting material behavior under load.

26. Why is Young's modulus important in the study of nanomaterials?

In nanomaterials, Young's modulus becomes particularly important because material properties can change dramatically at the nanoscale. Understanding how Young's modulus varies with size and structure at the nanoscale is crucial for designing nanodevices and nanocomposites. Additionally, techniques for measuring Young's modulus at the nanoscale, such as nanoindentation, have become important areas of research.

27. How does work hardening affect Young's modulus?

Work hardening, or strain hardening, primarily affects a material's yield strength and ultimate tensile strength, not its Young's modulus. Young's modulus is a property of the material in its elastic region, before plastic deformation occurs. Work hardening takes place in the plastic region, beyond the yield point. However, severe plastic deformation can introduce residual stresses and microstructural changes that might slightly alter the apparent Young's modulus in subsequent loading.

28. What's the relationship between Young's modulus and flexural modulus?

For isotropic materials, Young's modulus and flexural modulus are theoretically identical. Both describe a material's stiffness, but they're measured differently. Young's modulus is typically measured in tension or compression, while flexural modulus is measured in bending. In practice, flexural modulus can be slightly lower than Young's modulus due to shear deformation in bending tests.

29. How does Young's modulus relate to a material's hardness?

While Young's modulus and hardness are distinct properties, they are often correlated. Materials with higher Young's moduli tend to be harder, as both properties relate to the strength of interatomic bonds. However, this correlation is not perfect, and there are exceptions. Hardness also depends on other factors like crystal structure and the material's ability to plastically deform.

30. Can Young's modulus be used to estimate a material's melting point?

While there's no direct relationship between Young's modulus and melting point, both properties are influenced by the strength of interatomic bonds. Materials with higher Young's moduli often have higher melting points, but this correlation is not universal and should not be used for precise predictions. Other factors, like crystal structure and atomic mass, also significantly influence melting point.

31. How does Young's modulus relate to a material's thermal expansion coefficient?

While Young's modulus and thermal expansion coefficient are distinct properties, they are often inversely related. Materials with higher Young's moduli typically have lower thermal expansion coefficients. This is because stronger interatomic bonds (which lead to higher Young's moduli) also tend to restrict thermal expansion. However, this relationship is not universal and there are exceptions.

32. How does Young's modulus affect the speed of crack propagation in materials?

Young's modulus influences crack propagation speed indirectly. Materials with higher Young's moduli tend to have higher crack propagation speeds because they store more elastic energy, which can be released to drive crack growth. However, crack propagation also depends on other factors like fracture toughness and plastic deformation at the crack tip.

33. What's the relationship between Young's modulus and a material's acoustic properties?

Young's modulus significantly influences a material's acoustic properties. As mentioned earlier, the speed of sound in a material is proportional to the square root of Young's modulus divided by density. Additionally, materials with higher Young's moduli tend to have higher acoustic impedance, which affects how sound waves are transmitted and reflected at interfaces.

34. How does Young's modulus relate to a material's creep behavior?

While Young's modulus describes a material's instantaneous elastic response, creep involves time-dependent deformation under constant stress. Materials with higher Young's moduli generally exhibit less creep, as they're more resistant to deformation. However, creep behavior also depends on other factors like temperature, stress level, and microstructure.

35. Can Young's modulus be used to predict a material's fatigue life?

Young's modulus alone cannot predict fatigue life, but it's an important factor. Materials with higher Young's moduli tend to have better fatigue resistance because they deform less under cyclic loading. However, fatigue life also depends critically on factors like stress amplitude, mean stress, surface condition, and microstructure.

36. How does grain size affect Young's modulus in polycrystalline materials?

In polycrystalline materials, grain size typically has a minor effect on Young's modulus. While grain boundaries can slightly reduce the overall stiffness, this effect is usually small for bulk materials. However, in nanocrystalline materials with extremely small grain sizes, the high volume fraction of grain boundaries can lead to a more noticeable reduction in Young's modulus.

37. How does Young's modulus relate to a material's wear resistance?

While wear resistance depends on multiple factors, Young

38. Can Young's modulus change for a given material?

While Young's modulus is generally considered a material property, it can change under certain conditions. Factors such as temperature, crystal structure, and manufacturing processes can affect a material's Young's modulus. Additionally, some materials exhibit anisotropy, meaning their Young's modulus varies depending on the direction of applied force.

39. What's the significance of the stress-strain curve in understanding Young's modulus?

The stress-strain curve provides a visual representation of a material's behavior under load. Young's modulus is represented by the slope of the linear portion of this curve in the elastic region. This initial linear region indicates where the material obeys Hooke's Law, and its slope gives us the value of Young's modulus.

40. How does Young's modulus affect the speed of sound in a material?

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.

41. Why is Young's modulus important in the design of springs?

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.

42. How does the concept of Young's modulus apply to biological materials?

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.

43. What's the relationship between Young's modulus and a material's ability to store elastic energy?

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.

44. Can liquids have a Young's modulus?

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.

45. Why do some materials, like rubber, seem to violate Hooke's Law?

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.

46. How does Young's modulus relate to a material's resilience?

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.

47. How does Young's modulus affect the natural frequency of vibration in structures?

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.

48. What's the significance of Young's modulus in the design of MEMS (Micro-Electro-Mechanical Systems)?

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.

49. Can Young's modulus be negative for metamaterials?

While conventional materials cannot have a negative Young's modulus, certain engineered metamaterials can exhibit apparent negative stiffness under specific conditions. These materials are designed to have unusual mechanical properties that arise from their structure rather than their composition. However, it's important to note that these are effective properties of the structure, not intrinsic material properties.

50. What's the significance of Young's modulus in the study of biomechanics?

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.