Mcq on mechanical properties of solids with answers
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1. What is the property of a material that allows it to regain its original shape after the removal of deforming force?
A. Elasticity
B. Plasticity
C. Rigidity
D. Flexibility
The correct answer is A. Elasticity.
Explanation:
Elasticity refers to the ability of a material to return to its original shape after the deforming force is removed.
Explanation:
Elasticity refers to the ability of a material to return to its original shape after the deforming force is removed.
2. What is the SI unit of stress?
A. Joule
B. Newton
C. Pascal
D. Watt
The correct answer is C. Pascal.
Explanation:
Stress is defined as force per unit area, and its SI unit is the pascal (Pa), equivalent to N/m².
Explanation:
Stress is defined as force per unit area, and its SI unit is the pascal (Pa), equivalent to N/m².
3. Which property describes materials that get permanently deformed when force is applied?
A. Elasticity
B. Plasticity
C. Flexibility
D. Rigidity
The correct answer is B. Plasticity.
Explanation:
Plasticity is the property of materials that leads to permanent deformation when subjected to a force.
Explanation:
Plasticity is the property of materials that leads to permanent deformation when subjected to a force.
4. The ratio of change in length to the original length of a body is known as:
A. Shearing strain
B. Longitudinal strain
C. Volume strain
D. Tensile strain
The correct answer is B. Longitudinal strain.
Explanation:
Longitudinal strain is the ratio of change in length to the original length caused by tensile or compressive stress.
Explanation:
Longitudinal strain is the ratio of change in length to the original length caused by tensile or compressive stress.
5. What type of stress occurs when a solid is subjected to a force that acts parallel to its surface?
A. Longitudinal stress
B. Shearing stress
C. Compressive stress
D. Tensile stress
The correct answer is B. Shearing stress.
Explanation:
Shearing stress arises when a tangential force is applied, causing relative displacement of the material layers.
Explanation:
Shearing stress arises when a tangential force is applied, causing relative displacement of the material layers.
6. What is the dimensional formula of stress?
A. [M¹L⁰T⁻²]
B. [M¹L⁻¹T⁻²]
C. [M¹L⁻³T⁻²]
D. [M¹L¹T⁻²]
The correct answer is B. [M¹L⁻¹T⁻²].
Explanation:
Stress has the dimensional formula of force (MLT⁻²) divided by area (L²), resulting in [M¹L⁻¹T⁻²].
Explanation:
Stress has the dimensional formula of force (MLT⁻²) divided by area (L²), resulting in [M¹L⁻¹T⁻²].
7. Stress is defined as:
A. Force applied per unit length
B. Force applied per unit area
C. Force applied per unit volume
D. Force applied per unit mass
The correct answer is B. Force applied per unit area.
Explanation:
Stress is the restoring force per unit area developed in a body when it is subjected to a deforming force.
Explanation:
Stress is the restoring force per unit area developed in a body when it is subjected to a deforming force.
8. Longitudinal strain is given by:
A. ∆V/V
B. ∆L/L
C. ∆x/L
D. tanθ
The correct answer is B. ∆L/L.
Explanation:
Longitudinal strain is defined as the ratio of the change in length (∆L) to the original length (L).
Explanation:
Longitudinal strain is defined as the ratio of the change in length (∆L) to the original length (L).
9. Hydraulic stress is applied in which direction?
A. Parallel to the surface
B. Perpendicular to the surface
C. At an angle of 45°
D. Randomly
The correct answer is B. Perpendicular to the surface.
Explanation:
Hydraulic stress acts perpendicular to the surface, compressing the body uniformly from all directions.
Explanation:
Hydraulic stress acts perpendicular to the surface, compressing the body uniformly from all directions.
10. The Young's modulus of a material is defined as the ratio of:
A. Stress to strain
B. Strain to stress
C. Longitudinal stress to longitudinal strain
D. Volume stress to volume strain
The correct answer is C. Longitudinal stress to longitudinal strain.
Explanation:
Young's modulus measures the elasticity of a material by taking the ratio of longitudinal stress to longitudinal strain.
Explanation:
Young's modulus measures the elasticity of a material by taking the ratio of longitudinal stress to longitudinal strain.
11. The SI unit of Young's modulus is:
A. Joule
B. Newton
C. Pascal
D. Watt
The correct answer is C. Pascal.
Explanation:
Young's modulus is expressed in pascals (Pa), which is equivalent to newtons per square meter (N/m²).
Explanation:
Young's modulus is expressed in pascals (Pa), which is equivalent to newtons per square meter (N/m²).
12. Poisson's ratio is defined as the ratio of:
A. Longitudinal strain to lateral strain
B. Lateral strain to longitudinal strain
C. Stress to strain
D. Strain to stress
The correct answer is B. Lateral strain to longitudinal strain.
Explanation:
Poisson's ratio describes the negative ratio of lateral strain to longitudinal strain in a stretched material.
Explanation:
Poisson's ratio describes the negative ratio of lateral strain to longitudinal strain in a stretched material.
13. The elastic limit is:
A. The maximum stress a material can withstand without permanent deformation
B. The point at which stress is minimum
C. The point at which strain is maximum
D. The ratio of stress to strain
The correct answer is A. The maximum stress a material can withstand without permanent deformation.
Explanation:
Beyond the elastic limit, the material undergoes plastic deformation and does not return to its original shape.
Explanation:
Beyond the elastic limit, the material undergoes plastic deformation and does not return to its original shape.
14. Bulk modulus is related to:
A. Longitudinal stress
B. Volume stress
C. Shear stress
D. Tensile stress
The correct answer is B. Volume stress.
Explanation:
Bulk modulus is the ratio of volume stress to volume strain, indicating a material's resistance to uniform compression.
Explanation:
Bulk modulus is the ratio of volume stress to volume strain, indicating a material's resistance to uniform compression.
15. Shear modulus is defined for:
A. Tensile stress
B. Volume stress
C. Shearing stress
D. Longitudinal stress
The correct answer is C. Shearing stress.
Explanation:
Shear modulus measures the ratio of shearing stress to shearing strain in a material.
Explanation:
Shear modulus measures the ratio of shearing stress to shearing strain in a material.
16. Which of the following materials has the highest elasticity?
A. Rubber
B. Plastic
C. Steel
D. Copper
The correct answer is C. Steel.
Explanation:
Steel has the highest elasticity among common materials due to its large Young's modulus value, making it resistant to deformation.
Explanation:
Steel has the highest elasticity among common materials due to its large Young's modulus value, making it resistant to deformation.
17. What is Hooke's Law? Provide its mathematical expression.
A. Stress is inversely proportional to strain.
B. Stress and strain are unrelated.
C. Stress is directly proportional to strain for small deformations.
D. Stress equals strain squared.
The correct answer is C. Stress is directly proportional to strain for small deformations.
Explanation:
Hooke's Law states that within the elastic limit of a material, stress is proportional to strain. This is represented as stress = k × strain.
Explanation:
Hooke's Law states that within the elastic limit of a material, stress is proportional to strain. This is represented as stress = k × strain.
18. What is the proportionality constant in Hooke's Law called?
A. Modulus of elasticity
B. Yield point
C. Ultimate tensile strength
D. Shear modulus
The correct answer is A. Modulus of elasticity.
Explanation:
The proportionality constant k in Hooke's Law is referred to as the modulus of elasticity, which measures a material's resistance to deformation.
Explanation:
The proportionality constant k in Hooke's Law is referred to as the modulus of elasticity, which measures a material's resistance to deformation.
19. In which region of the stress-strain curve is Hooke's law valid?
A. Region O to A
B. Region A to B
C. Region B to D
D. Region D to E
The correct answer is A. Region O to A.
Explanation:
Hooke's law is valid in the linear portion of the stress-strain curve, where stress and strain are directly proportional.
Explanation:
Hooke's law is valid in the linear portion of the stress-strain curve, where stress and strain are directly proportional.
20. What happens when stress exceeds the yield strength of a material?
A. The material behaves elastically.
B. The material undergoes plastic deformation.
C. The material regains its original dimensions.
D. The material fractures immediately.
The correct answer is B. The material undergoes plastic deformation.
Explanation:
When stress exceeds the yield strength, the material enters the plastic deformation region, leading to permanent changes in shape.
Explanation:
When stress exceeds the yield strength, the material enters the plastic deformation region, leading to permanent changes in shape.
21. What is the point on the stress-strain curve where the material shows permanent deformation called?
A. Yield point
B. Ultimate tensile strength
C. Elastic limit
D. Fracture point
The correct answer is A. Yield point.
Explanation:
The yield point marks the limit of elastic behavior, beyond which permanent deformation occurs in the material.
Explanation:
The yield point marks the limit of elastic behavior, beyond which permanent deformation occurs in the material.
22. Which materials are known as elastomers?
A. Materials that exhibit a well-defined plastic region.
B. Materials that show a large elastic region and do not obey Hooke's law.
C. Brittle materials.
D. Ductile materials.
The correct answer is B. Materials that show a large elastic region and do not obey Hooke's law.
Explanation:
Elastomers like rubber and aorta tissue exhibit a large elastic region but may not follow Hooke’s law across the entire range of strain.
Explanation:
Elastomers like rubber and aorta tissue exhibit a large elastic region but may not follow Hooke’s law across the entire range of strain.
23. Which modulus measures the ratio of stress to strain in the longitudinal direction?
A. Shear modulus
B. Modulus of rigidity
C. Young’s modulus
D. Bulk modulus
The correct answer is C. Young’s modulus.
Explanation:
Young’s modulus quantifies the elasticity of a material in the longitudinal direction when subjected to tensile or compressive stress.
Explanation:
Young’s modulus quantifies the elasticity of a material in the longitudinal direction when subjected to tensile or compressive stress.
24. Which type of strain occurs when a body is subjected to a change in shape without a change in volume?
A. Volumetric strain
B. Longitudinal strain
C. Shear strain
D. Elastic strain
The correct answer is C. Shear strain.
Explanation:
Shear strain is defined as the change in shape of a material without any change in volume when a tangential force is applied.
Explanation:
Shear strain is defined as the change in shape of a material without any change in volume when a tangential force is applied.
25. What is the primary reason behind the shear component in mountain formation?
A. The weight of the overlying rocks acting horizontally due to gravity.
B. The lateral movement of tectonic plates.
C. The pressure from the Earth's interior pushing upwards.
D. The expansion of volcanic material beneath the mountain.
The correct answer is A. The weight of the overlying rocks acting horizontally due to gravity.
Explanation:
The shear component in mountain formation is primarily due to the horizontal force exerted by the weight of the overlying rocks acting under their own weight.
Explanation:
The shear component in mountain formation is primarily due to the horizontal force exerted by the weight of the overlying rocks acting under their own weight.
26. Which modulus of elasticity is used to measure the change in volume of a material under pressure?
A. Young’s modulus
B. Shear modulus
C. Bulk modulus
D. Rigidity modulus
The correct answer is C. Bulk modulus.
Explanation:
The bulk modulus is used to quantify a material's resistance to uniform compression and measures the change in volume under pressure.
Explanation:
The bulk modulus is used to quantify a material's resistance to uniform compression and measures the change in volume under pressure.
27. Which of the following conditions define a perfectly elastic body?
A. The body regains its original shape completely after deformation.
B. The body does not deform under stress.
C. The body permanently deforms under stress.
D. The body fractures immediately under stress.
The correct answer is A. The body regains its original shape completely after deformation.
Explanation:
A perfectly elastic body returns to its original shape and size completely upon the removal of external forces, within the elastic limit.
Explanation:
A perfectly elastic body returns to its original shape and size completely upon the removal of external forces, within the elastic limit.
28. Which material is most suitable for constructing a spring?
A. Plastic
B. Steel
C. Rubber
D. Aluminum
The correct answer is B. Steel.
Explanation:
Steel is most suitable for springs due to its high elasticity and strength, allowing it to store and release energy efficiently.
Explanation:
Steel is most suitable for springs due to its high elasticity and strength, allowing it to store and release energy efficiently.
29. Which of the following materials exhibits the least plastic deformation?
A. Rubber
B. Copper
C. Glass
D. Aluminum
The correct answer is C. Glass.
Explanation:
Glass is a brittle material that exhibits very little plastic deformation before breaking.
Explanation:
Glass is a brittle material that exhibits very little plastic deformation before breaking.
30. What does the term "elastic limit" refer to in material science?
A. The maximum stress a material can withstand without permanent deformation.
B. The point at which a material fractures.
C. The stress required to break a material.
D. The stress required to initiate motion.
The correct answer is A. The maximum stress a material can withstand without permanent deformation.
Explanation:
The elastic limit is the maximum stress that a material can endure and still return to its original dimensions after the stress is removed.
Explanation:
The elastic limit is the maximum stress that a material can endure and still return to its original dimensions after the stress is removed.
31. The shearing stress required for rocks to flow is:
A. Constant throughout the rock's volume
B. Independent of the rock's density
C. Dependent on the rock's height and material density
D. Not affected by external factors
The correct answer is C. Dependent on the rock's height and material density.
Explanation:
Shearing stress to rocks to flow is dependent on the height (pressure due to the weight of overlying rocks) and the material density, which influences the force per unit area required.
Explanation:
Shearing stress to rocks to flow is dependent on the height (pressure due to the weight of overlying rocks) and the material density, which influences the force per unit area required.
32. What is the force per unit area at the bottom of a mountain with height \(h\)?
A. \(h \rho g\)
B. \(h \rho g\)
C. \(h \cdot \frac{\rho g}{2}\)
D. \(h \cdot \frac{g}{\rho}\)
The correct answer is B. \(h \rho g\).
Explanation:
The force per unit area at the bottom of the mountain due to its weight is given by \(h \rho g\), where \(\rho\) is the density of the material and \(g\) is the acceleration due to gravity.
Explanation:
The force per unit area at the bottom of the mountain due to its weight is given by \(h \rho g\), where \(\rho\) is the density of the material and \(g\) is the acceleration due to gravity.
33. Why is the stress at the bottom of a mountain not a case of pressure or bulk compression?
A. Because the sides of the mountain are free, making it a shear component.
B. Because the material at the bottom is completely compressed
C. It involves only vertical stress and not lateral stress
D. It is affected by external factors
The correct answer is A. Because the sides of the mountain are free, making it a shear component.
Explanation:
The stress at the bottom of a mountain is due to the weight of the material above, resulting in a shear component rather than bulk compression because the sides are free and not subject to lateral forces.
Explanation:
The stress at the bottom of a mountain is due to the weight of the material above, resulting in a shear component rather than bulk compression because the sides are free and not subject to lateral forces.
34. What is the elastic limit for a typical rock?
A. \(30 \times 10^7 \, \text{N m}^{-2}\)
B. \(3 \times 10^7 \, \text{N m}^{-2}\)
C. \(30 \times 10^6 \, \text{N m}^{-2}\)
D. \(3 \times 10^6 \, \text{N m}^{-2}\)
The correct answer is A. \(30 \times 10^7 \, \text{N m}^{-2}\).
Explanation:
The elastic limit for a typical rock is \(30 \times 10^7 \, \text{N m}^{-2}\), which is the maximum stress the rock can withstand without permanent deformation.
Explanation:
The elastic limit for a typical rock is \(30 \times 10^7 \, \text{N m}^{-2}\), which is the maximum stress the rock can withstand without permanent deformation.
35. How is the height \(h\) of the mountain calculated using the given elastic limit and density?
A. Using the formula \(h = \frac{\text{Elastic limit}}{\rho g}\)
B. Using the formula \(h = \rho g / \text{Elastic limit}\)
C. Using the formula \(h = \text{Elastic limit} \times \rho g\)
D. Using the formula \(h = \rho / \text{Elastic limit} \times g\)
The correct answer is A. Using the formula \(h = \frac{\text{Elastic limit}}{\rho g}\).
Explanation:
The height \(h\) can be calculated by equating the shearing stress (\(h \rho g\)) with the elastic limit and rearranging the formula.
Explanation:
The height \(h\) can be calculated by equating the shearing stress (\(h \rho g\)) with the elastic limit and rearranging the formula.
36. What happens to the shear stress at the base of a mountain when the height increases?
A. It increases linearly with height.
B. It decreases exponentially with height.
C. It remains constant regardless of height.
D. It becomes zero at a certain height.
The correct answer is A. It increases linearly with height.
Explanation:
As the height of the mountain increases, the weight acting on the base (due to gravity) also increases, leading to a linear increase in shear stress.
Explanation:
As the height of the mountain increases, the weight acting on the base (due to gravity) also increases, leading to a linear increase in shear stress.
37. How does the height \(h\) of the mountain relate to the height of Mt. Everest?
A. The calculated height is more than the height of Mt. Everest
B. The calculated height is less than the height of Mt. Everest
C. The height of the mountain is equal to Mt. Everest
D. The calculated height is the height of Mt. Everest minus 5 km
The correct answer is A. The calculated height is more than the height of Mt. Everest.
Explanation:
The calculated height from the equation is 10 km, which is greater than the height of Mt. Everest (8.8 km).
Explanation:
The calculated height from the equation is 10 km, which is greater than the height of Mt. Everest (8.8 km).
38. What does the term "shear component" refer to in the context of a mountain's stability?
A. The component of stress due to weight that acts parallel to the mountain’s surface
B. The force that makes the mountain expand vertically
C. The stress component that affects the mountain’s base only
D. The component that affects only the upper slopes of the mountain
The correct answer is A. The component of stress due to weight that acts parallel to the mountain’s surface.
Explanation:
The shear component refers to the stress that acts parallel to the mountain’s surface, resulting from the weight of overlying material.
Explanation:
The shear component refers to the stress that acts parallel to the mountain’s surface, resulting from the weight of overlying material.
39. What is the impact of the shear component on the stability of a mountain?
A. It contributes to the deformation and potential sliding of the rock masses
B. It reinforces the mountain’s structure
C. It makes the mountain more stable
D. It has no impact on the mountain’s stability
The correct answer is A. It contributes to the deformation and potential sliding of the rock masses.
Explanation:
The shear component results from the weight of overlying material and can lead to deformation and potential sliding of rock masses, impacting the stability of the mountain.
Explanation:
The shear component results from the weight of overlying material and can lead to deformation and potential sliding of rock masses, impacting the stability of the mountain.
40. Why is it important to consider the elastic limit of rocks when studying mountain formation?
A. Because it determines the stress at which the rocks will flow
B. To understand the density of the rock material
C. It helps in calculating the shear stress required for rocks to flow
D. To determine the gravitational pull on the mountain
The correct answer is A. Because it determines the stress at which the rocks will flow.
Explanation:
The elastic limit indicates the maximum stress the rocks can withstand before deformation, which is crucial when studying their behavior under the weight of a mountain.
Explanation:
The elastic limit indicates the maximum stress the rocks can withstand before deformation, which is crucial when studying their behavior under the weight of a mountain.
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