Free Online MCQs on Mechanical Properties of Solids

MCQs on Mechanical Properties of Solids for JEE Mains

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Time: 02:00

Q1: For a ductile metal specimen, if the applied stress exceeds its yield strength, the specimen undergoes plastic deformation. Which parameter best quantifies the stiffness of the material in the elastic region?

Correct Answer: A) \( \text{Young's modulus} \)

Explanation: Young's modulus is defined as the ratio of tensile stress to tensile strain in the elastic region and directly measures the stiffness of a material in tension or compression.

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Q2: Which property of a solid material measures its resistance to uniform compression?

Correct Answer: A) \( \text{Bulk modulus} \)

Explanation: The bulk modulus is defined as the ratio of the applied pressure to the relative decrease in volume, making it the measure of a material’s resistance to uniform compression.

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Q3: In a tensile test, what does the area under the stress-strain curve up to the elastic limit represent?

Correct Answer: A) \( \text{Strain energy per unit volume} \)

Explanation: The area under the stress-strain curve (up to the elastic limit) represents the elastic strain energy stored per unit volume, which is fully recoverable once the load is removed.

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Q4: A cylindrical rod is subjected to a torsional load. Which property of the material determines its resistance to shear deformation?

Correct Answer: A) \( \text{Shear modulus} \)

Explanation: The shear modulus quantifies a material's resistance to shear deformation; it is defined as the ratio of shear stress to shear strain.

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Q5: What is the significance of the proportional limit in a stress-strain curve?

Correct Answer: A) It is the maximum stress that can be applied without permanent deformation.

Explanation: Up to the proportional limit, stress and strain maintain a linear relationship. This means the deformation is completely elastic and fully recoverable after unloading.

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Q6: Which test is primarily used to determine the ductility of a material?

Correct Answer: A) Tensile test

Explanation: The tensile test provides key data such as elongation and reduction of area, which are indicators of a material’s ductility.

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Q7: What does Poisson's ratio of a material represent?

Correct Answer: A) The ratio of lateral strain to axial strain

Explanation: Poisson's ratio is defined as the negative ratio of transverse (lateral) strain to axial (longitudinal) strain when a material is stretched, reflecting how much it contracts laterally.

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Q8: In bending of beams, which stress is maximum at the outermost fibers of the beam cross-section?

Correct Answer: A) Bending stress

Explanation: During bending, the extreme fibers (furthest from the neutral axis) experience the highest tensile or compressive stresses, known collectively as bending stress.

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Q9: Which parameter is used to determine the energy absorption capability of a material in impact tests?

Correct Answer: A) Toughness

Explanation: Toughness is the measure of the energy a material can absorb before fracturing, reflecting a combination of strength and ductility.

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Q10: During a compression test, the initial linear portion of the stress-strain curve is used to calculate which modulus?

Correct Answer: A) Young's modulus

Explanation: In the elastic region of a compression test, the slope of the stress-strain curve yields Young's modulus, indicating the material's stiffness under compression.

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Q11: When a material exhibits strain hardening, what is the effect on its mechanical properties?

Correct Answer: A) Increase in yield strength

Explanation: Strain hardening increases the yield strength as the dislocation density rises, which makes further plastic deformation more difficult, although it may reduce ductility.

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Q12: Which term describes the ability of a material to absorb energy and plastically deform without fracturing?

Correct Answer: A) Toughness

Explanation: Toughness is the capacity of a material to absorb energy through plastic deformation before fracturing, combining both strength and ductility characteristics.

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Q13: A material with a high yield strength and low ductility is best described as:

Correct Answer: A) Brittle

Explanation: Materials that have a high yield strength but low ductility tend to fracture with little plastic deformation, which is characteristic of brittle materials.

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Q14: In standardized hardness testing, which of the following factors has the least influence on the measured hardness value?

Correct Answer: D) Surface oxidation

Explanation: Standardized hardness tests are designed to minimize the effects of surface conditions such as oxidation, emphasizing intrinsic material properties like chemical composition, heat treatment, and grain structure.

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Q15: What is the significance of the modulus of resilience in materials engineering?

Correct Answer: A) It represents the maximum energy per unit volume that can be elastically stored.

Explanation: The modulus of resilience is defined as the area under the elastic portion of the stress-strain curve, quantifying the maximum energy per unit volume that a material can absorb elastically before yielding.