Chapter–9 Mechanical Properties of Solids Assertion Reason
These questions of two statements each, printed as Assertion and Reason. While answering these Questions you are required to choose any one of the following four responses.
(A) If both Assertion & Reason are true & the Reason is a correct explanation of the Assertion.
(B) If both Assertion and Reason are true but Reason is not a correct explanation of the Assertion.
(C) If Assertion is true but the Reason is false.
(D) If Assertion & Reason both are false.
Q.1 Assertion : Elastic restoring forces may be conservative.
Reason : The value of strain for same stress are different while increasing the load and while decreasing the load.
(1) A (2) B (3) C (4) D
Answer:2
Q.2 Assertion : Work is required to be done to stretch a wire. This work is stored in the wire in the form of elastic potential energy.
Reason : Work is required to be done against the intermolecular forces of attraction.
(1) A (2) B (3) C (4) D
Answer:1
Q.3 Assertion : The bridges are declared unsafe after a long use.
Reason : Elastic strength of bridges losses with time.
(1) A (2) B (3) C (4) D
Answer:1
Q.4 Assertion : Young’s modulus for a perfectly plastic body is zero.
Reason : For a perfectly plastic body, restoring force is zero.
(1) A (2) B (3) C (4) D
Answer:1
Q.5 Assertion : Identical springs of steel and copper are equally stretched. More work will be done on the steel spring.
Reason : Steel is more elastic than copper.
(1) A (2) B (3) C (4) D
Answer:1
Q.6 Assertion : Stress is the internal force per unit area of a body.
Reason : Rubber is more elastic than steel.
(1) A (2) B (3) C (4) D
Answer:3
Q.7 Assertion : Rubber is more elastic than glass.
Reason : The rubber has higher modulus of elasticity than glass.
(1) A (2) B (3) C (4) D
Answer:4
Assertion-Reason Questions and Answers
Chapter 9: Mechanical Properties of Solids
- Assertion (A): A material with a high Young’s modulus is very stiff.
Reason (R): Young’s modulus is a measure of the stiffness of a material.- (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- (b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
- (c) Assertion (A) is true but Reason (R) is false.
- (d) Assertion (A) is false but Reason (R) is true.
Answer: (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- Assertion (A): The stress-strain curve for a ductile material shows a large plastic region.
Reason (R): Ductile materials can undergo significant plastic deformation before fracture.- (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- (b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
- (c) Assertion (A) is true but Reason (R) is false.
- (d) Assertion (A) is false but Reason (R) is true.
Answer: (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- Assertion (A): The shear modulus of a material is always less than its Young’s modulus.
Reason (R): Shear deformation involves changes in shape without changing volume.- (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- (b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
- (c) Assertion (A) is true but Reason (R) is false.
- (d) Assertion (A) is false but Reason (R) is true.
Answer: (b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
- Assertion (A): A brittle material has a small plastic region in its stress-strain curve.
Reason (R): Brittle materials fracture without significant plastic deformation.- (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- (b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
- (c) Assertion (A) is true but Reason (R) is false.
- (d) Assertion (A) is false but Reason (R) is true.
Answer: (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- Assertion (A): The bulk modulus of a material is a measure of its resistance to compressive stress.
Reason (R): Bulk modulus is defined as the ratio of volumetric stress to the corresponding volumetric strain.- (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- (b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
- (c) Assertion (A) is true but Reason (R) is false.
- (d) Assertion (A) is false but Reason (R) is true.
Answer: (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- Assertion (A): When a material is under tensile stress, its length increases.
Reason (R): Tensile stress produces a force that pulls the material apart.- (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- (b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
- (c) Assertion (A) is true but Reason (R) is false.
- (d) Assertion (A) is false but Reason (R) is true.
Answer: (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- Assertion (A): A material with a low Poisson’s ratio is less likely to deform laterally when compressed longitudinally.
Reason (R): Poisson’s ratio is the ratio of lateral strain to longitudinal strain.- (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- (b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
- (c) Assertion (A) is true but Reason (R) is false.
- (d) Assertion (A) is false but Reason (R) is true.
Answer: (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- Assertion (A): The Young’s modulus of a material is always greater than its shear modulus.
Reason (R): Young’s modulus and shear modulus are measures of different types of deformation.- (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- (b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
- (c) Assertion (A) is true but Reason (R) is false.
- (d) Assertion (A) is false but Reason (R) is true.
Answer: (b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
- Assertion (A): A wire with a larger cross-sectional area can withstand more tensile stress.
Reason (R): Tensile stress is the force applied per unit area of the cross-section.- (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
- (b) Both Assertion (A) and Reason (R) are true but Reason (R) is not the correct explanation of Assertion (A).
- (c) Assertion (A) is true but Reason (R) is false.
- (d) Assertion (A) is false but Reason (R) is true.</li
Chapter–8: Gravitation Assertion Reason
Chapter–10: Mechanical Properties of Fluids Assertion Reason
Assertion-Reason Questions: Chapter 9 – Mechanical Properties of Solids
Assertion: Young’s modulus is a measure of the stiffness of a material.
Reason: Young’s modulus relates stress to strain in a material.
Answer: True. Young’s modulus quantifies the stiffness of a material by relating stress to strain.
Assertion: A ductile material can undergo significant plastic deformation before fracture.
Reason: Ductility is the ability of a material to be drawn into wires.
Answer: True. Ductile materials can undergo extensive plastic deformation before breaking.
Assertion: The area under a stress-strain curve represents the toughness of the material.
Reason: Toughness is the ability of a material to absorb energy up to fracture.
Answer: True. The area under the stress-strain curve indicates the energy absorbed by the material before fracture, hence representing toughness.
Assertion: Elastic limit is the maximum stress a material can withstand without undergoing permanent deformation.
Reason: Beyond the elastic limit, a material exhibits plastic deformation.
Answer: True. Elastic limit is the stress beyond which the material does not return to its original shape, indicating the onset of plastic deformation.
Assertion: Shear modulus is applicable to materials that undergo shearing stress.
Reason: Shear modulus measures a material’s resistance to deformation by shear stress.
Answer: True. Shear modulus specifically applies to materials experiencing shearing forces and measures their resistance to such deformation.
