Free Deformation and Elasticity MCQs with Answers

1. A body which breaks down just after crossing the elastic limit is known as:

• A. Elastic
• B. Hard
• C. Ductile
• D. Brittle

Explanation: A body that breaks down immediately after crossing the elastic limit is known as brittle.

2. The given diagram shows a helical spring attached to a fixed surface. The value of spring constant is taken as 'k' 300 N/m and a 100 N weight is attached at the bottom.The extension in the spring will be

• A. 0.333 m
• B. 0.666 m
• C. 3 m
• D. 6 m

Explanation: The correct answer is 0.333 m. When a weight is attached to the spring, it exerts a force on the spring, causing it to extend. By applying Hooke's Law (F = kx), where F is the force, k is the spring constant, and x is the extension, we can calculate the extension in the spring to be 0.333 meters. Options B, C, and D are incorrect because they do not account for the force exerted by the weight of the object, leading to incorrect extension calculations.

3. The ratio between applied stress to the volumetric strain is called

• A. Bulk modulus.
• B. Shear modulus.
• C. Young's modulus.
• D. Modulus of plasticity.

Explanation: The correct concept for the ratio between applied stress and volumetric strain is the bulk modulus. However, the given correct option 'Young's modulus' is incorrect for the provided question. Young's modulus is specifically the ratio of stress to strain in the linear elasticity regime of a uniaxial deformation. The bulk modulus is indeed the correct term for volumetric stress-strain relationships. Therefore, the question seems to be incorrectly keyed.The other options are incorrect as follows:Shear modulus: Involves shear stress and shear strain, not volumetric strain.Modulus of plasticity: Is not a recognized term in standard material science terminology.Young's modulus: Refers to tensile stress and tensile strain, not volumetric changes.

4. A piece of copper is drawn into continuous wire. What behavior is the copper exhibiting?

• A. Brittle only
• B. Elastic only
• C. Plastic Only
• D. Both brittle and elastic

Explanation: For stresses beyond the elastic limit, a material exhibits plastic behaviour. This means the material deforms irreversibly and does not return to its original shape and size, even when the load is removed.

5. The force applied on unit area to produce any change in the volume or length of a body is called:

• A. Strain
• B. Stress
• C. Elasticity
• D. Equilibrium

Explanation: When the force applied produces a change in length or volume of the object then is it called stress, otherwise the term strain is used.