1. What is elastic behavior in solids?
Answer: Elastic behavior in solids refers to the property of a material to return to its original shape and size after the removal of an applied force.
2. Describe the stress-strain relationship.
Answer: The stress-strain relationship describes how a material deforms under stress, with stress being the force applied per unit area and strain being the deformation produced. It typically shows a linear relationship within the elastic limit.
3. State Hooke’s Law.
Answer: Hooke’s Law states that, within the elastic limit, the strain in a material is directly proportional to the applied stress. Mathematically, it is expressed as
where σ is stress, ϵ is strain, and E is Young’s modulus.
4. What is Young’s modulus?
Answer: Young’s modulus is a measure of the stiffness of a solid material. It is defined as the ratio of tensile stress to tensile strain.
5. Define bulk modulus.
Answer: The bulk modulus is a measure of a material’s resistance to uniform compression. It is defined as the ratio of an infinitesimal pressure increase to the resulting relative decrease in volume.
6. Explain the modulus of rigidity.
Answer: The modulus of rigidity, also known as shear modulus, is a measure of a material’s ability to withstand shear stress. It is defined as the ratio of shear stress to shear strain.
7. What is the pressure due to a fluid column?
Answer: The pressure due to a fluid column is given by the equation
where h is the height of the fluid column, ρ is the density of the fluid, and g is the acceleration due to gravity.
8. State Pascal’s law and its applications.
Answer: Pascal’s law states that in a confined fluid, a change in pressure is transmitted equally in all directions. Applications include hydraulic presses and brake systems.
9. Describe the effect of gravity on fluid pressure.
Answer: Gravity causes a pressure gradient in a fluid, with pressure increasing with depth due to the weight of the fluid above.
10. What is viscosity?
Answer: Viscosity is a measure of a fluid’s resistance to flow or deformation. It describes the internal friction within the fluid.
11. State Stokes’ law.
Answer: Stokes’ law states that the force of viscosity on a small sphere moving through a viscous fluid is directly proportional to the radius of the sphere, the fluid’s viscosity, and the velocity of the sphere. Mathematically,
12. What is terminal velocity?
Answer: Terminal velocity is the constant speed that a freely falling object eventually reaches when the resistance of the medium prevents further acceleration.
13. Differentiate between streamline and turbulent flow.
Answer: Streamline (laminar) flow occurs when fluid flows in parallel layers with no disruption between them, while turbulent flow is characterized by chaotic changes in pressure and flow velocity.
14. What is critical velocity in fluid dynamics?
Answer: Critical velocity is the maximum velocity at which a fluid can flow through a pipe without becoming turbulent.
15. State Bernoulli’s principle and its applications.
Answer: Bernoulli’s principle states that in a flowing fluid, an increase in velocity occurs simultaneously with a decrease in pressure or potential energy. Applications include airplane wings, Venturi meters, and carburetors.
16. What is surface energy and surface tension?
Answer: Surface energy is the energy required to increase the surface area of a liquid due to intermolecular forces. Surface tension is the elastic tendency of a fluid surface which makes it acquire the least surface area possible.
17. Define angle of contact.
Answer: The angle of contact is the angle formed between the tangent to the liquid surface and the solid surface at the point of contact.
18. Explain excess pressure across a curved surface.
Answer: Excess pressure across a curved surface is the difference in pressure between the inside and outside of a curved surface, such as a bubble or drop. It is given by
for a drop or bubble of radius r, where γ is the surface tension.
19. Describe the application of surface tension in drops, bubbles, and capillary rise.
Answer: Surface tension causes droplets to form spherical shapes, bubbles to have a spherical outer layer, and allows liquids to rise or fall in capillary tubes depending on the adhesive and cohesive forces.
20. What are the modes of heat transfer?
Answer: The modes of heat transfer are conduction (transfer through a solid material), convection (transfer through fluid motion), and radiation (transfer through electromagnetic waves).
21. Explain thermal expansion and its types.
Answer: Thermal expansion is the increase in the size of a material as its temperature increases. The types are linear expansion (change in one dimension), area expansion (change in two dimensions), and volumetric expansion (change in three dimensions).
22. Define specific heat capacity.
Answer: Specific heat capacity is the amount of heat required to raise the temperature of one kilogram of a substance by one degree Celsius.
23. What is calorimetry?
Answer: Calorimetry is the measurement of the amount of heat released or absorbed during a chemical reaction, physical change, or heat capacity measurement.
24. Explain the concept of latent heat.
Answer: Latent heat is the heat required to change the state of a substance without changing its temperature. It includes latent heat of fusion (solid to liquid) and latent heat of vaporization (liquid to gas).
25. Describe conduction in heat transfer.
Answer: Conduction is the transfer of heat through a material without the movement of the material itself, typically occurring in solids through lattice vibrations and free electron movement.
26. What is convection in heat transfer?
Answer: Convection is the transfer of heat by the physical movement of a fluid (liquid or gas) caused by temperature differences within the fluid.
27. Explain radiation in heat transfer.
Answer: Radiation is the transfer of heat through electromagnetic waves without the need for a medium. It can occur in a vacuum, such as the heat from the sun reaching the earth.
28. What is terminal velocity and how is it determined?
Answer: Terminal velocity is the steady speed achieved by an object freely falling through a fluid when the forces of gravity and drag are equal and opposite. It is determined by factors like the object’s size, shape, and the fluid’s viscosity.
29. What are streamline and turbulent flows?
Answer: Streamline flow is smooth and orderly, where fluid particles move in parallel layers. Turbulent flow is chaotic, with fluid particles moving in irregular paths, leading to eddies and vortices.
30. Discuss the applications of Bernoulli’s principle.
Answer: Applications of Bernoulli’s principle include aircraft wing design for lift, carburetors in engines, and Venturi meters for measuring fluid flow rates.