NEET UG - Viscosity, Stokes law, terminal velocity, streamline and turbulent flow, critical velocity One Line Questions & Answers

1. One Poise is equal to how many Pascal-seconds? — 0.1

2. If the radius of a sphere is doubled, its terminal velocity in a given viscous fluid will increase by a factor of: — 4

3. Stokes' Law is derived based on the assumption that the object is: — Spherical and moving slowly

4. In streamline flow, the velocity of any fluid particle is: — Constant at any given point in space

5. Streamline flow is characterized by: — Smooth, orderly fluid motion where layers slide past each other.

6. Which of the following is a characteristic of turbulent flow? — Formation of eddies and vortices.

7. A fluid is flowing through a pipe. If the flow is streamline, the velocity at any point in the fluid remains: — Constant over time

8. If the viscosity of a fluid decreases, what happens to the terminal velocity of a sphere falling through it, assuming other factors remain constant? — Increases

9. When a fluid flows from a wide section of a pipe to a narrow section at constant volume flow rate, its velocity: — Increases

10. Which property of a fluid determines the magnitude of the force resisting the relative motion of adjacent layers? — Viscosity

11. In the equation for terminal velocity (v_t = 2r²(ρ-σ)g / 9η), what does 'σ' represent? — Density of the fluid

12. Which factor does NOT influence the critical velocity of a fluid in a pipe? — Temperature of the fluid

13. If the density of the fluid and the radius of the sphere are kept constant, doubling the velocity of the sphere falling in a viscous fluid will: — Double the viscous drag force.

14. Viscosity is a measure of a fluid's internal resistance to: — Flow

15. Stokes' Law describes the viscous force acting on a sphere moving through a fluid. What is the formula for this force? — F = 6πηrv

16. When a sphere falls in a fluid, the forces acting on it are gravity, buoyancy, and viscous drag. At terminal velocity, which of the following is true? — Buoyant force + Viscous drag force = Gravitational force

17. The critical velocity for flow through a pipe is generally lower for: — Higher viscosity fluids

18. If the density of a fluid increases, its kinematic viscosity will: — Decrease

19. Which of the following conditions would lead to a higher critical velocity for fluid flow in a pipe? — Increased pipe diameter

20. According to Stokes' Law, the viscous drag force on a sphere is directly proportional to: — Its velocity

21. Stokes' Law is applicable for the motion of: — Small spherical objects in viscous liquids

22. The formula for Reynolds number is given by Re = (ρvD)/η, where ρ is density, v is velocity, D is characteristic length, and η is dynamic viscosity. What does a higher value of ρ indicate for the Reynolds number, assuming other factors are constant? — Higher Reynolds number

23. The resistance to flow in turbulent motion is generally: — Higher than in laminar flow

24. The unit of kinematic viscosity is: — m²/s

25. Terminal velocity is reached when the net force acting on a falling object in a fluid is: — Zero

26. When an object falls through a viscous fluid and reaches terminal velocity, its acceleration is: — Zero

27. The relationship between the viscous force and velocity in streamline flow is: — Linear

28. The unit of viscosity in the CGS system is: — Poise

29. The SI unit of the coefficient of viscosity is: — Pascal-second (Pa·s)

30. Which of the following is NOT a unit of viscosity? — Newton/meter²

31. The coefficient of viscosity of gases generally increases with: — Temperature

32. The coefficient of viscosity of liquids generally decreases with: — Temperature

33. Kinematic viscosity is defined as the ratio of dynamic viscosity to: — Density

34. Poiseuille's law relates the flow rate of a viscous fluid through a pipe to pressure difference, viscosity, and pipe dimensions. The flow rate is inversely proportional to: — Viscosity of the fluid

35. In Stokes' Law (F = 6πηrv), what does 'η' represent? — Coefficient of viscosity of the fluid

36. The terminal velocity of a sphere falling in a viscous fluid is independent of: — Acceleration due to gravity

37. Which of the following is a direct consequence of turbulent flow? — Increased resistance and energy dissipation

38. Turbulent flow is characterized by: — Irregular, chaotic fluid motion with eddies and swirls.

39. For a given pipe and fluid, if the velocity exceeds the critical velocity, the flow regime is likely to become: — Turbulent

40. Which flow regime is associated with higher velocities and greater energy dissipation? — Turbulent flow

41. A high Reynolds number typically indicates: — Turbulent flow

42. Which phenomenon is directly related to the viscosity of the fluid through which an object moves? — Viscous drag

43. The transition from laminar to turbulent flow is influenced by the shape of the object and the: — Viscosity and density of the fluid

44. The terminal velocity of a sphere falling in a viscous fluid is directly proportional to: — The square of its radius

45. Which of the following statements best defines viscosity? — The property of a fluid that opposes relative motion between its layers.

46. The flow of blood in our arteries is typically: — Streamline

47. The Reynolds number (Re) is a dimensionless quantity used to predict the type of fluid flow. What does a low Reynolds number generally indicate? — Streamline (laminar) flow

48. Which of the following represents the correct relationship between streamline and turbulent flow? — Streamline flow occurs at lower velocities, and turbulent flow at higher velocities.

49. Critical velocity is the velocity above which a fluid flow transitions from: — Streamline to turbulent flow

50. If the velocity of a fluid in a pipe is increased beyond the critical velocity, the flow pattern changes from laminar to: — Turbulent

Viscosity, Stokes law, terminal velocity, streamline and turbulent flow, critical velocity - One Line Questions