Veda AI Learning & Classroom
Get the app
For teachers Teacher overview Answer key generator Quiz generator Question paper generator Attendance app Student reports All free tools
For students Student overview Solve a question paper NCERT syllabus Flashcard maker Important questions Play a challenge Daily GK quiz
For schools Schools overview Start a pilot Tuition & coaching Teaching diary
Library NCERT syllabus Study kits by subject Browse every topic Previous year papers Board paper solutions Blog
Your account Log in — teachers, students & schools About Veda Get the app — free

Fluid Flow Basics: 18 MCQs with answers

All 18 multiple-choice questions from this kit, free and with no sign-up.

Full kit · everything Flashcards · 18 Quick Revision · 14

Warm-up · 7 questions

Q1. Which of the following is the SI unit of dynamic viscosity?

Beginner
A Pa·s B m²/s C kg/m³ D N/m
Show answer & explanation

Pa·s

Dynamic viscosity is measured in Pascal-seconds (Pa·s) in the SI system.

Q2. The Reynolds number is defined as the ratio of inertial forces to which of the following?

Beginner
A Surface tension forces B Pressure forces C Viscous forces D Gravitational forces
Show answer & explanation

Viscous forces

Reynolds number (Re = ρVD/μ) quantifies the relative importance of inertial to viscous forces.

Q3. Which of the following is the primary driving force for fluid flow in a horizontal pipe?

Beginner
A Pressure difference B Viscosity C Surface tension D Gravity
Show answer & explanation

Pressure difference

In a horizontal pipe, gravity has no component along the flow direction, so pressure difference drives the flow.

Q4. Which of the following instruments is used to measure the flow rate of a fluid in a pipe?

Beginner
A Thermometer B Venturi meter C Manometer D Barometer
Show answer & explanation

Venturi meter

A Venturi meter measures flow rate by creating a pressure drop in a converging-diverging section.

Q5. Which of the following is true for a fluid with high viscosity?

Beginner
A It has lower density B It has higher surface tension C It flows more easily D It resists flow more than a low-viscosity fluid
Show answer & explanation

It resists flow more than a low-viscosity fluid

Viscosity is a measure of a fluid's internal resistance to flow; higher viscosity means more resistance.

Q6. Which of the following is the correct expression for the hydraulic diameter of a circular pipe?

Beginner
A D_h = πD B D_h = D/2 C D_h = D D D_h = 2D
Show answer & explanation

D_h = D

For a circular pipe, the hydraulic diameter equals the actual diameter, D_h = 4A/P = 4(πD²/4)/(πD) = D.

Q7. The Bernoulli equation can be applied across a pump that adds energy to the fluid.

Beginner
A True B False
Show answer & explanation

False

Bernoulli's equation applies to inviscid flow without external energy addition; pumps add energy, so a modified energy equation is needed.

Building up · 11 questions

Q8. For an incompressible fluid, the continuity equation simplifies to which of the following?

Intermediate
A P₁ + ρgh₁ = P₂ + ρgh₂ B ρ₁A₁V₁ = ρ₂A₂V₂ C V₁/A₁ = V₂/A₂ D A₁V₁ = A₂V₂
Show answer & explanation

A₁V₁ = A₂V₂

For incompressible flow, density is constant, so the continuity equation reduces to A₁V₁ = A₂V₂.

Q9. In laminar flow through a circular pipe, the velocity profile is which of the following?

Intermediate
A Parabolic B Uniform C Linear D Hyperbolic
Show answer & explanation

Parabolic

Laminar flow in a pipe has a parabolic velocity profile, with maximum velocity at the center.

Q10. Which of the following represents the Bernoulli equation for an incompressible, inviscid fluid along a streamline?

Intermediate
A P + ½ρV² + ρgh = constant B P + ρV² + ρgh = constant C P + ρV + ρgh = constant D P + ½ρV + ρgh = constant
Show answer & explanation

P + ½ρV² + ρgh = constant

Bernoulli's equation states that the sum of pressure, kinetic energy per unit volume (½ρV²), and potential energy per unit volume (ρgh) is constant.

Q11. The Darcy friction factor for laminar flow in a pipe is given by which of the following?

Intermediate
A Re/64 B 0.316/Re^0.25 C 64/Re D 16/Re
Show answer & explanation

64/Re

For laminar flow, the Darcy friction factor is f = 64/Re, derived from the Hagen-Poiseuille equation.

Q12. The head loss due to friction in a pipe is directly proportional to which of the following?

Intermediate
A Length of the pipe B Diameter of the pipe C Density of the fluid D Cross-sectional area
Show answer & explanation

Length of the pipe

Darcy-Weisbach equation shows head loss h_f = f (L/D) (V²/2g), so it is proportional to pipe length L.

Q13. In a pump, the net positive suction head (NPSH) is important to avoid which of the following?

Intermediate
A Water hammer B Friction loss C Cavitation D Surge
Show answer & explanation

Cavitation

Insufficient NPSH causes the local pressure to drop below the vapor pressure, leading to cavitation.

Q14. The critical Reynolds number for transition from laminar to turbulent flow in a circular pipe is approximately which of the following?

Intermediate
A 4000 B 10000 C 2300 D 1000
Show answer & explanation

2300

For pipe flow, the critical Reynolds number is about 2300; below this, flow is typically laminar.

Q15. Which of the following is a dimensionless number used to characterize compressible flow?

Intermediate
A Reynolds number B Weber number C Froude number D Mach number
Show answer & explanation

Mach number

Mach number (Ma = V/c) is the ratio of flow velocity to the speed of sound, important for compressible flows.

Q16. In a fully developed laminar pipe flow, the average velocity is what fraction of the maximum velocity?

Intermediate
A 0.75 B 0.67 C 1.0 D 0.5
Show answer & explanation

0.5

For laminar flow with a parabolic profile, the average velocity is exactly half the maximum velocity.

Q17. The Hagen-Poiseuille equation for laminar flow in a pipe relates pressure drop to which of the following?

Intermediate
A Mach number B Volumetric flow rate C Friction factor D Reynolds number
Show answer & explanation

Volumetric flow rate

Hagen-Poiseuille equation gives ΔP = 128μLQ/(πD⁴), directly relating pressure drop to volumetric flow rate Q.

Q18. In turbulent flow, the velocity profile is flatter than in laminar flow.

Intermediate
A True B False
Show answer & explanation

True

Turbulent flow has a more uniform velocity profile due to mixing, making it flatter than the parabolic laminar profile.

Open the full Fluid Flow Basics kit Flashcards · 18 Quick Revision · 14
Make your own

Your notes can be a kit like these

Every kit here was made from real study material. Point Veda at a chapter, a PDF, a photo or a link and get notes, flashcards, practice MCQs, games and a scored test — free, in 42 languages.

  • Chapter notes
  • Flashcards
  • Practice MCQs
  • Scored tests
  • Exam prep

Get Veda free See what students get

Free to start · No ads · Works in 42 languages