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| fluid mechanics mcq with answers 2026 |
🟢 Introduction
Are you preparing for SSC JE, GATE, or other mechanical engineering exams?
In this article, you will find 30+ important Fluid Mechanics MCQs with answers that will help you strengthen your concepts and improve your exam preparation for 2026. These questions are selected based on previous exam patterns and important topics.
📘 Fluid Mechanics MCQ with Answers
Basic Concepts
Q1. What is the unit of viscosity?
A) Pascal
B) Newton
C) Pascal-second
D) Joule
👉 Answer: C) Pascal-second
Q2. Which fluid has the highest viscosity?
A) Water
B) Air
C) Oil
D) Petrol
👉 Answer: C) Oil
Q3. Reynolds number is used to determine?
A) Pressure
B) Flow type
C) Velocity
D) Density
👉 Answer: B) Flow type
Q4. Bernoulli’s equation is based on?
A) Energy conservation
B) Mass conservation
C) Momentum
D) Heat transfer
👉 Answer: A) Energy conservation
Q5. Laminar flow occurs at Reynolds number?
A) > 4000
B) < 2000
C) = 3000
D) > 10000
👉 Answer: B) < 2000
Q6. The unit of pressure is?
A) Pascal
B) Watt
C) Joule
D) Newton
👉 Answer: A) Pascal
Q7. Specific gravity is the ratio of?
A) Density to weight
B) Density of fluid to density of water
C) Volume to mass
D) Pressure to density
👉 Answer: B) Density of fluid to density of water
Q8. Which instrument measures pressure?
A) Venturimeter
B) Manometer
C) Rotameter
D) Pitot tube
👉 Answer: B) Manometer
Q9. Continuity equation represents?
A) Energy conservation
B) Mass conservation
C) Momentum
D) Pressure
👉 Answer: B) Mass conservation
Q10. Turbulent flow occurs when Reynolds number is?
A) < 2000
B) 2000–4000
C) > 4000
D) = 1000
👉 Answer: C) > 4000
Flow & Properties
Q11. Density is defined as?
A) Mass/Volume
B) Volume/Mass
C) Force/Area
D) Energy/Volume
👉 Answer: A) Mass/Volume
Q12. Kinematic viscosity is?
A) Dynamic viscosity/density
B) Density/viscosity
C) Pressure/velocity
D) Force/area
👉 Answer: A) Dynamic viscosity/density
Q13. SI unit of density is?
A) kg/m³
B) N/m²
C) Joule
D) Watt
👉 Answer: A) kg/m³
Q14. What is compressibility?
A) Change in volume with pressure
B) Change in pressure with volume
C) Change in density with temperature
D) None
👉 Answer: A) Change in volume with pressure
Q15. Ideal fluid has?
A) No viscosity
B) High density
C) High pressure
D) Zero velocity
👉 Answer: A) No viscosity
Pressure & Measurement
Q16. Absolute pressure is?
A) Atmospheric + gauge pressure
B) Gauge pressure only
C) Vacuum pressure
D) None
👉 Answer: A) Atmospheric + gauge pressure
Q17. Gauge pressure is measured with?
A) Barometer
B) Manometer
C) Thermometer
D) Hygrometer
👉 Answer: B) Manometer
Q18. Vacuum pressure is?
A) Above atmospheric
B) Below atmospheric
C) Equal atmospheric
D) Zero
👉 Answer: B) Below atmospheric
Q19. Pressure increases with?
A) Height
B) Depth
C) Temperature
D) Velocity
👉 Answer: B) Depth
Q20. Unit of specific weight is?
A) N/m³
B) kg/m³
C) Pascal
D) Joule
👉 Answer: A) N/m³
Flow Measurement
Q21. Venturimeter measures?
A) Pressure
B) Velocity
C) Flow rate
D) Density
👉 Answer: C) Flow rate
Q22. Pitot tube measures?
A) Pressure
B) Velocity
C) Flow rate
D) Temperature
👉 Answer: B) Velocity
Q23. Rotameter works on?
A) Variable area principle
B) Pressure principle
C) Velocity principle
D) Density principle
👉 Answer: A) Variable area principle
Q24. Discharge is?
A) Volume/time
B) Mass/time
C) Force/time
D) Energy/time
👉 Answer: A) Volume/time
Q25. Flow rate unit is?
A) m³/s
B) kg/s
C) N/s
D) J/s
👉 Answer: A) m³/s
Energy & Bernoulli
Q26. Bernoulli equation applies to?
A) Ideal fluid
B) Real fluid
C) Solid
D) Gas only
👉 Answer: A) Ideal fluid
Q27. Total energy includes?
A) Pressure energy
B) Kinetic energy
C) Potential energy
D) All
👉 Answer: D) All
Q28. Hydraulic grade line represents?
A) Pressure head
B) Velocity head
C) Total head
D) Energy loss
👉 Answer: A) Pressure head
Q29. Energy line is always?
A) Below HGL
B) Above HGL
C) Equal HGL
D) None
👉 Answer: B) Above HGL
Q30. Losses in pipe are due to?
A) Friction
B) Turbulence
C) Bends
D) All
👉 Answer: D) All
Miscellaneous
Q31. Surface tension is?
A) Force per length
B) Energy per volume
C) Force per area
D) Pressure
👉 Answer: A) Force per length
Q32. Capillarity is due to?
A) Viscosity
B) Surface tension
C) Density
D) Pressure
👉 Answer: B) Surface tension
Q33. Pascal’s law is related to?
A) Pressure transmission
B) Energy
C) Flow
D) Heat
👉 Answer: A) Pressure transmission
Q34. Flow in pipe is mostly?
A) Laminar
B) Turbulent
C) Uniform
D) Steady
👉 Answer: B) Turbulent
Q35. Cavitation occurs due to?
A) High pressure
B) Low pressure
C) High velocity
D) Low temperature
👉 Answer: B) Low pressure
