Fluid Mechanics MCQ Set 1
FLUID MECHANICS MCQ SET 1
Q1. Which branch of science deals with the study of fluids at rest or in motion?
A) Thermodynamics
B) Fluid Mechanics
C) Heat Transfer
D) Solid Mechanics
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Answer: B) Fluid Mechanics
Explanation: Fluid Mechanics studies the behavior of fluids (liquids and gases) whether stationary or in motion.
Q2. The density of water at 4°C is approximately:
A) 1000 kg/m³
B) 1020 kg/m³
C) 998 kg/m³
D) 950 kg/m³
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Answer: A) 1000 kg/m³
Explanation: At 4°C, water reaches its maximum density, approximately 1000 kg/m³.
Q3. Which of the following is a dimensionless quantity?
A) Velocity
B) Pressure
C) Reynolds Number
D) Viscosity
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Answer: C) Reynolds Number
Explanation: Reynolds number is a ratio of inertial to viscous forces and has no physical dimensions.
Q4. The unit of dynamic viscosity in SI system is:
A) N·s/m²
B) Pa·s
C) Both A and B
D) N/m²
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Answer: C) Both A and B
Explanation: 1 Pascal-second (Pa·s) = 1 N·s/m²; both represent dynamic viscosity in SI units.
Q5. Which of the following fluids is incompressible?
A) Air
B) Steam
C) Water
D) Gasoline
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Answer: C) Water
Explanation: Liquids like water are treated as incompressible since their volume change with pressure is negligible.
Q6. Continuity equation is based on the law of:
A) Conservation of Mass
B) Conservation of Momentum
C) Conservation of Energy
D) Thermodynamics
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Answer: A) Conservation of Mass
Explanation: The continuity equation states that mass entering a control volume equals the mass leaving it.
Q7. Bernoulli’s equation applies to:
A) Viscous flow
B) Steady, incompressible, inviscid flow
C) Compressible flow
D) Turbulent flow
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Answer: B) Steady, incompressible, inviscid flow
Explanation: Bernoulli’s theorem is valid only for steady and frictionless flow along a streamline.
Q8. The SI unit of pressure is:
A) Pascal
B) Bar
C) Newton
D) Joule
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Answer: A) Pascal
Explanation: Pressure = Force/Area; 1 Pascal = 1 N/m².
Q9. The viscosity of a liquid generally:
A) Increases with temperature
B) Decreases with temperature
C) Remains constant
D) Becomes zero
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Answer: B) Decreases with temperature
Explanation: As temperature increases, intermolecular forces reduce, decreasing viscosity.
Q10. The viscosity of gases:
A) Decreases with temperature
B) Increases with temperature
C) Remains constant
D) Is independent of temperature
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Answer: B) Increases with temperature
Explanation: Higher temperature causes faster molecular motion, increasing gas viscosity.