Fluid Mechanics MCQ Set 8
FLUID MECHANICS MCQ SET 8
Q1. A streamline cannot intersect another because:
A) Velocity has only one direction at a point
B) Pressure changes
C) Flow becomes unstable
D) Density varies
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Answer: A) Velocity has only one direction at a point
Explanation: If streamlines intersected, a point would have two velocities — impossible in real flow.
Q2. In open channel flow, critical depth corresponds to:
A) Minimum energy
B) Maximum discharge
C) Maximum energy
D) Minimum discharge
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Answer: A) Minimum energy
Explanation: At critical depth, the specific energy of flow is minimum for a given discharge.
Q3. The ratio of actual velocity at vena contracta to theoretical velocity is called:
A) Coefficient of discharge
B) Coefficient of velocity
C) Coefficient of contraction
D) Coefficient of flow
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Answer: B) Coefficient of velocity
Q4. The ratio of area of jet at vena contracta to area of orifice is:
A) Coefficient of discharge
B) Coefficient of contraction
C) Coefficient of velocity
D) None
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Answer: B) Coefficient of contraction
Q5. The discharge of a rectangular notch is proportional to:
A) Head
B) Head²
C) Head³⁄²
D) Head½
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Answer: C) Head³⁄²
Q6. The main function of a manometer is to measure:
A) Flow velocity
B) Pressure difference
C) Temperature
D) Density
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Answer: B) Pressure difference
Explanation: A manometer compares fluid columns to measure pressure difference between two points.
Q7. A simple U-tube manometer can measure:
A) Very high pressure
B) Low pressure
C) Negative pressure
D) Atmospheric pressure only
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Answer: B) Low pressure
Explanation: U-tube manometers are suitable for small pressure differences in low-velocity systems
Q8. A barometer measures:
A) Local fluid pressure
B) Atmospheric pressure
C) Pressure difference
D) Dynamic pressure
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Answer: B) Atmospheric pressure
Explanation: A barometer uses mercury column height to determine atmospheric pressure at a location.
Q9. In a Pitot tube, stagnation pressure is the sum of:
A) Static and kinetic pressure
B) Static and potential pressure
C) Kinetic and dynamic pressure
D) None
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Answer: A) Static and kinetic pressure
Explanation: Stagnation pressure = static pressure + dynamic pressure (½ρV²).
Q10. The boundary layer thickness increases with:
A) Increase in velocity
B) Increase in distance from leading edge
C) Decrease in viscosity
D) None
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Answer: B) Increase in distance from leading edge
Explanation: The boundary layer develops and grows thicker as flow proceeds downstream.