Virtual Labs

1. In a short cylindrical external mouthpiece, the vena contracta occurs at approximately what distance from the entrance?

a: Equal to the diameter of the orifice Explanation

Explanation

b: One-fourth of the diameter of the orifice Explanation

Explanation

c: One-half of the diameter of the orifice Explanation

Explanation

d: Twice the diameter of the orifice Explanation

Explanation

2. Which type of mouthpiece generally has the highest coefficient of discharge?

a: Convergent-divergent mouthpiece Explanation

Explanation

b: External cylindrical mouthpiece Explanation

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c: Internal mouthpiece Explanation

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d: Borda's mouthpiece Explanation

Explanation

3. The coefficient of discharge of a mouthpiece is defined as the ratio of:

a: Theoretical discharge to actual discharge Explanation

Explanation

b: Actual velocity to theoretical velocity Explanation

Explanation

c: Actual discharge to theoretical discharge Explanation

Explanation

d: Area at vena contracta to area of orifice Explanation

Explanation

4. Why does a cylindrical external mouthpiece discharge more fluid than an orifice under the same head?

a: Because the jet expands and fills the mouthpiece after vena contracta formation Explanation

Explanation

b: Because friction losses are absent Explanation

Explanation

c: Because atmospheric pressure becomes zero Explanation

Explanation

d: Because the fluid density increases Explanation

Explanation

5. In a convergent-divergent mouthpiece, the diverging portion is provided mainly to:

a: Increase energy losses Explanation

Explanation

b: Reduce pressure recovery Explanation

Explanation

c: Decrease the discharge Explanation

Explanation

d: Convert velocity head into pressure head Explanation

Explanation

6. Which quantity is experimentally measured to determine the coefficient of discharge of a mouthpiece?

a: Actual discharge Explanation

Explanation

b: Atmospheric pressure Explanation

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c: Pipe roughness Explanation

Explanation

d: Specific gravity of air Explanation

Explanation

7. Which theorem is applied to derive the theoretical discharge equation for a mouthpiece?

a: Pascal's law Explanation

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b: Archimedes' principle Explanation

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c: Bernoulli's theorem Explanation

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d: Newton's law of viscosity Explanation

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8. Cavitation in a mouthpiece is most likely to occur when:

a: Pressure inside the mouthpiece falls below vapor pressure Explanation

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b: Velocity becomes zero Explanation

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c: The fluid density increases Explanation

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d: The coefficient of discharge exceeds unity Explanation

Explanation

9. For a given head, a convergent-divergent mouthpiece provides greater discharge because it:

a: Eliminates gravity effects Explanation

Explanation

b: Provides better pressure recovery and minimizes losses Explanation

Explanation

c: Increases fluid viscosity Explanation

Explanation

d: Reduces the area at the outlet to zero Explanation

Explanation

Mouthpieces Experiment