The velocity of steam at throat of the nozzle is __________ the velocity of sound.

The discharge of steam in a convergent-divergent nozzle __________ after the throat (i.e. in the divergent portion of the nozzle)

A

Remains constant

B

Decreases

C

Increases

D

None of these

When the back pressure of a nozzle is below the designed value of pressure at exit of nozzle, the nozzle is said to be

A

Choked

B

Under-damping

C

Over-damping

D

None of these

One day you wake with a sore throat and a runny nose. Your doctor takes a swab from your throat, sends it to a lab, and telephones you the next day to say that antibiotic will not help you get better. Which of the following is the most likely reason for the doctor's statement?

A

Having waited a day, it is too late to take an antibiotic

B

You need an antiseptic, not an antibiotic

C

You need to be vaccinated instead of taking an antibiotic

D

You are infected by a virus

If D is the depth of water upstream of the throat above its sill, B is the width of the throat, to achieve critical flow in an open venturi flume, the theoretical maximum flow Q, is

A

Q = 1.71 $${\text{B}}{{\text{D}}^{\frac{1}{2}}}$$

B

Q = 1.71 BD

C

Q = 1.71 $${\text{B}}{{\text{D}}^{\frac{3}{2}}}$$

D

Q = 1.71 $${\text{B}}{{\text{D}}^{\frac{2}{3}}}$$

In order to avoid tendency of separation at throat in a Venturimeter, the ratio of the diameter at throat to the diameter of pipe should be

A

$$\frac{1}{{16}}$$ to $$\frac{1}{8}$$

B

$$\frac{1}{8}$$ to $$\frac{1}{4}$$

C

$$\frac{1}{4}$$ to $$\frac{1}{3}$$

D

$$\frac{1}{3}$$ to $$\frac{1}{2}$$

The effect of friction on the flow of steam through a nozzle is to decrease the __________ of steam.

A

Wetness

B

Mass flow rate

C

Both A & B

D

Neither A nor B

The critical pressure gives the velocity of steam at the throat

A

Equal to the velocity of sound

B

Less than the velocity of sound

C

More than the velocity of sound

D

None of these

The ratio of exit pressure to inlet pressure of maximum mass flow rate per area of steam through a nozzle when steam is initially superheated is

A

0.555

B

0.578

C

0.5457

D

0.6

The ratio of exit pressure to inlet pressure for maximum mass flow rate per unit area of steam through a nozzle when steam is initially dry saturated is

A

0.6

B

0.578

C

0.555

D

0.5457

The isentropic expansion of steam through nozzle for the steam initially superheated at inlet is approximated by equation

A

pvls=C

B

pv1126 = C

C

pv1A = C

D

pv = C

The velocity of steam at throat of the nozzle is __________ the velocity of sound.

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