laboursonline – MCQs, Mock Tests | Engineering Civil Engineering -MCQS-Hydraulics Section 2

Liquids

1. cannot be compressed
2. do not occupy definite shape
3. are not affected by change in pressure and temperature
4. none of these.

✅ Correct Answer: 2

The ratio of the inertia and gravitational force acting in any flow, ignoring other forces, is called

1. Euler number
2. Frode number
3. Reynold number
4. Weber number.

✅ Correct Answer: 2

Non-over flow double curvature concrete arch, is provided in

1. Bhakra dam
2. Hirakund dam
3. Nagarjuna Sagar dam
4. Idukki dam.

✅ Correct Answer: 4

For the most economical trapezoidal open channel,

1. half of the top width must be equal to one of the sloping sides
2. the hydraulic mean depth must be equal to half the depth of flow
3. the semicircle drawn with top width as diameter must touch the three sides of the channel
4. All of these.

✅ Correct Answer: 4

Hydraulic ram is a device

1. for lifting water without an electric motor
2. for accelerating water flow
3. for lifting heavy loads
4. none of these.

✅ Correct Answer: 1

Gauge pressure is

1. absolute pressure - atmospheric pressure
2. absolute pressure + atmospheric pressure
3. atmospheric pressure - absolute pressure
4. none of these.

✅ Correct Answer: 1

If jet of water coming out from a nozzle with a velocity 9.81 m/s, the angle of elevation being 30°, the time to reach the highest point is

1. 0.25 s
2. 0.50 s
3. 1.0 s
4. 1.5 s.

✅ Correct Answer: 2

The discharge through a 100 mm diameter external mouth piece fitted to the side of a large vessel is 0.05948 m3/s. The head over the mouth piece is

1. 2 m
2. 2.5 m
3. 3.0 m
4. 4.0 m.

✅ Correct Answer: 4

If cohesion between the molecules of a fluid is more than adhesion between the fluid and glass, the free level of fluid in a dipped glass tube will be

1. higher than the surface of liquid
2. same as the surface of liquid
3. lower than the surface of liquid
4. none of these.

✅ Correct Answer: 3

The continuity equation

1. expresses the relationship between work and energy
2. relates the momentum per unit volume between two points on a stream line
3. relates mass rate of flow along a stream line
4. requires that Newton's second law of motion be satisfied at every point in fluid.

✅ Correct Answer: 3

In pipe lines, a surge tank is provided

1. to relieve the pressure due to water hammer
2. to provide additional water head
3. to overflow the pipe line when suddenly closed
4. to remove the frictional loss in pipe.

✅ Correct Answer: 1

Total head of a liquid particle in motion is the sum of

1. potential head and kinetic head
2. kinetic head and pressure head
3. potential head and pressure head
4. potential head, kinetic head and pressure head.

✅ Correct Answer: 4

The velocity distribution of viscous fluid through a circular/pipe is :

1. hyperbolic
2. circular
3. parabolic
4. elliptical.

✅ Correct Answer: 3

Mercury is generally used in barometers because

1. its vaour pressure is practically zero
2. the height of the barometer will be less
3. it is a best liquid
4. both (a) and (b) above

✅ Correct Answer: 4

Flow in pipes is laminar if Reynold number is

1. less than 2100
2. more than 3000
3. between 2100 and 3000
4. none of these.

✅ Correct Answer: 1

In flow, the liquid particles may possess

1. potential energy
2. kinetic energy
3. pressure energy
4. all the above.

✅ Correct Answer: 4

Euler's equation for the motion of liquids assumes that

1. fluid is viscous
2. fluid is homogeneous and incompressible
3. velocity of flow is non-uniform over the section
4. flow is unsteady along the stream line.

✅ Correct Answer: 2

The height of water level in a tank above the centre of a circular hole 2.5 cm in diameter is 50 m. The velocity of water flowing through the hole, is

1. 31.1 m/sec
2. 31.2 m/sec
3. 31.3 m/sec
4. 31.4 m/sec.

✅ Correct Answer: 3

A steady uniform flow is through

1. a long pipe at decreasing rate
2. a long pipe at constant rate
3. an expanding tube at constant rate
4. an expanding tube at increasing rate

✅ Correct Answer: 2

Cavitation is caused by

1. Low pressure
2. High pressure
3. Low velocity
4. High velocity

✅ Correct Answer: 1

Mach number is the ratio of inertia force to

1. viscosity
2. surface tension
3. gravitational force
4. elasticity.

✅ Correct Answer: 4

The main assumption of Bernoulli's equation is :

1. The velocity of energy of liquid particle, across any cross-section of a pipe is uniform
2. No external force except the gravity acts on the liquid
3. There is no loss of energy of the liquid while flowing
4. All the above.

✅ Correct Answer: 4

For critical depth of flow of water in open channels, fc the specific energy must be :

1. minimum
2. maximum
3. average of maximum and minimum
4. None of these.

✅ Correct Answer: 1

Kinematic viscosity of liquids by equation is determined by :

1. Redwood viscometer
2. Engler viscometer
3. Saybolt universal viscometer
4. None of these.

✅ Correct Answer: 3

If the forces are due to inertia and gravity, and frictional resistance plays only a minor role, the design of the channels is made by comparing

1. Reynold number
2. Froude number
3. Weber number
4. Mach number.

✅ Correct Answer: 2

The velocity of the fluid particle at the centre of the pipe section, is

1. minimum
2. maximum
3. equal throughout
4. none of these.

✅ Correct Answer: 2

Due to decrease of diameter of the droplet, inside pressure intensity

1. increases
2. decreases
3. remains unaffected
4. None of these.

✅ Correct Answer: 1

In order to avoid capillary correction, the minimum diameter of a manometer used for measuring pressure, should be

1. 2 mm
2. 4 mm
3. 6 mm
4. 10 mm

✅ Correct Answer: 3

When water flows over a rectangular suppressed weir, the negative pressure created beneath the nappe

1. increases the discharge
2. decreases the discharge
3. does not effect the discharge
4. none of these.

✅ Correct Answer: 1

Barometres are used to measure

1. pressure in water channels, pipes etc.
2. difference in pressure at two points
3. atmospheric pressure
4. very low pressure

✅ Correct Answer: 3

For most economical rectangular section of a channel, the depth is kept

1. one-fourth of the width
2. three times the hydraulic radius
3. half the width
4. hydraulic mean depth

✅ Correct Answer: 3

In a centrifugual pump casing, the flow of water leaving the impeller, is

1. rectilinear flow
2. radial flow
3. free vortex motion
4. forced vertex.

✅ Correct Answer: 3

In fluids, steady flow occurs when

1. conditions of flow change steadily with time
2. conditions of flow do not change with time at a point
3. conditions of flow remain the same at adjacent point
4. velocity vector remains constant at a point.

✅ Correct Answer: 2

From a nozzle exposed to atmosphere, the liquid jet traverses

1. a straight line
2. a circular path
3. an elliptical path
4. a parabolic path.

✅ Correct Answer: 4

To avoid the force of surface tension in an inclined manometer, the minimum angle of inclination is

1. 2°
2. 3°
3. 4°
4. 5°

✅ Correct Answer: 3