Our valuable visitors, TheFluidMechanic provides **Fluid Mechanics MCQ** (multiple choice questions) and their model answers. The following multiple choice **Fluid Mechanics** questions are very essential for quizzes, campus tests, semester midterm and final exams, engineering job interviews (civil engineering, mechanical engineering and chemical engineering) and competitive exams like **The Principles and Practice of Engineering (PE) exam**, **The Fundamentals of Engineering (FE) exam** and **GATE**. These multiple choice questions are developed for engineering students and professionals of different disciplines, these model questions are asked frequently in online technical tests and across interviews of engineering consultants and firms.

**Start now with Fluid Mechanics MCQ - Energy Equation - Set 1**

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#### Question No.1

The **Bernoulli equation** is written with usual notation as \[z + \frac{p}{\gamma } + \frac{{{v^2}}}{{2g}} = {\rm{constant}}\]

In this equation **each of the terms represents** :

- energy in kg.m/kg mass of fluid
- energy in N.m/kg mass of fluid
- energy in N.m/N weight of fluid
- power in kW/kg mass of fluid

#### Question No.2

The **velocity** in a cross section is **non-uniform**. In **one-dimensional** method of analysis, the **kinetic energy per unit weight** is :

- \[\frac{{{v^2}}}{{2g}}\]
- \[\alpha \frac{{{v^2}}}{{2g}}\]
- \[\beta \frac{{{v^2}}}{{2g}}\]
- \[\frac{p}{\gamma }\]

#### Question No.3

**Bernoulli equation** is **applicable** between **any two points** :

- in any rotational flow of an incompressible fluid
- in any type of irrotational flow of a fluid
- in steady rotational flow of an incompressible fluid
- in steady irrotational flow of an incompressible fluid

#### Question No.4

Indicate the **incorrect** statement :

For **Bernoulli equation** as \[z + \frac{p}{\gamma } + \frac{{{v^2}}}{{2g}} = {\rm{constant}}\]to be **applicable** :

- the flow must be steady
- the fluid must be an ideal gas
- the flow must be irrotational
- the fluid must be incompressible

#### Question No.5

The **piezometric head** of a flow is :

- the sum of the velocity head and datum head
- the sum of the pressure head and datum head
- the sum of the pressure head and velocity head
- the sum of the velocity head, pressure head and datum head

#### Question No.6

In a flow of a **real fluid** with **no addition of energy** :

- the energy line will be horizontal or sloping upward in the direction of flow
- the energy line can never be horizontal or sloping upward in the direction of flow
- the piezometric line can never be horizontal or sloping downward in the direction of flow
- the center line of the pipe can never be above the energy line

#### Question No.7

Indicate the **incorrect** statement :

- The hydraulic grade line and the energy line are coincident for a body of fluid at rest
- Whenever the hydraulic grade line falls below the center line of a conduit carrying a liquid, the local pressures are less than the reference atmospheric pressure
- The hydraulic grade line in a flow of real fluid with addition of energy will have an upward slope in the direction of flow
- The energy line in a flow of an ideal fluid with no addition of energy will always be horizontal

#### Question No.8

The **total head** in a flow is the **sum** of :

- piezometric head and datum head
- piezometric head and pressure head
- piezometric head and velocity head
- piezometric head, velocity head and datum head

#### Question No.9

The **difference** between the **total head line** and the **hydraulic grade line** represents :

- the velocity head
- the piezometric head
- the pressure head
- the elevation head

If you are searching for more

Fluid Mechanics MCQ(Multiple Choice Questions)covering differentFluid Mechanicstopics, you can check the following MCQs.

#### Question No.10

In a pipeline, the **hydraulic grade line** is **above** the pipe **center line** in the longitudinal section at **point A** and **below** the pipe **center line** at another **point B**. From this it can be inferred that :

- vacuum pressure prevail at B
- vacuum pressures prevail at A
- the flow is from A to B
- the flow is from B to A

#### Question No.11

The **kinetic energy correction factor α **is defined as :

- \[\frac{1}{{{A^3}{V^3}}}\int {{v^3}dA} \]
- \[\frac{1}{A}\int {{v^3}dA} \]
- \[\frac{1}{{A{V^3}}}\int {vdA} \]
- \[\frac{1}{{A{V^3}}}\int {{v^3}dA} \]

Where *V* is the average velocity.

#### Question No.12

In a two-dimensional duct flow, air flows in the bottom half of the duct with uniform velocity and there is no flow in the upper half. The value of the **kinetic energy correction factor α **for this flow is :

- 2.0
- 2.25
- 4.0
- 3.0

#### Question No.13

A 15 cm diameter pipe carries a flow of 70 lit/s of oil (relative density = 0.75). At a section 12 cm above the datum, the pressure is vacuum of 2 cm of mercury. If the **kinetic energy correction factor α** for this section is 1.1, the

**total head**at the section in meters of oil is :

- 0.648
- 0.728
- 0.557
- 0.637

#### Question No.14

In connection with the flow of a fluid in a pipe, the following statement regarding the **kinetic energy correction factor α** is

**correct**:

*α*_{laminar flow}<*α*_{turbulent flow}*α*_{laminar flow}=*α*_{turbulent flow}*α*_{laminar flow}= 2_{ }*α*_{laminar flow}= 1.33

#### Question No.15

A 20 cm diameter horizontal pipe is attached to a tank containing water. The water level in the tank is 7 m above the pipe outlet and the pipe discharges into the atmosphere. Assuming a total loss of 3 m in the pipe and the kinetic energy correction factor *α* of the jet issuing from the pipe to be 1.20, the **discharge in the pipe** in lit/s is :

- 254
- 278
- 368
- 305

#### Question No.16

Water flows **steadily** down a **vertical** pipe of **constant cross section**. Neglecting friction, according to **Bernoulli's equation** :

- pressure is constant along the length of the pipe
- velocity decreases with height
- pressure decreases with height
- pressure increases with height

#### Question No.17

In the **siphon** shown in the following figure assuming **ideal** flow, **pressure p_{B}** :

- \[ = {p_A}\]
- \[ < {p_A}\]
- \[ > {p_A}\]
- \[ = {p_C}\]

#### Question No.18

A **jet of air** is directed over a **circular cylinder** as shown in the following figure. Neglecting viscous effects, the **force acting on the cylinder** due to air motion is :

- upwards
- downwards
- in the direction of jet flow
- zero

#### Question No.19

The following figure shows a **tank being emptied** by a pipe of length *L*. If the friction of the pipe is neglected, the **pressure at a point A** at the pipe inlet would :

- increase if the length
*L*is increased - be constant and equal to
*γL* - remain constant at
*γH*for all lengths*L* - decrease with an increase in
*L*

#### Question No.20

In a fluid flow, **point A** is at a **higher elevation** than **point B**. The **head loss** between these points is *H _{L}*. The total heads at A and B are

*H*and

_{a}*H*respectively. The flow will take place :

_{b}- from A to B if
*H*+_{a}*H*=_{L}*H*_{b} - from B to A if
*H*+_{a}*H*=_{L}*H*_{b} - always from A to B
- from B to A if
*H*+_{b}*H*=_{L}*H*_{a}

After you have checked the **Fluid Mechanics MCQ**, you can check the **model answers** for those MCQ on the following link :

**Start now with Fluid Mechanics MCQ - Energy Equation - Set 1**

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