# Fluid Mechanics and Machinery solved MCQs

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## 1. The specific gravity of a liquid has

a. the same unit as that of mass density

B. the same unit as that of weight density

c. the same unit as that of specific volume

d. no unit

## 2. The specific volume of a liquid is the reciprocal of

a. weight density

B. mass density

c. specific weight

d. specific volume

a. n = m3

B. n = m2

c. n = m

d. n = ms

a. [m1 l-3 t0].

B. [m1 l0 t0].

c. [m0 l-3 t0].

d. [m0 l0 t0].

## 5. Which one of the following is the

a. [m1 l-3 t0].

B. [m-1 l3 t0].

c. [m-1 l-3 t0]. d) [m0 l3 t0].

## 6. the relation between their specific volumes v1 and v2?

a. v1 > v2

B. v1 < v2

c. v1 = v2

d. cannot be determined due to insufficient information.

a. 6:5 kn = m3

B. 6:6 kn = m3

c. 6:7 kn = m3

d. 6:8 kn = m3

a. 0.65

B. 0.66

c. 0.67

d. 0.68

a. 1 l =kg

B. 1:5 l =kg

c. 2 l =kg

d. 2:5 l =kg

## 10. continuity equation is

a. mass conservation

B. zeroth law of thermodynamics

c. first law of thermodynamics

d. energy conservation

## 11. equation of mass conservation into the conservative integral form, which of these theorems is used?

a. stokes theorem

B. kelvin-stokes theorem

c. gauss-siedel theorem

d. gauss divergence theorem

## 12. ρV→. dS→ is positive when

a. the mass flow is outward

B. the mass flow is inward

c. the mass flow is positive

d. the mass flow is negative

## 13. Hydraulic gradient line takes into consideration

a. potential and kinetic heads only

B. potential and pressure heads only

c. kinetic and pressure heads only

d. potential, kinetic and pressure heads

## 14. Which of the following is true?

a. egl always drops in the direction of c

B. egl always rises in the direction of flow

c. egl always remains constant in the direction of flow

d. egl may or may not in the direction of flow

## 15. Which of the following is true?

a. hgl always drops in the direction of flow

B. hgl always rises in the direction of flow

c. hgl always remains constant in the direction of flow

d. hgl may or may not in the direction of flow

## 16. Which of the following is true?

a. hgl will never be above egl

B. hgl will never be under egl

c. hgl will never coincide with egl

d. hgl will may or may not be above egl

## 18. The slope of HGL will be

a. greater than that of egl for a pipe of uniform cross-section

B. smaller than that of egl for a pipe of uniform cross-section

c. equal than that of egl for a pipe of uniform cross-section

d. independent of that of egl for a pipe of uniform cross-section

## 19. For a nozzle, the vertical intercept between EGL and HGL

a. increases

B. decreases

c. remains constant

d. may increase or decrease

## 20. between EGL and HGL

a. increases

B. decreases

c. remains constant

d. may increase or decrease

## 21. Which of the following is true?

a. the slope of egl will always be greater than that of the axis of the pipe

B. the slope of egl will always be smaller than that of the axis of the pipe

c. the slope of egl will always be equal to that of the axis of the pipe

d. the slope of egl will always be independent of that of the axis of the pipe

a. linearly

B. parabolic

c. exponential

d. constant

## 23. When a problem states “The velocity of the water flow in a pipe is 20 m/s”, which of the following velocities is it talking about?

a. rms velocity

B. average velocity

c. absolute velocity

d. relative velocity

## 24. Which of the factors primarily decide whether the flow in a circular pipe is laminar or turbulent?

a. the prandtl number

B. the pressure gradient along the length of the pipe

c. the dynamic viscosity coefficient

d. the reynolds number

## 25. How is Reynolds number defined as?

a. ratio of pressures in the inlet to the outlet of a pipe

B. the product of velocity of the flow and the diameter of the pipe, divided by the kinematic viscosity of fluid

c. the product of density of the fluid, velocity of the flow and the diameter of the pipe, divided by the dynamic viscosity of fluid

d. ratio of inertia force to viscous force