Most important MCQ Questions Answers and Solution for GATE and Other Competitive Examinations from the Chapter Properties of Fluids in Fluid Mechanics

1. An ideal fluid is defined as the fluid which is

- [accordion]
- Options
- A. compressible

B incompressible

C incompressible and non-viscous (Inviscid)

D has negligible surface tension - Answer
- C incompressible and non viscous
- Solution
- Real fluid- has viscosity

Newtonian Fluids - real fluid which obey newton's law, shear stress is proportional to the velocity gradient or rate of shear strain

Non Newtonian fluid - a real fluid which doesn't obey newton's law

2. Newton's law of viscosity states that

- [accordion]
- Options
- A shear stress is directly proportional to the velocity

B shear stress is directly proportional to the velocity gradient

C Shear stress is directly proportional to the shear strain

D shear stress is directly proportional to the viscosity - Answer
- B, Shear stress is directly proportional to the velocity gradient
- Solution
- Shear stress is directly proportional to the velocity gradient or directly proportional to the rate of shear strain. In the option C only shear strain is written, if it is written as rate of shear strain the option will be also correct

3. A Newtonian fluid is defined as the fluid which

- [accordion]
- Options
- A is incompressible and non-viscous

B obey's Newtons law of viscosity

C is highly viscous

D is compressible and non-viscous - Answer
- B obeys Newtons law of viscosity
- Solution
- Newtons law of viscosity

4. Kinematic viscosity is defined as equal to

- [accordion]
- Options
- A dynamic viscosity x density

B dynamic viscosity / density

C dynamic viscosity x pressure

D pressure x density - Answer
- B dynamic viscosity / density
- Solution
- Kinematic Viscosity

5. Dynamic viscosity has the dimensions as

- [accordion]
- Options
- A MLT-2

B ML-1T-1

C ML-1T-2

D M-1L-1T-1 - Answer
- B ML-1T-1
- Solution
- Dynamic Viscosity

6. Poise is the unit of

- [accordion]
- Options
- A mass density

B kinematic viscosity

C viscosity

D velocity gradient - Answer
- C viscosity
- Solution
- Dynamic Viscosity

7. The increase of temperature

- [accordion]
- Options
- A) increases the viscosity of liquid

B) decreases the viscosity of liquids

C) decreases the viscosity of gas

D) increases the viscosity of gas - Answer
- B and D
- Solution
- Viscosity and Temperature relation

8. Stock is a unit of

- [accordion]
- Options
- A mass density

B kinematic viscosity

C viscosity

D velocity gradient - Answer
- B Kinematic Viscosity
- Solution
- Equation of Kinematic Virtuosity

9. the dividing factor for converting one poise into MKS unit is

- [accordion]
- Options
- A 9.81

B 98.1

C 981

D 0.981 - Answer
- B 98.1
- Solution
- Dynamic Viscosity

10. Surface tension has the unit of

- [accordion]
- Options
- A Force per unit area

B force per unit length

C force per unit volume

D none of the above - Answer
- B force per unit length
- Solution
- or surface energy per unit area

11. The gases are considered incompressible when

- [accordion]
- Options
- A equal to 1

B equal to 0.50

C greater than 0.3

D less than 0.2 - Answer
- D less than 0.2
- Solution

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