MCQOPTIONS
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MCQOPTIONS
This section includes 18 Mcqs, each offering curated multiple-choice questions to sharpen your Heat Transfer knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
In turbulent flow |
| A. | the shear stresses are generally larger than in a similar laminar flow |
| B. | fluid particles move in an orderly manner |
| C. | momentum transfer is on a molecular scale only |
| D. | cohesion is more effective than momentum transfer in causing shear stress |
| Answer» B. fluid particles move in an orderly manner | |
| 2. |
\(Q = \frac{{\partial u'}}{{\partial x}} = - \frac{{\partial v'}}{{\partial y}}\) for a turbulent flow signifies |
| A. | conservation of bulk momentum transport |
| B. | increase in u' in x-direction followed by increase in v' in negative y-direction |
| C. | turbulence is anisotropic |
| D. | turbulence is isotropic |
| Answer» C. turbulence is anisotropic | |
| 3. |
Consider the turbulent flow of a fluid through a circular pipe of diameter, D. identify the correct pair of statements.I. The fluid is well-mixedII. The fluid is unmixedIII. ReD < 2300iv. ReD > 2300 |
| A. | I, II |
| B. | II, IV |
| C. | II, III |
| D. | I, IV |
| Answer» E. | |
| 4. |
In turbulent flows through rough pipes, the ration of the maximum velocity to the mean velocity is |
| A. | 2 |
| B. | \(\frac{4}{3}\) |
| C. | 1.1 |
| D. | Dependent on the friction factor |
| Answer» E. | |
| 5. |
‘‘Eddy viscosity’’ means that it is |
| A. | Physical property of the fluid |
| B. | Same as the ‘‘Kinematic viscosity’’ |
| C. | Always associated with laminar flow |
| D. | An apparent viscosity due to turbulent flow |
| Answer» E. | |
| 6. |
Over a flat plate, thickness of turbulent boundary layer at a distance x from leading edge is _____. |
| A. | x4/5 |
| B. | x2/5 |
| C. | x5/4 |
| D. | x3/4 |
| Answer» B. x2/5 | |
| 7. |
In a fully developed turbulent flow through a circular pipe, a head loss of h1 is observed. The diameter of the pipe is increased by 10% for the same flow rate and a head loss of h2 is noted. Assume friction factor for both the cases of pipe flow is the same. The ratio of \(\frac{h_2}{h_1}\) is closest to |
| A. | 0.34 |
| B. | 0.62 |
| C. | 0.87 |
| D. | 1 |
| Answer» C. 0.87 | |
| 8. |
In the moody diagram is shown in the figure below, the friction factor for turbulent flow in the smooth pipe is given by the curve |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» E. | |
| 9. |
In smooth pipes, if R represents Reynold's number, Friction factor for turbulent flow is given by: |
| A. | 0.64/R |
| B. | 64/R |
| C. | 0.316/R1/4 |
| D. | 0.316/R4/5 |
| Answer» D. 0.316/R4/5 | |
| 10. |
During the opening of a valve in pipeline, the flow is |
| A. | Steady |
| B. | Unsteady |
| C. | Uniform |
| D. | None of these |
| Answer» C. Uniform | |
| 11. |
A hydraulic press has a ram of 15 cm diameter and plunger of 1.5 cm. it is required to lift a mass of 1000 kg. The force required on plunger is nearly equal to |
| A. | 100 N |
| B. | 1000 N |
| C. | 10,000 N |
| D. | 10 N |
| Answer» B. 1000 N | |
| 12. |
Flow takes place at Reynolds Number of 1500 in two different pipes with relative roughness of 0.001 and 0.002. The friction factor |
| A. | Will be higher for the pope with relative roughness of 0.001 |
| B. | Will be higher for the pipe having relative roughness of 0.002 |
| C. | Will be the same in both the pipes |
| D. | In the two pipe cannot be compared on the basis of data given |
| Answer» D. In the two pipe cannot be compared on the basis of data given | |
| 13. |
For turbulent flow through the pipe, the pressure drop is a function of. |
| A. | Exponential velocity |
| B. | Square root of velocity |
| C. | Cube of velocity |
| D. | Square of velocity |
| Answer» E. | |
| 14. |
In turbulent flow in a pipe, we know the |
| A. | Reynolds number is greater than 10,000 |
| B. | fluid particles move in straight line |
| C. | head loss varies linearly with flow rate |
| D. | shear stress varies linearly with radius |
| Answer» E. | |
| 15. |
For fully developed turbulent flow though rough pipe at very large Reynolds numbers, friction factor is |
| A. | Dependent on Reynolds numbers only |
| B. | Dependent on relative roughness of pipe only |
| C. | Independent of both Reynolds numbers and relative roughness of pipe |
| D. | Dependent on density of fluid only |
| Answer» C. Independent of both Reynolds numbers and relative roughness of pipe | |
| 16. |
If the particles of a fluid attain such velocities that vary from point to point in magnitude and direction as well as from instant, the flow is _______. |
| A. | Uniform flow |
| B. | Steady flow |
| C. | Turbulent flow |
| D. | Laminar flow |
| Answer» D. Laminar flow | |
| 17. |
Air flows past a cricket ball of 40 mm diameter. It is observed that the boundary layer becomes turbulent at a Reynolds number of 200000. If the kinematic viscosity of air is 1.5 × 10-5 m2/s, then the speed of air when the flow becomes turbulent is: |
| A. | 25 m/s |
| B. | 75 m/s |
| C. | 100 m/s |
| D. | 50 m/s |
| Answer» C. 100 m/s | |
| 18. |
Fluid flow in a straight circular pipe is typically turbulent in nature when the Reynolds number (Re) is ________. |
| A. | 2000 < Re < 4000 |
| B. | Re < 2000 |
| C. | Re > 4000 |
| D. | None of these |
| Answer» D. None of these | |