MCQOPTIONS
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MCQOPTIONS
This section includes 30 Mcqs, each offering curated multiple-choice questions to sharpen your Fluid Mechanics knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Oil flows through a 200 mm diameter horizontal cast iron pipe (friction factor, f = 0.0225) of length 500 m. The volumetric flow rate is 0.2 m3/s. The head loss (in m) due to friction is (assume g = 9.81 m/s2) |
| A. | 116.18 |
| B. | 0.116 |
| C. | 18.22 |
| D. | 232.36 |
| Answer» B. 0.116 | |
| 2. |
A piping system consists of three pipes arranged in series, the lengths of the pipes are 1200 m, 750 m and 600 m and diameters 750 mm, 600 mm, 450 mm respectively. Transform the system to an equivalent 450 mm diameter pipe |
| A. | 671.3 m |
| B. | 771.3 m |
| C. | 871.3 m |
| D. | 971.3 m |
| Answer» D. 971.3 m | |
| 3. |
A pipeline connecting two reservoirs has its diameter reduced by 20% due to deposition of chemicals. For a given head difference in the reservoirs with unaltered friction factor, this would cause a reduction in discharge of |
| A. | 42.8% |
| B. | 20% |
| C. | 17.8% |
| D. | 10.6% |
| Answer» B. 20% | |
| 4. |
Point A of head HA is at a higher elevation than point B of head HB. The head loss between these points is HL. The flow will take place |
| A. | Always form A to B |
| B. | From A to B if HA = HB + HL |
| C. | From B to A if HA + HL = HB |
| D. | From B to A if HB + HL = HA |
| Answer» C. From B to A if HA + HL = HB | |
| 5. |
Oil flows through a 200 mm diameter horizontal pipe with friction factor (4f) = 0.02. The length of the pipe is 50 m and volumetric flow rate is 0.314 m3/s. The head loss in the pipe due to friction is (g = 10 m/s2). |
| A. | 50 m |
| B. | 25 m |
| C. | 100 m |
| D. | 5 m |
| Answer» C. 100 m | |
| 6. |
For a fully–developed flow of water in a pipe having a diameter 10 cm, velocity 0.2 m/s, and kinetic viscosity 10-5 m2/s, what is the value of the Darcy friction factor? |
| A. | 6.4 |
| B. | 0.032 |
| C. | 0.064 |
| D. | 0.64 |
| Answer» C. 0.064 | |
| 7. |
Assertion A: Loss of head at a sudden expansion of a pipe is larger than that at a sudden contraction.Reason R: Separation of flow occurs at sudden contractionsWhich of the following is correct? |
| A. | A is false but R is true. |
| B. | A is true but R is false. |
| C. | Both A and R are true, but R is not a correct explanation of A. |
| D. | Both A and R are true, and R is the correct explanation of A. |
| Answer» D. Both A and R are true, and R is the correct explanation of A. | |
| 8. |
If the velocity of pressure wave generated is 2 m/s, the value of critical time is: _____. |
| A. | 2 s |
| B. | 4 s |
| C. | 1 s |
| D. | 0.5 s |
| Answer» D. 0.5 s | |
| 9. |
Minor losses in a pipe flow are those losses |
| A. | which are insignificantly small |
| B. | Which can always be neglected |
| C. | caused by local disturbance due to pipe fittings |
| D. | caused by frictional resistance |
| E. | caused by the temperature of the fluid being conducted at room temperature |
| Answer» D. caused by frictional resistance | |
| 10. |
Pipe 1, branches to three pipes as shown in the given figure. The areas and corresponding velocities are as given in the following table. The value of V2 in cm per second will bePipeVelocity(cm per second)Area(sq cm)1.2.3.4.50V2302020101510 |
| A. | 15 |
| B. | 20 |
| C. | 30 |
| D. | 35 |
| Answer» E. | |
| 11. |
A pipeline of 300 mm diameter carrying water at an average velocity of 5 metre/sec branches into two pipes of 150 mm and 200 diameter. The total flow rate of discharge of water in the system is |
| A. | 58 litres/sec |
| B. | 132 litres/sec |
| C. | 353 litres/sec |
| D. | 832 litres/sec |
| Answer» D. 832 litres/sec | |
| 12. |
A tank open at the top with a water level of 1 m, as shown in the figure, has a hole at a height of 0.5 m. A free jet leaves horizontally from the smooth hole. The distance X (in m) where the jet strikes the floor is |
| A. | 0.5 |
| B. | 1 |
| C. | 2 |
| D. | 4 |
| Answer» C. 2 | |
| 13. |
A smooth pipe of diameter 100 mm and length 100 m carries crude oil (Kinematic viscosity = 0.4 stokes and density = 900 kg/m3 at velocity of 2 m/s. What will be the power (in W) required to maintain the flow? [ Friction factor = 0.03, g = 10 m/s2] |
| A. | 282.7 |
| B. | 565.4 |
| C. | 848.2 |
| D. | 1130.9 |
| Answer» D. 1130.9 | |
| 14. |
Loss of head at Exit of pipe is calculated by - |
| A. | \(0.375 \dfrac{v^2}{2g}\) |
| B. | \(0.5\dfrac{v^2}{2g}\) |
| C. | \(0.25\dfrac{v^2}{2g}\) |
| D. | \(\dfrac{v^2}{2g}\) |
| Answer» E. | |
| 15. |
Consider steady flow of an incompressible fluid through two long and straight pipes of diameters d1 and d2 arranged in series. Both pipes are of equal length and the flow is turbulent in both pipes. The friction factor for turbulent flow though pipes is of the form, f = K(Re)-n, where K and n are known positive constants and Re is the Reynolds number. Neglecting minor losses, the ratio of the frictional pressure drop in pipe 1 to that in pipe 2, \(\left( {\frac{{{\rm{\Delta }}{P_1}}}{{{\rm{\Delta }}{P_2}}}} \right),\) is given by |
| A. | \({\frac{{{d_2}}}{{{d_1}}}^{5 - n}}\) |
| B. | \({\frac{{{d_2}}}{{{d_1}}}^5}\) |
| C. | \({\frac{{{d_2}}}{{{d_1}}}^{3 - n}}\) |
| D. | \({\frac{{{d_2}}}{{{d_1}}}^{5 + n}}\) |
| Answer» B. \({\frac{{{d_2}}}{{{d_1}}}^5}\) | |
| 16. |
Oil flows through a 200 mm diameter horizontal cast iron pipe (friction factor, f = 0.0225) of length 500 m. The volumetric flow rate is 0.2 m3/s. The head loss (in m) due to friction is (assume g = 9.81 m/s2) |
| A. | 116.18 |
| B. | 0.116 |
| C. | 18.22 |
| D. | 232.36 |
| Answer» B. 0.116 | |
| 17. |
Head loss due to friction in a circular pipe of diameter D, under laminar flow, is inversely proportional to: |
| A. | D3 |
| B. | D2 |
| C. | D5 |
| D. | D4 |
| Answer» E. | |
| 18. |
Minor losses in a piping system are |
| A. | Less than the friction losses \(f~\frac{l}{d^2}\frac{v^2}{g}\) |
| B. | Due to the viscous stresses |
| C. | Assumed to vary linearly with the velocity |
| D. | Found by using loss coefficients |
| Answer» E. | |
| 19. |
In a 1920 m long pipeline, the velocity of propagation of pressure wave is 960 m/s. The rapid closure of a downstream valve will entail, when the maximum time for the closure is: |
| A. | 8 s |
| B. | 2 s |
| C. | 6 s |
| D. | 4 s |
| Answer» E. | |
| 20. |
A tube is used (as shown in the below figure) as a siphon to discharge an oil of specific gravity 0.8 from a large open vessel into a drain at atmospheric pressure. The velocity of oil through the siphon will be |
| A. | 1.5 m/s |
| B. | 6.7 m/s |
| C. | 8.8 m/s |
| D. | 10.4 m/s |
| Answer» E. | |
| 21. |
A head loss in a sudden expansion from 6 cm diameter pipe to 12 cm diameter pipe in terms of velocity v1 in the smaller diameter pipe is |
| A. | \(\frac{3}{{16}}\frac{{v_1^2}}{{2g}}\) |
| B. | \(\frac{5}{{16}}\frac{{v_1^2}}{{2g}}\) |
| C. | \(\frac{7}{{16}}\frac{{v_1^2}}{{2g}}\) |
| D. | \(\frac{9}{{16}}\frac{{v_1^2}}{{2g}}\) |
| Answer» E. | |
| 22. |
Find the loss of head due to friction in a smooth pipe of rectangular cross section of 1 m × 0.5 m and 10 m long. Velocity of flow is 10 m/s and the friction coefficient is 0.01962. |
| A. | 4 m |
| B. | 6 m |
| C. | 8 m |
| D. | 10 m |
| Answer» C. 8 m | |
| 23. |
Pipes of length l1, l2 etc and diameters d1, d2, etc. are connected in series. A single pipe of length l1 + l2 + l3 + …. having same pressure loss as all pipes in series will have diameter equal to |
| A. | \({\left( {\frac{{{l_1} + {l_2} + {l_3} + \ldots }}{{\frac{{{l_1}}}{{d_1^4}} + \frac{{{l_2}}}{{d_2^4}} + \ldots }}} \right)^{\frac{1}{4}}}\) |
| B. | \({\left( {\frac{{{l_1} + {l_2} + {l_3} + \ldots }}{{\frac{{{l_1}}}{{d_1^5}} + \frac{{{l_2}}}{{d_2^5}} + \ldots }}} \right)^{\frac{1}{5}}}\) |
| C. | \({\left( {\frac{{{l_1} + {l_2} + {l_3} + \ldots }}{{\frac{{{l_1}}}{{d_1^3}} + \frac{{{l_2}}}{{d_2^3}} + \ldots }}} \right)^{\frac{1}{3}}}\) |
| D. | \({\left( {\frac{{{l_1} + {l_2} + {l_3} + \ldots }}{{\frac{{{l_1}}}{{d_1^2}} + \frac{{{l_2}}}{{d_2^2}} + \ldots }}} \right)^{\frac{1}{2}}}\) |
| Answer» C. \({\left( {\frac{{{l_1} + {l_2} + {l_3} + \ldots }}{{\frac{{{l_1}}}{{d_1^3}} + \frac{{{l_2}}}{{d_2^3}} + \ldots }}} \right)^{\frac{1}{3}}}\) | |
| 24. |
In a locomotive, the effect of “hammer blow” can be reduced by: |
| A. | decreasing the speed and having pairs of wheels coupled together |
| B. | increasing the speed |
| C. | balancing whole of the reciprocating parts |
| D. | uncoupling the pairs of wheels |
| Answer» B. increasing the speed | |
| 25. |
A smooth pipe of diameter 200 mm carries water. The pressure in the pipe at section S1 (elevation: 10 m) is 50kPa. At Section S2 (elevation: 12 m) the pressure is 20 kPa and velocity is 2 ms-1. Density of water is 1000 kgm-3 and acceleration due to gravity is 9.8 ms-2. Which of the following is TRUE? |
| A. | flow from S1 to S2 and head loss is 0.53 m |
| B. | flow from S2 to S1 and head loss is 0.53 m |
| C. | flow from S1 to S2 and head loss is 1.06 m |
| D. | flow from S2 to S1 and head loss is 1.06 m |
| Answer» D. flow from S2 to S1 and head loss is 1.06 m | |
| 26. |
A 1 m long and 12 cm diameter straight pipe is laid at a uniform downgrade and flow rate is maintained such that velocity head in the pipe is 0.5 m. If the pressure in the pipe is observed to be uniform along the length when the down slope of the pipe is 1 in 10, What is the friction factor for the pipe? |
| A. | 0.012 |
| B. | 0.024 |
| C. | 0.042 |
| D. | 0.050 |
| Answer» C. 0.042 | |
| 27. |
At point A in a pipeline carrying water, the diameter is 1 m, the pressure 98 kPa and the velocity 1 m/s. At point B, 2 m higher than A, the diameter is 0.5 m and the pressure 20 kPa. The direction of flow would be |
| A. | A to B |
| B. | B to A |
| C. | Cannnot be ascertained from data |
| D. | None of these |
| Answer» B. B to A | |
| 28. |
A pipe 500 mm in diameter is 981 m long. It delivers water at a velocity of 2 m/s. The loss of head when f = 0.008 is |
| A. | 20.2 m |
| B. | 12.8 m |
| C. | 35.6 m |
| D. | 6.4 m |
| Answer» C. 35.6 m | |
| 29. |
A compound pipeline consists of two pieces of identical pipes. The equivalent length of same diameter and same friction factor, for the compound pipeline is L1 when pipes are connected in series, and is L2 when connected is parallel. What is the ratio of equivalent lengths L1 to L2? |
| A. | 32 : 1 |
| B. | 8 : 1 |
| C. | 2 : 1 |
| D. | √2 : 1 |
| Answer» C. 2 : 1 | |
| 30. |
If (L) is the total head at inlet and (1) is the head loss due to friction, efficiency of power transmission through a straight pipe is given by |
| A. | \(\frac{{L - 1}}{L}\) |
| B. | \(\frac{{L - 1}}{{L + 1}}\) |
| C. | \(\frac{L}{{L + 1}}\) |
| D. | \(\frac{L}{{L - 1}}\) |
| Answer» B. \(\frac{{L - 1}}{{L + 1}}\) | |