MCQOPTIONS
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MCQOPTIONS
This section includes 39 Mcqs, each offering curated multiple-choice questions to sharpen your NTPC (Technical Ability) knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
A pipe of diameter D conveying a discharge Q is to be replaced by parallel pipes of smaller diameter d to discharge the same quantity. What will be the ratio of \[\frac{D}{d}\,?\](\[f\]Is same for all pipes) |
| A. | \[\frac{D}{d}=2\] |
| B. | \[\frac{D}{d}=\sqrt{2}\] |
| C. | Will decrease |
| D. | \[\frac{D}{d}={{4}^{1/3}}\] |
| Answer» D. \[\frac{D}{d}={{4}^{1/3}}\] | |
| 2. |
A laminar flow is taking place in a pipe. Match List-I (Term) with List-II (Expression) and select the correct answer using the codes given below the lists: List-I (Term) List-II (Expression) A. Discharge, Q 1. \[\frac{16\mu }{\rho \,VD}\] B. Pressure drop, \[\frac{\Delta P}{L}\] 2. \[\frac{\pi \,{{d}^{3}}\Delta p}{128\,\mu L}\] C. Friction factor, \[f\] 3. \[\frac{32\,\mu \,V}{{{D}^{2}}}\] 4. \[\frac{\pi {{d}^{4}}\Delta p}{128\,\mu L}\] Codes: |
| A. | A\[\to \]2, B\[\to \]3, C\[\to \]4 |
| B. | A\[\to \]4, B\[\to \]3, C\[\to \]1 |
| C. | the rotor resistance is high |
| D. | A\[\to \]1, B\[\to \]4, C\[\to \]2 |
| Answer» C. the rotor resistance is high | |
| 3. |
The continuity equation \[\frac{\partial u}{\partial x}+\frac{\partial v}{\partial y}+\frac{\partial w}{\partial z}=0\] is valid only for: |
| A. | Ideal fluid flow |
| B. | Incompressible fluid whether the flow is steady or not |
| C. | \[{{\omega }_{z}}=\frac{1}{2}\,\left( \frac{\partial v}{\partial x}-\frac{\partial v}{\partial y} \right)\] |
| D. | Steady flow and compressible fluids |
| Answer» B. Incompressible fluid whether the flow is steady or not | |
| 4. |
Which one of the following correctly represents the shear stress distribution across a section of a circular pipe having a viscous flow? |
| A. | \[\tau =\frac{\partial p{{r}^{2}}}{\partial x}\] |
| B. | \[\tau =\frac{\partial p\left( r/2 \right)}{\partial x}\] |
| C. | 500 V |
| D. | \[\tau =\frac{\partial p\left( r \right)}{\partial x}\] |
| Answer» D. \[\tau =\frac{\partial p\left( r \right)}{\partial x}\] | |
| 5. |
Which one of the following is the correct statement? A differential manometer connected to a pitotstatic tube used for measuring fluid velocity gives: |
| A. | Static pressure |
| B. | Total pressure |
| C. | About two ampere |
| D. | Difference between total pressure and dynamic pressure. |
| Answer» D. Difference between total pressure and dynamic pressure. | |
| 6. |
In which of the following cases frictional drag is predominating? 1. Tennis ball 2. Parachute 3. Arrow 4. Cyclist |
| A. | 1 and 2 only |
| B. | 2 and 3 |
| C. | \[45\sqrt{2}\,W\] |
| D. | 1, 2 and 3 only |
| Answer» E. | |
| 7. |
The velocity components for a two dimensional incompressible flow of a fluid are \[u=x-4y.\] and \[v=-y-4x.\] It can be concluded that: |
| A. | The flow does not satisfy the continuity equation |
| B. | The flow is rotational |
| C. | 50 |
| D. | None of the above |
| Answer» D. None of the above | |
| 8. |
Consider the following statements: 1. Boundary-layer thickness in laminar flow is greater than that of turbulent flow. 2. Boundary-layer thickness of turbulent flow is greater than that of laminar flow. 3. Velocity distributes uniformly in a turbulent boundary-layer. 4. Velocity has a gradual variation in a laminar boundary layer. Which of the statements given above are correct? |
| A. | 1, 3 and 4 only |
| B. | 1, 2, 3 and 4 |
| C. | \[{{A}_{3}}\] |
| D. | 2, 3 and 4, only |
| Answer» B. 1, 2, 3 and 4 | |
| 9. |
If \[u=ax\] and \[v=-\,ay\] give the velocity distribution for a two-dimensional flow, what is the equation of a stream line passing through the point (3, 1)? |
| A. | \[xy=3\] |
| B. | \[x+y=4\] |
| C. | L/2 |
| D. | \[{{x}^{2}}y=9\] |
| Answer» B. \[x+y=4\] | |
| 10. |
In a two-dimensional fluid flow,\[u=6x+xy.\] which one of the following gives the component of the velocity to satisfy the continuity equation? |
| A. | \[6x+xy\] |
| B. | \[6+xy\] |
| C. | Both are in the same phase |
| D. | \[-\,\left( 6y+\frac{1}{2}\,{{y}^{2}} \right)\] |
| Answer» E. | |
| 11. |
Air (kinematic viscosity \[=15\times {{10}^{-6}}{{\text{m}}^{\text{2}}}\text{/s}\]) with a free stream velocity of 10 m/s flows over a smooth two- dimensional flat plate. If the critical Reynolds number is \[5\times 10,\] what is the maximum distance from the leading edge up to which laminar boundary layer exists? |
| A. | 30 cm |
| B. | 75 cm |
| C. | \[\omega L/R\] |
| D. | 300 cm |
| Answer» C. \[\omega L/R\] | |
| 12. |
How the Von-Karman momentum integral equation expressed is (\[\theta \] is momentum thickness)? |
| A. | \[\frac{{{\tau }_{0}}}{\frac{1}{2}\,\rho \,U_{\infty }^{2}}=\frac{\partial \theta }{\partial x}\] |
| B. | \[\frac{{{\tau }_{0}}}{2\,\rho \,U_{\infty }^{2}}=\frac{\partial \theta }{\partial x}\] |
| C. | Is zero when the circuit contains an ideal inductance only |
| D. | \[\frac{{{\tau }_{0}}}{\frac{1}{3}\,\rho \,U_{\infty }^{2}}=\frac{\partial \theta }{\partial x}\] |
| Answer» D. \[\frac{{{\tau }_{0}}}{\frac{1}{3}\,\rho \,U_{\infty }^{2}}=\frac{\partial \theta }{\partial x}\] | |
| 13. |
The velocity distributions in laminar boundary layer is given by the relation \[u/{{u}_{\infty }}=\,y/\delta .\] what is the momentum thickness for the boundary layer? |
| A. | \[\delta /2\] |
| B. | \[\delta /3\] |
| C. | 33.3 A |
| D. | \[\delta /6\] |
| Answer» E. | |
| 14. |
Which one of the following is the expression of the rotational component for a two-dimensional fluid element in \[x-y\]plane? |
| A. | \[{{\omega }_{z}}=\frac{1}{2}\,\left( \frac{\partial v}{\partial x}-\frac{\partial u}{\partial y} \right)\] |
| B. | \[{{\omega }_{z}}=\frac{1}{2}\,\left( \frac{\partial v}{\partial x}-\frac{\partial u}{\partial y} \right)\] |
| C. | 5 V |
| D. | \[{{\omega }_{z}}=\frac{1}{2}\,\left( \frac{\partial u}{\partial x}+\frac{\partial v}{\partial y} \right)\] |
| Answer» B. \[{{\omega }_{z}}=\frac{1}{2}\,\left( \frac{\partial v}{\partial x}-\frac{\partial u}{\partial y} \right)\] | |
| 15. |
Which one of the following statements is correct? A steady flow of diverging straight steam lines: |
| A. | Is a uniform flow with local acceleration |
| B. | Has convective normal acceleration |
| C. | \[\frac{1}{1000}Hz\] |
| D. | Has both convective normal and tangential accelerations. |
| Answer» E. | |
| 16. |
A circular plate of 1.5 m diameter is submerged in water with its greatest and least depths below the water surface being 2m and 0.75m respectively. When is the approximate magnitude of the total thrust on one face of the plate? |
| A. | 24 kN |
| B. | 28 kN |
| C. | 6 mA |
| D. | 16 kN |
| Answer» B. 28 kN | |
| 17. |
Which of the following relations must hold for an irrotational two-dimensional flow in the \[x-y\] plane: |
| A. | \[\frac{\partial v}{\partial y}-\frac{\partial u}{\partial x}=0\] |
| B. | \[\frac{\partial u}{\partial z}-\frac{\partial v}{\partial x}=0\] |
| C. | 3.2 W |
| D. | \[\frac{\partial v}{\partial x}-\frac{\partial u}{\partial y}=0\] |
| Answer» E. | |
| 18. |
The continuity equation in a differential form is: |
| A. | \[\frac{dA}{A}+\frac{dV}{V}+\frac{dp}{\rho }=\text{constant}\] |
| B. | \[\frac{A}{dA}+\frac{V}{dV}+\frac{\rho }{dp}=\text{constant}\] |
| C. | 8 volts |
| D. | \[AdA+VdV+p\,d\rho =0\] |
| Answer» E. | |
| 19. |
The Bernoulli's equation refers to conservation of: |
| A. | Mass |
| B. | linear momentum |
| C. | 0.48 amp |
| D. | energy |
| Answer» E. | |
| 20. |
Flow separation is caused by: |
| A. | Thinning of boundary layer thickness to zero |
| B. | A negative pressure gradient |
| C. | Datums |
| D. | Reduction of pressure to local vapour pressure |
| Answer» D. Reduction of pressure to local vapour pressure | |
| 21. |
Match List-I (Device) with List-II (Use) and select the correct answer using the codes given below the lists: List-I (Device) List-II (Use) A. Picot tube 1. Boundary shear stress B. Preston tube 2. Turbuleny velocity fluctuations C. Flow Nozzle 3. The total head D. Hot wire anemometer 4. Flow rate Codes: |
| A. | A\[\to \]4, B\[\to \]2, C\[\to \]3, D\[\to \]1 |
| B. | A\[\to \]3, B\[\to \]1, C\[\to \]4, D\[\to \]2 |
| C. | Both a and b |
| D. | A\[\to \]3, B\[\to \]2, C\[\to \]4, D\[\to \]1 |
| Answer» C. Both a and b | |
| 22. |
The velocity potential function in a two dimensional flow fluid is given by \[\phi ={{x}^{2}}-{{y}^{2}}.\] The magnitude of velocity at the point (1, 1) as: |
| A. | 2 |
| B. | 4 |
| C. | "Initial movement of moving parts |
| D. | \[4\,\sqrt{2}\] |
| Answer» D. \[4\,\sqrt{2}\] | |
| 23. |
A metallic piece weighs 80 N in air and 60 N in water. The relative density of the metallic piece is about: |
| A. | 8 |
| B. | 6 |
| C. | be unaffected |
| D. | 2 |
| Answer» E. | |
| 24. |
Match List-I (Nature of equilibrium of floating body) with List-II (Conditions for equilibrium) and select the correct answer using the codes given below the lists: List-I (Nature of equilibrium of floating body) List-II (Conditions for equilibrium) A. Unstable equilibrium 1. \[\overline{MG}\,\,=\,\,0\] B. Netutral equilibrium 2. M is above G M is below G C. Stable equilibrium 4. \[\overline{BG}\,\,=\,\,0\] Where M, G and B are metacentre, Centre of gravity and Centre of buoyancy respectively. Codes: |
| A. | A\[\to \]1, B\[\to \]3, C\[\to \]2 |
| B. | A\[\to \]3, B\[\to \]1, C\[\to \]2 |
| C. | complexities and non-line arties |
| D. | A\[\to \]4, B\[\to \]2, C\[\to \]3 |
| Answer» C. complexities and non-line arties | |
| 25. |
The drag force D on a certain object in a certain flow is a function of the coefficient of viscosity p, the flow speed, V and the body dimension L (for geometrically similar objects); then D is proportional to: |
| A. | \[L\,\mu \,V\] |
| B. | \[\frac{{{\mu }^{2}}{{V}^{2}}}{{{L}^{2}}}\] |
| C. | \[\frac{D}{d}={{4}^{1/5}}\] |
| D. | \[\frac{\mu \,L}{V}\] |
| Answer» B. \[\frac{{{\mu }^{2}}{{V}^{2}}}{{{L}^{2}}}\] | |
| 26. |
Fluid flow rate Q, can be measured easily with the help of a venturi tube, in which the difference of two pressures, \[\Delta \,P,\] measured at an upstream point and at the smallest cross-section of the tube, is used. If a relation \[\Delta \,P\propto {{Q}^{n}}\] exists, then n is equal to: |
| A. | \[\frac{1}{3}\] |
| B. | \[\frac{1}{2}\] |
| C. | \[\tau =-\,\,\frac{\partial p\left( r/2 \right)}{\partial x}\] |
| D. | 2 |
| Answer» E. | |
| 27. |
A stepped pipeline with four different cross-sections discharges water at the rate of 2 litres per second. Match List-I (Areas of pipe is sq. cm) with List-II (velocities of water in cm/s) and select the correct answer using the codes given below the list: List-I List-II A. 500 1. 4 B. 100 2. 5 C. 400 3. 10 D. 200 4. 15 5. 20 Codes: |
| A. | A\[\to \]5, B\[\to \]1, C\[\to \]2, D\[\to \]3 |
| B. | A\[\to \]1, B\[\to \]4, C\[\to \]2, D\[\to \]3 |
| C. | Dynamic pressure |
| D. | A\[\to \]3, B\[\to \]2, C\[\to \]5, D\[\to \]1 |
| Answer» C. Dynamic pressure | |
| 28. |
If the governing equation for a flow field is given by \[{{\nabla }^{2}}\phi \,=\,0\] and the velocity is given by \[\overrightarrow{V}\,=\,\nabla \phi ,\] the: |
| A. | \[\nabla \times \overrightarrow{\nabla }=0\] |
| B. | \[\nabla \times \overrightarrow{V}=1\] |
| C. | 2, 3 and 4 only |
| D. | \[(\overrightarrow{\nabla }.\nabla )\,\overrightarrow{\nabla }=\frac{\partial \,\overrightarrow{\nabla }}{\partial \,t}\] |
| Answer» B. \[\nabla \times \overrightarrow{V}=1\] | |
| 29. |
Which of the following is not a dimensionless group? |
| A. | \[\frac{\Delta \,p}{\rho \,{{N}^{2}}{{D}^{2}}}\] |
| B. | \[\frac{g\,H}{{{N}^{2}}\,{{D}^{2}}}\] |
| C. | The flow is irrotational |
| D. | \[\frac{\Delta \,p}{\rho \,{{V}^{3}}}\] |
| Answer» E. | |
| 30. |
Consider the following statements: 1. Gases are considered incompressible when Mach number is less than 0.2 2. A Newtonian fluid is incompressible and non- viscous 3. An ideal fluid has negligible surface tension which of these statements (s) is/are correct? |
| A. | 2 and 3 |
| B. | 2 alone |
| C. | \[x+3y=6\] |
| D. | 1 and 3 |
| Answer» C. \[x+3y=6\] | |
| 31. |
Consider the following coefficients: (Re = Reynold number) 1. \[1.328\,\,{{\operatorname{Re}}^{-\,\left( 0.5 \right)}}\] for laminar flow 2. \[0.72\,\,{{\operatorname{Re}}^{-\,\left( 0.2 \right)}}\] for turbulent flow 3. \[0.072\,\,{{\operatorname{Re}}^{-\,\left( 0.2 \right)}}\] for turbulent flow 4. \[1.028\,\,{{\operatorname{Re}}^{-\,\left( 0.5 \right)}}\] for laminar flow. The Coefficients for drag for a flat plate would include: |
| A. | 1 and 2 |
| B. | 2 and 4 |
| C. | 150 cm |
| D. | 3 and 4 |
| Answer» D. 3 and 4 | |
| 32. |
At the interface of a liquid and a gas at rest, the pressure is: |
| A. | Higher on the concave side compared to that on the convex side |
| B. | Higher on the convex side compared to that on the concave side |
| C. | \[\frac{{{\tau }_{0}}}{\rho \,U_{\infty }^{2}}=\frac{\partial \theta }{\partial x}\] |
| D. | Equal to surface tension divided by radius of curvature on both sides |
| Answer» E. | |
| 33. |
A hydraulic jump is formed in a 5.0 wide rectangular channel with sequent depths of 0.2 m and 0.8 m. The discharge in the channel, in \[{{\text{m}}^{\text{3}}}\text{/s,}\] is: |
| A. | 2.43 |
| B. | 3.45 |
| C. | \[\delta /4\] |
| D. | 5 |
| Answer» D. 5 | |
| 34. |
A liquid mass readjusts itself and undergoes a rigid body type of motion when it is subjected to a: |
| A. | Constant angular velocity |
| B. | Constant angular acceleration |
| C. | Has convective tangential acceleration |
| D. | Linearly varying acceleration |
| Answer» C. Has convective tangential acceleration | |
| 35. |
A type of flow in which the fluid particles while moving in the direction of flow rotate about their mass centre, is called |
| A. | steady flow |
| B. | uniform flow |
| C. | 12 kN |
| D. | rotational flow |
| Answer» E. | |
| 36. |
Venturimeter is used to measure flow of fluids in pipes when pipe is; |
| A. | horizontal |
| B. | vertical, flow downwards |
| C. | \[\frac{\partial w}{\partial y}-\frac{\partial v}{\partial z}=0\] |
| D. | In any position |
| Answer» E. | |
| 37. |
The centre of pressure of a plane submerged surface : |
| A. | should coincide with centroid of surface |
| B. | should coincide with centroid of pressure prism |
| C. | \[\frac{dA}{A}+\frac{dV}{V}+\frac{dp}{\rho }=0\] |
| D. | cannot be above mentioned |
| Answer» E. | |
| 38. |
Compressibility\[(\beta )\]is equal to: (If k is bulk modulus) |
| A. | \[\beta =\frac{1}{k}\] |
| B. | \[\beta =k\] |
| C. | Angular momentum |
| D. | \[\beta ={{k}^{2}}\] |
| Answer» B. \[\beta =k\] | |
| 39. |
A control volume refers to |
| A. | a closed system |
| B. | a specified mass |
| C. | A\[\to \]4, B\[\to \]1, C\[\to \]3 |
| D. | a fixed region in space |
| Answer» E. | |