MCQOPTIONS
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MCQOPTIONS
This section includes 31 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. |
Submarines use principle of ‘neutral buoyancy’ to go into the water. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 2. |
As a balloon rises in the air its volume increases, at the end it acquires a stable height and cannot rise any further. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 3. |
Assertion: A needle placed carefully on the surface of the water may float, whereas a ball of the same material will always sink.Reason: The buoyancy of an object depends both on the material and shape of the object |
| A. | Both assertion and reason are true and the reason is the correct explanation of the assertion |
| B. | Both assertion and reason are true but the reason is not the correct explanation of the assertion |
| C. | Assertion is true but the reason is false |
| D. | Assertion and reason is false |
| Answer» D. Assertion and reason is false | |
| 4. |
The water droplets in free fall are spherical due to ___________ |
| A. | Gravity |
| B. | Viscosity |
| C. | Surface tension |
| D. | Intermolecular attraction |
| Answer» D. Intermolecular attraction | |
| 5. |
A wooden block is taken to the bottom of a deep, calm lake of water and then released. It rises up with a ___________ |
| A. | Constant acceleration |
| B. | Decreasing acceleration |
| C. | Constant velocity |
| D. | Decreasing velocity |
| Answer» B. Decreasing acceleration | |
| 6. |
Spherical balls of radius R are falling in a viscous fluid of viscosity Ƞ with a velocity v. The retarding viscous force acting on the spherical ball is ___________ |
| A. | Directly proportional to R but inversely proportional to v |
| B. | Directly proportional to both radius R and velocity v |
| C. | Inversely proportional to both radius R and velocity v |
| D. | Inversely proportional to R but directly proportional to velocity v |
| Answer» C. Inversely proportional to both radius R and velocity v | |
| 7. |
A boat having a length of 3m and breadth 2m is floating on a lake. The boat sinks by one cm when a man gets on it. What is the mass of the man? |
| A. | 6kg |
| B. | 60kg |
| C. | 16kg |
| D. | 600kg |
| Answer» C. 16kg | |
| 8. |
A solid weight 6kg in air. If its density is 2000kgm-3, what will be its apparent weight in water? |
| A. | 6kg |
| B. | 2kg |
| C. | 3kg |
| D. | 5kg |
| Answer» D. 5kg | |
| 9. |
Assertion: A hydrogen filled balloon stops using after it has attained a certain height in the sky.Reason: The atmospheric pressure decreases with height and becomes zero when maximum height is attained. |
| A. | Both assertion and reason are true and the reason is the correct explanation of the assertion |
| B. | Both assertion and reason are true but the reason is not the correct explanation of the assertion |
| C. | Assertion is true but the reason is false |
| D. | Assertion and reason is false |
| Answer» D. Assertion and reason is false | |
| 10. |
When the temperature is increased, the angle of contact of a liquid? |
| A. | Increase |
| B. | Decrease |
| C. | Remains the same |
| D. | First increases and then decreases |
| Answer» B. Decrease | |
| 11. |
In incompressible fluid flows steadily through a cylindrical pipe which had a radius 2R at point A and R at a point B further along the flow direction. If the velocity at A is v, then that at B is? |
| A. | v/2 |
| B. | v |
| C. | 2v |
| D. | 4v |
| Answer» E. | |
| 12. |
A_WOODEN_BLOCK_IS_TAKEN_TO_THE_BOTTOM_OF_A_DEEP,_CALM_LAKE_OF_WATER_AND_THEN_RELEASED._IT_RISES_UP_WITH_A?$ |
| A. | Constant acceleration |
| B. | Decreasing acceleration |
| C. | Constant velocity |
| D. | Decreasing velocity |
| Answer» B. Decreasing acceleration | |
| 13. |
AS_A_BALLOON_RISES_IN_THE_AIR_ITS_VOLUME_INCREASES,_AT_THE_END_IT_ACQUIRES_A_STABLE_HEIGHT_AND_CANNOT_RISE_ANY_FURTHER.?$ |
| A. | True |
| B. | False |
| Answer» B. False | |
| 14. |
Assertion: A needle placed carefully on the surface of the water may float, whereas a ball of the same material will always sink.$ |
| A. | |
| B. | Both assertion and reason are true and the reason is the correct explanation of the assertion |
| C. | Both assertion and reason are true but the reason is not the correct explanation of the assertion |
| Answer» D. | |
| 15. |
The_water_droplets_in_free_fall_are_spherical_due_to$ |
| A. | Gravity |
| B. | Viscosity |
| C. | Surface tension |
| D. | Intermolecular attraction |
| Answer» D. Intermolecular attraction | |
| 16. |
Submarines_use_principle_of_‘neutral_buoyancy’_to_go_into_the_water.$# |
| A. | True |
| B. | False |
| Answer» B. False | |
| 17. |
Spherical balls of radius R are falling in a viscous fluid of viscosity Ƞ with a velocity v. The retarding viscous force acting on the spherical ball i?# |
| A. | Directly proportional to R but inversely proportional to v |
| B. | Directly proportional to both radius R and velocity v |
| C. | Inversely proportional to both radius R and velocity v |
| D. | Inversely proportional to R but directly proportional to velocity v |
| Answer» C. Inversely proportional to both radius R and velocity v | |
| 18. |
What happens to the buoyant force acting on the airship as it rises in the air? |
| A. | Buoyant force increases |
| B. | Buoyant force decreases |
| C. | Buoyant force remains constant |
| D. | Buoyant force first increases then shows decrease |
| Answer» C. Buoyant force remains constant | |
| 19. |
It is difficult to cook food at the mountain. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 20. |
How can relatively denser object be made to float on the less dense fluid? |
| A. | By altering the shape. |
| B. | By altering the forces acting on the object |
| C. | By altering the shear forces acting on the object |
| D. | None of the mentioned |
| Answer» B. By altering the forces acting on the object | |
| 21. |
A boat having a length of 3m and breadth 2m is floating on a lake. The boat sinks by one cm, when a man gets on it. What is the mass of the man? |
| A. | 6kg |
| B. | 60kg |
| C. | 16kg |
| D. | 600kg |
| Answer» C. 16kg | |
| 22. |
What is the principal cause of action of buoyant force on a body submerged partially or fully in fluid? |
| A. | Displacement of fluid due to submerged body |
| B. | Development of force due to dynamic action |
| C. | Internal shear forces mitigating external forces |
| D. | None of the mentioned |
| Answer» B. Development of force due to dynamic action | |
| 23. |
A solid weight 6kg in air. If its density is 2000kgm-3, what will be its apparent weight in water? |
| A. | 6kg |
| B. | 2kg |
| C. | 3kg |
| D. | 5kg |
| Answer» D. 5kg | |
| 24. |
Find the density of metallic body which floats at the interface of mercury of sp.gr 13.6 and water such that 40 % of its volume is sub-merged in mercury and 60% in water. |
| A. | 6040 kg/m<sup>3</sup> |
| B. | 12080 kg/m<sup>3</sup> |
| C. | 24160 kg/m<sup>3</sup> |
| D. | 3020 kg/m<sup>3</sup> |
| Answer» B. 12080 kg/m<sup>3</sup> | |
| 25. |
A cube of wood floating in water supports a 200g mass at the centre of its top face. When the mass is removed, the mass rises by 2cm. Determine the volume of cube. |
| A. | 1000cm<sup>3</sup> |
| B. | 100cm<sup>3</sup> |
| C. | 10cm<sup>3</sup> |
| D. | 1cm<sup>3</sup> |
| Answer» B. 100cm<sup>3</sup> | |
| 26. |
A body of dimensions 2.7 m * 3.8 m * 2.5 m, weighs 2500 N in water.Find its weight in air. |
| A. | 254.12 kN |
| B. | 508.25 kN |
| C. | 101.65 kN |
| D. | 127.06 kN |
| Answer» B. 508.25 kN | |
| 27. |
Assertion: A hydrogen filled balloon stops using after it has attained a certain height in the sky |
| A. | |
| B. | Both assertion and reason are true and the reason is the correct explanation of the assertion |
| C. | Both assertion and reason are true but the reason is not the correct explanation of the assertion |
| Answer» D. | |
| 28. |
A stone weighs 650 N in air and 275 N in water. Compute its specific gravity. |
| A. | 1.73 |
| B. | 2.45 |
| C. | 3.46 |
| D. | 0.865 |
| Answer» B. 2.45 | |
| 29. |
When the temperature is increased, the angle of contact of a liquid |
| A. | Increase |
| B. | Decrease |
| C. | Remains the same |
| D. | First increases and then decreases |
| Answer» B. Decrease | |
| 30. |
A stone weighs 450 N in air and 200 N in water. Compute the volume of stone. |
| A. | .025 m<sup>3</sup> |
| B. | .05 m<sup>3</sup> |
| C. | .075 m<sup>3</sup> |
| D. | None of the mentioned |
| Answer» B. .05 m<sup>3</sup> | |
| 31. |
Find the position of centre of buoyancy for a wooden block of width 3.5 m and depth 1 m, when it floats horizontally in water. The density of wooden block id 850 kg/m3 and its length 7.0 m. |
| A. | 0.95 |
| B. | 0.85 |
| C. | 1.05 |
| D. | 1.65 |
| Answer» C. 1.05 | |