Mechanical Properties of Fluids Mock Test – Class 11 Physics

1. A body floats at rest on a liquid surface. The force balance on the body is

2. The buoyant force on a body fully immersed in a liquid is increased when

3. Terminal velocity is reached by a small sphere falling in a viscous fluid when

4. A Venturi tube has throat speed times the speed in the wide section. If the wide-section speed is and the liquid density is , the pressure difference is

5. A sphere is falling at terminal velocity through a liquid. Its weight is , and the buoyant force is . The viscous drag at that instant is

6. Relative density compares the density of a substance with the density of

7. A spherical liquid drop has surface tension and radius . The excess pressure inside the drop is

8. A rectangular block of height and horizontal area is fully immersed in water. The top face is at depth . Take and . The net upward force due to pressure on the top and bottom faces is

9. A diver moves from depth to depth in water. Take and . The increase in gauge pressure is

10. In a hydraulic system, the small piston is pressed down slowly. The large piston lifts a heavy object. The reason a small input force can lift a heavy load is best described as

11. For flow through a pipe, Reynolds number is commonly written as

12. The derivation of capillary rise equates the upward surface-tension force around the rim to the

13. A small plane surface of area experiences a uniform pressure of . If the surface is turned to a different orientation at a point where the pressure is unchanged, the magnitude of force on it is

14. A liquid drop tends to become spherical mainly because surface tension tends to

15. Detergent is added to water on which small insects were able to stand. The insects may sink more easily because detergent

16. The hydrostatic paradox refers to the idea that the pressure at the base of a liquid-filled vessel depends on

17. A Venturi meter is calibrated for an ideal liquid flow in a horizontal tube. If the same pressure difference is measured but the actual flow is strongly viscous with large energy loss, the ideal calculation may

18. In a simple description of surface tension, the free surface of a liquid behaves somewhat like

19. A liquid flows steadily through a pipe. The mass flow rate is the same at two sections mainly because

20. Which pair is correctly matched?

21. Consider the following statements about pressure variation in a liquid at rest.
Statement I: Gauge pressure increases linearly with depth.
Statement II: At the same depth in the same connected liquid, pressure is the same.
Statement III: The slope of a gauge-pressure versus depth graph is .

22. A cube floats in water with of its volume submerged. The same cube is then placed in a liquid of density . If the cube floats again, the fraction of its volume submerged in the new liquid is

23. A person applies force on a piston of area . Another piston has twice the area and receives the same pressure. What force acts on the second piston?

24. Standard atmospheric pressure is commonly written as . Its approximate value in pascal is

25. A manometer gives the same height difference first with water and then with mercury. For the same , the pressure difference indicated by mercury is larger because mercury has

26. A common classroom comparison says that honey is more viscous than water. This means honey

27. A wide tank and a narrow tube are connected at the bottom and contain the same liquid at rest. The liquid levels are the same in both arms. The pressure at two bottom points at the same horizontal level is

28. A sealed syringe filled completely with water has its outlet blocked. When the plunger is pushed gently, the pressure increase is felt throughout the water because the fluid is

29. In a Bunsen burner, gas flowing through a narrow jet helps draw air through side holes. The Bernoulli-related idea is that the fast gas stream

30. A liquid drop of radius splits into identical smaller drops. If the original excess pressure was , the excess pressure in each smaller drop is

31. A sealed container has of gas of mass . If the gas is compressed to without loss of mass, its density becomes

32. Use the arrangement described below.

Which pair should be classified as fluids?

33. Assertion: Water generally rises near the wall of a clean glass capillary.
Reason: Water wets glass and has an acute angle of contact with it.

34. Use the arrangement described below.

The water level in the pressure tube at Q is expected to be

35. The SI unit of surface tension is

36. Stokes’ law is most suitable when the motion of the sphere through the fluid is

37. A glass capillary is dipped in mercury. The meniscus is expected to be

38. Study the table and identify the correct graph interpretation.

39. A tank of total water height has a small hole at depth below the free surface. The hole is therefore at height above the ground. Under ideal conditions, the horizontal range of the jet is maximum when

40. Pressure is introduced in fluid mechanics as

41. In the capillary formula , a liquid rises in the tube when

42. An open-tube manometer contains mercury of density . The mercury level difference is , with the connected gas side lower. Take . The gauge pressure of the gas is

43. Water of density flows through a pipe of diameter with speed . If , the Reynolds number is

44. A U-tube manometer is mainly used to measure

45. A pressure of acts uniformly on an area of . What normal force is acting on the area?

46. A claim says: “A larger force always means a larger pressure.” The best response is that the claim is incomplete because pressure also depends on

47. In a pipe carrying ideal fluid, section P is lower and section Q is higher. If the speeds at P and Q are equal, then compared with pressure at Q, pressure at P is

48. Two vessels of different shapes contain the same liquid up to the same vertical height. If their bottom points are at the same depth, the pressure at those bottom points is

49. A block floats in water with half its volume submerged. When the same block floats in another liquid, only of its volume is submerged. Compared with water, the other liquid is

50. A liquid stream emerging from a tap has area and speed at the tap. At a lower point, its speed has become . If the flow is steady and incompressible, the stream area there is