Mechanical Properties of Fluids Mock Test – Class 11 Physics

1. A fluid is between two large parallel plates. The lower plate is fixed, and the upper plate pulls the top fluid layer steadily. If the velocity changes linearly from at the lower plate to at a distance , the velocity gradient is

2. The dimensional formula of coefficient of viscosity is

3. A stone weighs in air and when fully immersed in water. The buoyant force on the stone is

4. A beginner writes four symbol-unit pairs for fluid mechanics. Select the pair that is not suitable.

5. A hydrometer floats higher in liquid P than in liquid Q. The better conclusion is that

6. Water flows horizontally through a pipe of area at speed . The pipe narrows to . If and viscosity is neglected, the pressure drop from the wide section to the narrow section is

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

8. A graph of viscous drag versus speed for a small sphere in the Stokes-law range is a straight line. If the slope is made larger by using another liquid, the new liquid has

9. Pressure is introduced in fluid mechanics as

10. A hydraulic jack has a small piston of area and a large piston of area . What input force is needed to lift a load of , ignoring losses?

11. In pipe flow, increasing the pipe diameter while keeping , , and unchanged makes Reynolds number

12. In a liquid at rest, pressure at a point is said to be isotropic. This means that pressure

13. A liquid surface in a vessel at rest is normally horizontal because otherwise

14. A hydraulic press has and . A force is applied on the small piston. If the small piston moves , the output force and output displacement are

15. The SI unit of surface tension is

16. A block has density , while water has density . The relative density of the block is

17. A pipe carries water steadily. At one section, and . At another section, the area is . The speed is

18. A pressure gauge reads zero when exposed to open air. This happens because the gauge

19. A small liquid drop has greater excess pressure than a large drop of the same liquid because the smaller drop has

20. In a clean glass capillary, water rises but mercury is depressed. This difference is most directly connected with

21. A horizontal Venturi meter has wide-section area and throat area . Water speed in the wide section is . Taking , the pressure difference is

22. Study the table and identify the row that gives the best surface-tension explanation.

23. Two liquids P and Q occupy equal volumes in identical containers. Liquid P has twice the mass of liquid Q. Compared with liquid Q, the density of liquid P is

24. Use the graph description below.

The correct relationship between and is

25. A U-tube manometer contains oil of density . A pressure difference of is applied between the two arms. Taking , the level difference is

26. A graph of gauge pressure versus depth is drawn for two liquids at the same place. Line X is steeper than line Y. The correct conclusion is that

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

28. Study the table and identify the row that is not matched properly.

29. A graph is drawn between gauge pressure and depth for a liquid at rest. The straight-line graph passes through the origin. Its slope is

30. A real liquid is compared with an ideal liquid. The property neglected in an ideal non-viscous liquid is

31. 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.

32. A soap bubble of radius is expanded slowly to radius . If surface tension remains constant, the increase in surface energy of the bubble is

33. The pressure inside a small liquid drop is greater than the pressure outside mainly because of

34. A liquid surface has surface tension . The force acting along a line of length on the surface is

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

36. Torricelli’s theorem is often compared with free fall because the efflux speed from depth is equal to the speed gained by a body falling freely through

37. At a liquid’s critical temperature, surface tension becomes zero because

38. A wire frame experiment increases a liquid film’s surface area by . If the liquid has surface tension , the work done against surface tension is

39. A block is suspended from a string and fully immersed in a liquid. If the block is at rest, the tension in the string is

40. Study the table and identify the row that is incorrectly matched.

41. A large tank has a small hole at depth . If the free surface is also moving downward with speed , Bernoulli’s equation gives the jet speed from the hole as

42. Two liquid drops of the same liquid have radii and . The ratio of excess pressures in the smaller drop and the larger drop is

43. A solid object floats in a liquid when its average density is

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

45. A strong wind blows over the roof of a house. The pressure above the roof may become lower than the pressure inside the house mainly because

46. A student compares four formula uses in mechanical properties of fluids.

Which row contains the unsuitable formula use?

47. Consider the following statements about the symbols used at the start of fluid mechanics.
Statement I: commonly denotes pressure.
Statement II: commonly denotes density.
Statement III: commonly denotes the speed of fluid flow.

48. A closed-end manometer has a near-vacuum above the liquid in the closed arm. If the pressure of a gas connected to the other arm supports a liquid column difference , the gas pressure is approximately

49. A final comparison is made among pressure, viscosity, and surface tension. Which statement keeps the three ideas correctly separated?

50. A soap bubble is formed from a liquid of surface tension . If its radius is , the work needed to form the bubble from an initially negligible film area is