Mechanical Properties of Fluids Mock Test – Class 11 Physics

1. A graph is plotted between capillary rise and for the same wetting liquid in clean capillary tubes. The graph is a straight line through the origin. Its slope is

2. A tank of volume is filled by a pipe delivering water at . The time required to fill the tank is

3. Use the case below and answer the question.

The correct density order is

4. Archimedes’ principle states that the buoyant force on a body immersed in a fluid is equal to

5. A liquid of density flows steadily through a section of area at speed . The mass flow rate is

6. A liquid surface is increased by , and the work done against surface tension is . The surface tension is

7. The dimensional formula of pressure is

8. In fluid mechanics, liquids and gases are grouped together because both

9. The free surface of a liquid tends to behave like a stretched membrane because of

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

11. Two soap bubbles of the same liquid have radii and . They are connected by a narrow tube. Air tends to flow

12. A liquid drop of radius has excess pressure . If its surface tension is doubled while its radius is also doubled, the new excess pressure is

13. Study the table and identify the row that gives the most suitable first meaning.

14. A water tank open to air has . At one point, the absolute pressure is . Taking and , the depth of the point is

15. Two vessels contain water to the same height. Vessel P has base area , while vessel Q has base area . The gauge pressure at the base and the force on the base satisfy

16. Water flows steadily from a lower section P to a higher section Q of a pipe. At P, , , and . At Q, , and . Taking and , the pressure is

17. In a liquid at rest, two points lie in the same horizontal level. If the liquid is connected and has uniform density, the pressures at the two points are

18. A small piston of area is pushed with a force of . It is connected by an enclosed liquid to a large piston of area . Ignoring losses and height difference, the force on the large piston is

19. Two identical blocks are fully immersed separately, one in water and one in a liquid of relative density . If the buoyant force in water is , the buoyant force in the other liquid is

20. A liquid drop and a soap bubble have the same radius and the same surface tension . The ratio of excess pressure in the liquid drop to that in the soap bubble is

21. A curved ball in air can experience a sideways force when spinning. At a basic-level explanation, this is because spin can make air speed different on opposite sides, producing

22. A spring balance reads less when a metal block is dipped in water than when it is in air. The best reason is that

23. A student says, “A hydraulic press multiplies force because it creates energy inside the liquid.” The correct correction is that the press

24. A Pitot arrangement in water gives a pressure difference of . If , the flow speed is

25. In applying to a liquid emerging from a tank, represents the

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

27. The capillary rise or depression in a tube of radius is given by

28. Match the Bernoulli terms with their usual meanings.

29. A small sphere falls through a viscous liquid. At a certain instant before terminal velocity, its speed is increasing. Which force comparison is correct?

30. A liquid flows through a capillary tube under laminar conditions. If another liquid of twice the viscosity is used with the same tube and same pressure difference, the flow rate becomes

31. Use the arrangement described below.

If the containers are at rest and is the same, the gauge pressures at P, Q, and R are

32. 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

33. A barometer is taken from sea level to a high mountain. The mercury column becomes shorter. The best explanation is that

34. A vessel contains two immiscible liquids at rest. Oil of density and height floats above water of density and height . Taking , the gauge pressure at the bottom is

35. A student uses for a water droplet in air. The main error is that this formula is for

36. A horizontal ideal-flow tube has equal cross-sectional areas at two points P and Q, but the pressure at P is greater than at Q. The most reasonable conclusion from Bernoulli’s equation is that

37. A U-tube manometer is connected across the wide section and throat of a horizontal Venturi tube. The flowing liquid has density , and the denser manometer liquid has density . The pressure taps are at the same horizontal level, and the manometer level difference is . The pressure difference between the two sections is

38. Study the table and identify the row that gives the most suitable explanation.

39. Consider the following statements about impurities and temperature effects on surface tension.
Statement I: Detergents generally reduce the surface tension of water.
Statement II: Increasing temperature generally decreases the surface tension of most liquids.
Statement III: Surface tension becomes zero near the critical temperature.

40. The role of density in many fluid-mechanics formulas is best shown by the fact that a denser fluid generally

41. A rectangular vertical gate is wide and holds water to a depth of . Take and . The force on the gate due to gauge pressure is

42. A capillary tube has length . If its length is doubled while radius, pressure difference, and viscosity remain unchanged, the flow rate becomes

43. A metal sphere is completely submerged in a liquid and held at rest by a string. The buoyant force on the sphere is directed

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

45. A flow has in a pipe. The most likely flow regime is

46. A soap bubble has radius and surface tension . The excess pressure inside the bubble is

47. Surface tension arises in a liquid mainly because molecules at the free surface experience

48. Study the table and identify the row that correctly describes terminal velocity.

49. A capillary tube carrying a viscous liquid has its radius doubled while , , and remain unchanged. According to Poiseuille’s law, the flow rate becomes

50. A student calculates force on a vertical wall by multiplying the bottom pressure by the whole wall area. This gives an overestimate because