Physics-Topic-4


Lecture-4

Physics

1. What is the unit of Relative Density ?- There is no unit of Relative Density.

2. Which instrument measures Relative Density ?- Hydrometer

3. Why does ice float on water ?- Because density of ice is lesser than that of water.

4. What is the density of ice ? – 0.92 g /cm3

5. What is the density of water ?- 1g /cm3

6. Density of human body is _____ than that of water ?- Less

7. The density of human head is ______ than that of water ?- More

8. To make a body float on the water the weight of the displaced water by the body must be _____ the weight of the body ?-  Equal to

9. If ice floating in water in a vessel melts, the level of water in the vessel ________.- does not change.

10. The density of sea water is __________ that of normal water. – More than

11. The pressure exerted anywhere at the point of confined fluid is transmitted equally and undiminished in all directions throughout the liquid. This is ________. – Pascal Law

12. Examples of the application of the Pascal’s Law

·       Hydraulic Lift

·       Hydraulic Press

·       Hydraulic Brake

13. The upward force exered by a fluid on the immersed body is called __________. –Buoyant Force or Upthurst

14. Buoyant force depends upon the ___________.- Density of Fluid

15. When a solid body is immersed wholly or partially in a liquid , then there is some apparent loss in its weight. This loss in weight is equal to the weight of the liquid displaced by the body. It is ____________. – Archimedes Principle

16. Whenever a solid body is dipped into a fluid, the fluid exerts force of buoyancy on it, if the force of buoyancy equal to weight of the solid , the solid will remain in equilibrium. This is called ________.- Flotation

17. ________ is the force acting normally to a unit of length of an imaginary line drawn on the surface of liquid.- Surface Tension

18. What is the unit of Surface Tension ?- N/m

19. _________ is the intermolecular force of attraction acting between the molecules of the same substance. – Cohesive Force

20. _________ is the intermolecular force of attraction acting between the molecules of the different substances. – Adhesive Force

21.The surface tension _________ with the rise in temperature and become zero at the critical temperature. – Decreases

22. Due to _______ rain drops are spherical in shape.- Surface tension

23. The phenomenon of rise of depression of liquids in a capillary tube is called __________. –Capillarity

24. Example of Capillary Action :

·       Kerosene oil in a lantern .

·       Writing nib broken in the mid to have fine capillarity.

·       Water movement in plants.

25. __________ is the property of the liquid by virtue of which it opposes the relative motion between its adjacent layers. – Viscosity.

26. Viscosity in an ideal fluid is _______. –Zero

27. Viscosity is the property of ________. –Liquids and Gases

28. With the rise in temperature , viscosity of liquids __________ and that for gases ________. – decreases , increases

29. Viscosity of gases is much ______ than that of  liquids. – less

30. Viscosity of liquid _______ with increase in  pressure.-  increase

31. What is the SI Unit of viscosity ?- Pa/s

32.  When a body falls in a viscuous medium , its velocity first increases and finally becomes constant. This constant velocity is called _________. – Terminal Velocity

33. The limiting velocity of a liquid above which flow will become turbulent is called __________- Critical Velocity

34. When an incompressible and non-viscuous liquid (or gas ) flows in streamlined motion from one place to another , then at every point of its path the total energy per unit volume remains constant , it is called ________. – Bernoulli’s Theorem

35. If a body moves to and fro on a straight line about a fixed position , then its motion is called _________. – Simple Harmonic Motion

36. Any motion which repeats itself after a regular interval of time is called _________. – Periodic or harmonic motion.

37. Example of Periodic Motion :

·       Motion of hands of a Clock

·       Motion of Earth around the Sun

·       Motion of needle of Sewing Machine

38. If particle repeats its motion after a regular time intervals about a fixed point , motion is said to be _________. Oscillatory or Vibratory

39. Example of Oscillatory Motion :

·       Motion of Piston in an automobile engine.

·       Motion of Balance of Wheel on a watch.

40. A pendulum clock goes slow in _______ and  fast in ______ .-summer , winter

41. _______ is a disturbance which propagates energy from one place to the other without the transport of matter .- A wave

 42. The waves which require material medium (solid , liquid or gas ) for their propagation are called __________. –Mechanical Waves

Longitudinal and Transverse Wave

https://www.youtube.com/watch?v=0Anh9HthWgQ

43. If the particles of the medium vibrate in the direction of the propagation of wave motion , the wave is called ________. – Longitudinal Wave

44. Example of Longitudinal Waves :

·       Waves on Spring

·       Sound Waves

45. If the particle of the medium vibrates perpendicular to the direction of propagation of wave , the wave is called _______. –Transverse Waves

46. The wavelength which do not require medium for their propagation i.e. which can propagate even through the vacuum are called _________. – Electromagnetic Wave

47. Waves that are not Electromagnetic Waves :

·       Cathode Rays

·       Canal Rays

·       Alpha Rays

·       Beta Rays

48. Waves that are the examples of the Electromagnetic Waves :

·       Light Waves

·       Heat Waves

49. Maximum displacement of a vibrating particle of medium from its mean position is called _______. –Amplitude

50. The position of a point in time on wave form cycle is called _______. –Phase

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