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