Wave motion and its applications

waves and its application

1. Wave Motion and Its Application

2. Wave motion is a form of disturbance which travels forward (in material medium or vacuum) due to repeated periodic motion of particles about their mean position and motion being transferred from one particle to another in direction of propagation of wave. Wave Motion

3. Mechanical or Elastic Waves: They compulsorily require material medium for propagation. For e.g. Sound Waves, Water Waves (Ripples), Waves in Strings and Ropes The medium in which mechanical waves propagate must possess inertia and elasticity (so that particle can come to its original position & shape also can transfer its energy to next particle) Types of Waves

4. Electromagnetic Waves The waves which do not require material medium for their propagation and can travel in vacuum. For e.g. Radio Waves, Microwaves, X rays. Remember Wave Motion is just the transfer of energy not te transfer of matter. Types of Waves

5. Transverse Waves are those in which particles of medium vibrate along the mean position in direction at right angles to direction of propagation of wave. E.g ripples, waves in string Transverse Waves

6. Transverse Waves are those in which particles of medium vibrate back and forth along the mean position along the direction of propagation of wave. E.g Sound Waves, Waves produced in spring Longitudinal Waves

7. Wavelength Amplitude Frequency Wave Velocity Crest Trough Compression Rarefaction Terms used in wave motion

8. Transverse Waves For detailed definition of all terms refer book.

9. Features of Longitudinal Waves Features of Transverse Waves Difference between Longitudinal and Transverse Waves Sound Waves and their properties Light Waves and their properties Numerical to be practiced on formulae v = n λ v= wave velocity, n= frequency, λ = wavelength Topics you can understand now

10. Periodic Motion: A Motion which repeats itself after certain interval of time. E.g. Pulse beat, Pendulum of clock, Rotation of earth around its axis. Oscillatory Motion: Any back and forth motion which equal intervals of time about fixed time. E.g. Vibrations of strings on musical instruments, oscillations of mass about spring. Remember every oscillatory motion is periodic but every periodic motion is not oscillatory Simple Harmonic Motion

11. A body is said to execute SHM if its acceleration is directly proportional to its displacement from a fixed point (mean position) and always directed to that point. E.g. Motion of piston of engine, Vibrations of prongs of tuning fork. SHM

12. Harmonic Oscillator: A body which executes SHM. Displacement, y: The distance travelled by vibrating particle from its mean position. Amplitude, A: Maximum displacement of particle from mean position. Time period, T: Time taken by particle to move from mean to one extreme position and back to mean position. Important Terms related to SHM

13. Frequency, n: Number of Vibrations completed by particle per second. Units Hertz, per sec. Angular velocity, ω : Rate of change of angular displacement, ϴ . Units radians/sec Phase: State of particle with respect to its mean position (means how much angle it is away from mean position) Phase Difference: The difference is phases of two particles oscillating at any instant of time.

14. SHM as projection of circular motion

15. A Progressive Wave is one which travels in a given direction in a medium with same amplitude and constant speed. Equation y = a Sin ω t y = a Sin 2 π t/T { ω = 2 π / T} Progressive Waves

16. The redistribution of energy in medium when two or more waves arrive at a point at same instant of time. Principle of Superposition of Waves: If two or more waves are moving through medium then resultant displacement at any point is algebraic sum of the displacement Superposition of Waves

17. Two waves of same frequency moving in same direction result in interference. Two waves of same frequency moving in opposite direction produce stationary waves. Two waves of slightly different frequencies moving in same direction give rise to beats. Important Cases of Superposition of Waves

18. The redistribution of energy in medium when two sound waves overlap. Interference of Waves

19. Constructive Interference: The redistribution of energy when two waves in same phase superimpose upon each other. Destructive Interference: The redistribution of energy when two waves in opposite phase superimpose upon each other. Types of Interference

20. When two identical waves travel through a medium along the same line in opposite directions, they superimpose on each other give rise to new types of waves which appear to be stationary in space. Stationary waves

21. Topics to be done Characteristics of Stationary Waves. Comparison between Progressive and Stationary Waves

22. The periodic rise and fall in the intensity or loudness of sound caused by the superposition of two sound waves of slightly different frequencies. Beats

23. Read and memorize the definitions with examples of above mentioned types of vibrations. Mathematical part of SHM will be discussed. Free, Forced & Resonant Vibrations