Chapter 8 Notes | Physics 1st Year

“Waves”

Index:

1. Waves
2. Matter Waves
3. Progressive Waves
4. Transverse Waves
5. Longitudinal Waves
6. Periodic Waves
7. Transverse Periodic Waves
8. Equation of Wave Speed
9. Speed of Sound in Air
10. Laplace’s Correction
11. Effect of Pressure on Velocity of Sound
12. Effect of Density
13. Effect of temperature
14. Principle of Superposition
15. Interference
16. Beats
17. Reflection of Waves
18. Stationary Waves
19. Stationary Waves in a Stretched String
20. Doppler’s Effect
21. Applications of Doppler’s Effect

 Key Points:

1. Waves carry energy and this energy is carried out by a disturbance, which spreads out from the source.
2. If the particles of the medium vibrate perpendicular to the direction of propagation of the wave, then such wave is called transverse wave , e.g light waves.
3. If the particle of medium vibrate parallel to the direction of propagation of the wave, then such wave is called longitudinal wave, e.g sound wave
4. If a particle of the medium is simultaneously acted upon by two waves, then the resultant displacement of the particle is the algebraic sum of their individual displacements. this is called principle of superposition.
5. When two waves meet each other in a medium then at some points they reinforce the effect of each other and at some other points they cancel each ohter’s effect This phenomenon is called interference,
6. The periodic variations of sound between maximum and minimum loudness are called beats.
7. Stationary waves are produced in a medium, when two identical waves travelling in opposite directions interfere in that medium.
8. The apparent change in the pitch of sound caused by the relative motion of either the source of sound or the listener is called Doppler effect.