🌊 Waves (Chapter–14)
Complete Notes for Students
1. Wave Motion
Wave motion is the transfer of energy without transfer of matter.
Wave carries energy, not particles.
---
2. Types of Waves
(A) Transverse Waves
- Particles vibrate perpendicular to direction of wave
- Example: Light waves, water waves
(B) Longitudinal Waves
- Particles vibrate parallel to direction of wave
- Example: Sound waves
3. Speed of Travelling Wave
v = fλ
- v = velocity
- f = frequency
- λ = wavelength
4. Progressive Wave Equation
y = A sin(ωt − kx)
- A = amplitude
- ω = angular frequency
- k = wave number
5. Principle of Superposition
When two waves overlap, resultant displacement is sum of individual displacements.
---6. Reflection of Waves
- Wave bounces back from boundary
- Follows laws of reflection
7. Standing Waves
Formed by superposition of two waves travelling in opposite directions.
- Nodes: Zero displacement
- Antinodes: Maximum displacement
8. Waves in Strings
v = √(T/μ)
- T = tension
- μ = mass per unit length
9. Organ Pipes
Open Pipe
f = nv / 2L
Closed Pipe
f = nv / 4L (n = odd)
---
10. Fundamental Mode & Harmonics
- Fundamental: Lowest frequency
- Harmonics: Multiples of fundamental frequency
11. Beats
Variation in intensity due to interference of two waves of slightly different frequencies.
Beat frequency = |f₁ − f₂|
---
12. Important Points
- Wave transfers energy, not matter
- v = fλ is fundamental relation
- Standing waves form nodes and antinodes
- Closed pipe produces only odd harmonics
- Beats used in tuning instruments
