Properties of Waves | Waec Physics

Reflection of Waves

1. Reflection occurs when a wave encounters a boundary and bounces back into the original medium.
2. The angle of incidence equals the angle of reflection ($\theta_i = \theta_r$).
3. Reflection happens with both transverse and longitudinal waves.
4. Examples of reflection include echoes and light bouncing off mirrors.
5. In a ripple tank, plane waves reflect from barriers, forming distinct patterns.
6. Reflection is responsible for phenomena like standing waves in strings and air columns.
7. Smooth surfaces produce clear reflections, while rough surfaces scatter waves.
8. Reflection is vital in technologies like sonar, radar, and acoustic design.
9. The phase of reflected waves depends on the boundary properties.
10. Understanding reflection helps in designing optical and wave-based systems.
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Refraction of Waves

11. Refraction occurs when a wave passes from one medium to another and changes direction due to speed variation.
12. The angle of refraction depends on the wave's speed in the two media, governed by Snell's law: $\frac{\sin \theta_1}{\sin \theta_2} = \frac{v_1}{v_2}$.
13. Refraction bends waves toward the normal in slower media and away in faster media.
14. In a ripple tank, water waves refract when passing over regions of different depths.
15. Refraction explains phenomena like bending of light in lenses and sound wave direction changes in the atmosphere.
16. Refraction plays a role in optics, telecommunications, and acoustics.
17. Waves slow down in denser media, affecting their wavelength but not frequency.
18. Refraction causes visual distortions, such as objects appearing bent underwater.
19. The degree of refraction depends on the wave’s speed and wavelength.
20. Applications include fiber optics, eyeglasses, and seismic wave analysis.
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Diffraction of Waves

21. Diffraction occurs when waves bend around obstacles or pass through small openings.
22. The extent of diffraction depends on the size of the obstacle relative to the wavelength.
23. Longer wavelengths diffract more than shorter wavelengths.
24. In a ripple tank, plane waves passing through a gap produce curved wavefronts.
25. Diffraction explains why sound can be heard around corners, but light cannot.
26. Water waves demonstrate clear diffraction patterns in ripple tank experiments.
27. Diffraction is critical in wave-based technologies like diffraction gratings and x-ray crystallography.
28. It affects the resolution of optical and acoustic systems.
29. Diffraction is more pronounced when the gap size is comparable to the wavelength.
30. Understanding diffraction aids in designing devices like antennas and sensors.
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Interference of Waves

31. Interference occurs when two or more waves overlap, combining to form a new wave pattern.
32. Constructive interference happens when waves are in phase, amplifying the resultant wave.
33. Destructive interference occurs when waves are out of phase, reducing or canceling the resultant wave.
34. Interference patterns depend on the relative phase and amplitude of the waves.
35. In a ripple tank, two point sources create circular waves that form interference patterns.
36. Applications of interference include noise-canceling headphones and optical coatings.
37. Constructive interference increases energy transfer efficiency in wave systems.
38. Destructive interference can create quiet zones in sound waves.
39. Interference patterns reveal wave properties like wavelength and coherence.
40. Interference principles are used in designing interferometers and holography systems.
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Superposition of Waves and Standing/Stationary Waves

41. The principle of superposition states that the resultant wave is the sum of individual wave displacements.
42. Superposition explains the formation of standing waves in confined systems.
43. Standing waves form when two waves of the same frequency and amplitude travel in opposite directions.
44. Standing waves have fixed nodes (no motion) and antinodes (maximum motion).
45. In a ripple tank, standing waves appear as stationary patterns between reflected and incoming waves.
46. Standing waves are common in musical instruments, pipes, and vibrating strings.
47. The distance between two consecutive nodes or antinodes is half the wavelength.
48. Harmonics are standing waves with frequencies that are integer multiples of the fundamental frequency.
49. Standing waves demonstrate resonance, amplifying wave energy at specific frequencies.
50. Understanding standing waves is essential for acoustic engineering and wave physics.
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Ripple Tank Demonstrations

• Reflection: Place a barrier in the ripple tank to observe wave bouncing at equal angles.
• Refraction: Use a sloping glass plate to create regions of varying depth and observe wave bending.
• Diffraction: Introduce narrow slits to observe wave bending and spreading.
• Interference: Use two point sources to generate overlapping wave patterns.
• Standing Waves: Set up barriers to observe stationary wave patterns in confined areas.

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