Topic 4: Waves

Traveling Waves

Waves

1. Distinguish between oscillations and wave motion.

2. Describe a wave pulse and a continuous traveling wave.

3. Understand that there is no net motion of the medium through which the wave travels.

4. State that waves transfer energy.

5. Describe and give examples of transverse and longitudinal waves. Know that sound is a longitudinal wave and that light is a transverse wave.

6. Describe waves in two dimensions, including the concepts of wave fronts and rays.

Wave characteristics

1. Define displacement, amplitude, period, frequency, wavelength and wave

2. speed.

3. Describe the terms crest, trough, compression and rarefaction.

4. Draw and explain displacement–time and displacement–position graphs for transverse and longitudinal waves.

5. Derive and apply the relationship between wave speed, wavelength and frequency.

Wave Properties

Reflection, refraction and transmission of waves

1. Sketch incident, reflected and transmitted

2. waves, and the cases of reflection at free and fixed ends.

3. Describe the reflection and transmission of one-dimensional waves at a

4. boundary between two media.

5. State Huygens’ (Pronunciation: 'hI-g&nz) principle.

6. Apply Huygens’ principle to two-dimensional plane waves to show that the angle of incidence is equal to the angle of reflection.

7. Explain refraction using Huygens’ principle.

8. Define refractive index or index of refraction.

9. Derive, using Huygens’ principle, Snell’s law for refraction.

10. State and apply Snell’s law.

n1 sin( θ1) = n2 sin(θ2)

Wave diffraction and interference

1. Explain and discuss qualitatively, using Huygens’ principle, the diffraction of waves by apertures and obstacles.

2. Discuss the effect on diffraction and interference of wavelength compared to obstacle size or aperture size.

3. Describe examples of diffraction.

4. State the principle of superposition and explain what is meant by constructive and destructive interference (only one-dimensional situations).

5. Apply the principle of superposition to find the resultant of two waves.

Doppler effect

1. Describe the Doppler effect in simple terms for both light and sound.

Standing Waves

1. Describe the nature of standing waves.

2. Explain the formation of standing waves in one dimension.

3. Compare standing waves and traveling waves.

Boundary conditions and resonance

1. Explain the concept of resonance and state the conditions necessary for resonance to occur.

2. Note that fundamental and first harmonic are interchangeable terms.

3. Solve problems involving the fundamental and higher harmonic modes. (Note: fundamental and first harmonic are interchangeable terms. )

• stretched strings

• open pipes

• closed pipes