Study sheet: Waves Physics Practice Assessment

📋 Course Outline

1. Wave Types and Properties
2. Sound Wave Behaviour
3. Reflection Refraction and Diffraction
4. Wave Equations and Calculations
5. Electromagnetic Spectrum and Imaging
6. Ultrasound Applications and Impacts

📖 1. Wave Types and Properties

🔑 Key Concepts & Definitions

• Amplitude : the maximum displacement of a particle from its equilibrium position in a wave
• Wavelength : the distance between corresponding points on successive waves, such as crest to crest or compression to compression

★ Must-know

📌 Transverse waves have particle vibrations perpendicular to the direction in which the wave travels, whereas longitudinal waves have particle vibrations parallel to the direction of travel.

Further detail

• Examples of transverse waves and longitudinal waves must be distinguished according to whether their particle vibrations are perpendicular or parallel to the direction of wave travel.

• Crests and troughs are features of transverse waves, while compressions and rarefactions are features of longitudinal waves.

💡 Memory Hook

Transverse vibrations are perpendicular to travel, whereas longitudinal vibrations are parallel.

📖 2. Sound Wave Behaviour

🔑 Key Concepts & Definitions

• Frequency : the number of complete waves or vibrations passing a point per unit time
• Period : the time taken for one complete wave or vibration

📝 Essential Points

• Sound travels through vibrations passed between particles in a medium, so sound cannot travel through a vacuum where no particles are available.

📌 Pitch depends on frequency, whereas loudness depends on amplitude.

💡 Memory Hook

Greater frequency causes higher pitch, while greater amplitude causes louder sound.

📖 3. Reflection Refraction and Diffraction

🔑 Key Concepts & Definitions

• Normal : an imaginary line drawn perpendicular to a reflecting or refracting surface at the point where the wave meets it

★ Must-know

📌 The law of reflection states that the angle of incidence equals the angle of reflection, with both angles measured from the normal.

📌 Refraction changes a wave's speed and wavelength when the wave enters a different medium, but its frequency remains unchanged.

• Diffraction is the spreading of waves through gaps or around obstacles, and it is greatest when the gap size is comparable to the wavelength.

Further detail

• An echo is a reflected sound heard after the original sound because the sound wave travels to a surface and returns.

💡 Memory Hook

Reflection bounces, refraction bends, and diffraction spreads.

📖 4. Wave Equations and Calculations

★ Must-know

📐 Formula — Wave speed is calculated using $v=f\lambda$, where speed is measured in metres per second, frequency in hertz, and wavelength in metres.

📐 Formula — Frequency and period are related by $f=\frac{1}{T}$, where frequency is in hertz and period is in seconds.

📐 Formula — The distance to a reflecting surface in an echo calculation is found using $d=\frac{vt}{2}$ because the measured time includes the journey to the surface and back.

Further detail

📐 Formula — Frequency can be calculated from the number of cycles and the time using $f=\frac{N}{t}$.

📌 Wave calculations require consistent units, including metres for wavelength or distance, seconds for time or period, hertz for frequency, and metres per second for speed.

💡 Memory Hook

VFT: speed uses frequency and wavelength; frequency uses period or cycle count.

📖 5. Electromagnetic Spectrum and Imaging

★ Must-know

• The seven electromagnetic spectrum regions in order are:
  • radio
  • microwave
  • infrared
  • visible
  • ultraviolet
  • X-ray
  • gamma

📌 All electromagnetic waves can travel through a vacuum, and across the spectrum increasing frequency corresponds to increasing energy and decreasing wavelength.

• Ultrasound scans use high-frequency sound waves to produce images, X-rays are used for imaging internal structures, SONAR uses sound echoes to detect or measure underwater objects, and thermal imaging detects infrared radiation associated with temperature.

Further detail

• Electromagnetic spectrum regions have different uses and hazards, so applications must be matched to the properties and potential risks of each region.

💡 Memory Hook

Radio, microwave, infrared, visible, ultraviolet, X-ray, gamma.

📖 6. Ultrasound Applications and Impacts

★ Must-know

• Ultrasound has medical uses such as scanning and industrial uses such as detecting internal flaws or measuring structures.

📌 Benefits of ultrasound include non-invasive imaging and practical inspection, while limitations can include restricted image quality or difficulty examining some structures.

📌 Evaluating ultrasound requires scientific reasoning about possible risks as well as benefits, limitations, and the evidence supporting each claim.

Further detail

• Ultrasound applications can have social, environmental, economic, and ethical impacts that should be considered alongside their scientific effectiveness.

• 🔄 A scientific evaluation of ultrasound should:

  1. identify benefits and limitations
  2. explain them using wave or imaging principles
  3. consider possible risks
  4. reach a justified conclusion

💡 Memory Hook

Ultrasound offers medical and industrial benefits but also has limitations, risks, and ethical impacts.