Study Notes
Waves transfer energy from one place to another without transferring matter. They are oscillations or vibrations about a fixed point, such as vibrations in ropes and springs or water waves in a pond.
- Wavefront — An imaginary surface representing the vibrating part of a wave. Example: The peak of a wave.
- Wave Speed — The rate at which energy moves through a medium, calculated as frequency multiplied by wavelength (v = fλ). Example: Measured in metres per second (m/s).
- Amplitude — The maximum displacement shown by particles in wave motion. Example: Measured in metres (m).
- Wavelength — The distance between two consecutive points in the same state of motion. Example: Measured in metres (m).
- Frequency — The number of oscillations per unit time. Example: Measured in Hertz (Hz).
- Transverse Waves — Waves where displacement is perpendicular to the direction of propagation. Example: Ripples on water, electromagnetic waves.
- Longitudinal Waves — Waves where displacement is parallel to the direction of propagation. Example: Sound waves, P-waves.
Exam Tips
Key Definitions to Remember
- Wavefront: An imaginary surface representing the vibrating part of a wave.
- Wave Speed: Calculated as frequency multiplied by wavelength (v = fλ).
- Amplitude: Maximum displacement in wave motion.
- Wavelength: Distance between two consecutive points in the same state of motion.
- Frequency: Number of oscillations per unit time.
Common Confusions
- Confusing wave speed with frequency or wavelength.
- Mixing up transverse and longitudinal waves.
Typical Exam Questions
- What is the wavelength of sound waves with a frequency of 264Hz and speed of 330m/s? Use v = fλ to find the wavelength.
- How does the wavelength change when light enters water from air? The wavelength decreases, but frequency remains the same.
- How can the speed of ripples in a ripple tank be changed? By altering the frequency of the motor.
What Examiners Usually Test
- Understanding of wave properties and equations.
- Ability to distinguish between transverse and longitudinal waves.
- Application of wave concepts to real-world examples like ripple tanks.