What is a wave?
- A wave is a means of transferring energy through a medium, without any net movement of that medium.
- Transverse wave: A wave where the direction of vibration is perpendicular to the direction in which the wave travels. e.g. light, waves on a rope, water waves.
- Longitudinal wave: A wave where the direction of vibration is para;;e; to the direction in which the wave travels. e.g sound, compression waves on a spring.
- Frequency: The frequency (f) is the number of cycles completed at any one point per second.
- Period: A period of a wave (T) is the time taken to undergo one complete cycle.
- Diffraction: Diffraction is the ability of a wave to recover after meeting an obstacle.
- Interference occurs when two waves meet. When this happens, the total displacement will be equal to the algebraic sum of the individual displacements. (All types of waves will undergo interference).
- Constructive interference occurs when waves from two sources meet and the amplitude of the resulting wave is greater than the amplitudes of each of the individual waves.
- Destructive interference occurs when waves from two sources meet and the amplitude of the resulting wave is less than the amplitude of each individual waves
- Coherent waves: two waves that have the same frequency and wavelength.
- Interference pattern: When waves from two or more coherent sources meet, the resulting wave pattern formed is called an interference pattern.
Stationary (standing) waves
- A stationary wave or a standing wave is produced when two waves of the same frequency and amplitude meet, moving in opposite directions.
The Doppler effect
- The Doppler effect is the apparent change in the frequency of the waves due to the motion of the source of the wave or an observer.