Homework
- Ex 3D, p.66--67, Wave Properties
- Ex 3E, p.69-70, Diffration
- Ex 3F, p.3F, p.73-75 Superposition
Basic Properties of Waves
waves transfer energy through a medium without transferring the medium itself
- Cycle - a basic repeating unit in a wave
- Amplitude A (m) - the distance from the middle point to the top of a crest, or bottom of a trough
- Wavelength 𝜆 (m) - the distance/length of one cycle
- Period T (s = s per cycle) - the time it takes for one cycle to pass a point
- Frequency f (Hz = cycles per second) - the number of cycles that pass in one second
T = 1/f & f = 1/T
- Wave Speed v (ms-1) the speed of a wave
v = 𝜆/T & v = f𝜆
Wave Properties
Frequency & Period
Wave Phase
Pendulum Waves
Longitudinal Waves
particle displacement in the medium is parallel to the direction of wave propagation e.g. sound waves, primary earthquake waves
Transverse Waves
particle displacement in the medium is perpendicular to the direction of wave propagation e.g. light and other electromagnetic waves, secondary earthquake waves
- Superposition of Waves: two waves traveling through each other will not change each other motion in any way, but they will add to one another when they overlap
- Constructive Interference - Reinforcement - In Phase
- Destructive Interference - Cancellation - Out of Phase
Reflection on A String
Hard Boundary
Wave reflects on opposite side (opposite phase)
Same Amplitude, A
Same Wavelength, 𝛌
Same Wave Speed, v
Reflection on A String
Soft Boundary
Wave reflects on same side (same phase)
Same Amplitude, A
Same Wavelength, 𝛌
Same Wave Speed, v
Refraction on A String
Fast to Slow Boundary
Relation of waves to Incident Wave
Reflected Wave - same speed - same wavelength 𝛌 - opposite phase
Refracted Wave - slower speed - smaller wavelength 𝛌 - same phase
Refraction on A String
Slow to Fast Boundary
Relation of waves to Incident Wave
Reflected Wave - same speed - same wavelength 𝛌 - same phase
Refracted Wave - faster speed - larger wavelength 𝛌 - same phase
