Waves

Define wave motion

A periodic motion repeated at regular intervals that transfers energy from one place to another without transfer of matter

*Individual particles oscillate about their fixed positions

How are waves sourced?

Vibrations or oscillations

What are transverse waves?

Waves that travel perpendicular to the direction of vibration

What are longitudinal waves?

Waves that travel parallel to the direction of vibration

What is a wavefront?

An imaginary line between 2 adjacent points of a wave

What is amplitude?

Maximum displacement moved by a point on a wave from its equilibrium position

What is wavelength?

Shortest distance between any 2 points that are in phase

*1 complete wave

What is period?

Time taken to produce 1 complete wave

What is frequency?

Number of complete waves per second

What is the crest and trough of a wave?

• Crest = maximum point

• Trough = minimum point

Formula for wave velocity

v = fλ

Formula for frequency

f = 1/T

s-t graph of a wave

s-d graph of a wave

What is wave refraction?

• When waves slow down in shallow water

• Frequency remains the same, so wavelength decreases

What does it look like when waves are refracted at an angle?

What does wave reflection look like?

What are sound waves?

Longitudinal waves created by a vibrating source that travel through collisions in particles

*Requires a medium to be transmitted

What are compressions and rarefactions in sound waves?

Rarefaction = air particles are further apart and air pressure < atm

Compression = air particles are close together and air pressure > atm

How does a property of waves change pitch?

High frequency = higher pitch

Lower frequency = lower pitch

How does a property of waves change volume of sound?

Higher amplitude = louder

Lower amplitude = softer

What are infrasound and ultrasound?

Infrasound = frequencies below the hearing limit of the human range audibility

Ultrasound = frequencies above upper limit of the human range audibility

Human range audibility = 20-20k Hz