Waves & Sound Review Quiz #1

Wave

Wave

• A disturbance propagating through a medium.

  • Disturbance- a pattern of displacement from an equilibrium point or state

  • Propagation- self sustaining motion

Pulse

A wave generated by a single limited distance.

Continuous Wave

A wave generated by periodic disturbance.

Constructive inference

Higher amplitude

Destructive intereference

Lower amplitude

The source causes the _______________.

disturbance

The source supplies ___________.

energy

The disturbance ____________.

travels

The medium _________ travel, but oscillates about a fixed point.

doesn’t

Types of Waves

• Transverse waves

• Longitudinal waves

• Raleigh waves

• Torsional waves

Transverse Waves

Particles in the medium oscillate in SHM perpendicular to the direction in which the wave disturbance moves.

Longitudinal Waves

Particles in the medium oscillate in SHM parallel to the direction in which the wave disturbance moves.

Wavelength

Crest to crest

Trough

Lowest point/crest on graph

Crest

Highest point on graph

Amplitude

Distance from equilibrium to trough or crest.

Compression

When particles are compressed together

Rarefaction

When particles are far apart

Both transverse waves & longitudinal waves

have compressions and rarefactions

Raleigh Waves

Particles move in elliptical paths

Torsional Waves

Twisting (torque) waves

Period (T)

The time of cycles per unit time

Frequency (f)

The number of cycles per unit time

Speed (v)

The time rate of change of distance traveled by the disturbance

Speed of sound

340 m/s

Speed of light

3.0 x 10⁸ m/s

Speed of sound through steel

5000 m/s

Speed of light through diamond

2.0 x 10⁸ m/s

Wavelength (λ)

The linear distance between adjacent corresponding points of a continuous wave (distance for one complete cycle)

Amplitude (A)

The maximum level of disturbance of the medium measured from equilibrium

Unit for T (period)

seconds (s)

Unit for f (frequency)

Hertz (Hz)

Unit for v (wave speed)

meters/second (m/s)

Unit for λ (wavelength)

meters (m)

Unit for A (amplitude)

meters (mechanical waves), Joules (light), Pascals (sound)

Wave Speed, v

• v = fλ

• The rate at which the disturbance or pulse moves along the direction of travel of the wave

Wave Topics

• Properties of all waves

• Types of waves

• Wave speed (and other factors)

• Superposition & interference

• Reflection of waves

• Sound

• Doppler effect

• Standing waves

Amplitude (A), controlled by…

Source

Wavelength (λ), controlled by…

Medium

Period (T), controlled by…

Source

Frequency (f), controlled by…

Source

Speed (v), controlled by…

Medium

High tension & high frequency =

shorter wavelengths

To fully illustrate all of a wave’s parameters (A, λ, f, T, v), two graphs must be displayed:

• “History” Graph

• “Snapshot” Graph