Chapter 15
This presentation is the property of its rightful owner.
Sponsored Links
1 / 36

Chapter 15 PowerPoint PPT Presentation


  • 131 Views
  • Uploaded on
  • Presentation posted in: General

Chapter 15. Wave Motion. Section 15-1: Simple Wave Motion Transverse and Longitudinal Waves A transverse wave. The oscillation of a transverse wave is perpendicular to the wave motion. A longitudinal wave. The oscillation of a spring is parallel to the motion . Wave pulses

Download Presentation

Chapter 15

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Chapter 15

Chapter 15

  • Wave Motion


Chapter 15

Section 15-1: Simple Wave Motion

Transverse and Longitudinal Waves

A transverse wave


Chapter 15

The oscillation of a transverse wave is perpendicular to the wave motion.


Chapter 15

A longitudinal wave

The oscillation of a spring is parallel to the motion


Chapter 15

Wave pulses

A wave pulse is a travelling disturbance.


Chapter 15

The speed of waves

The speed of a wave is a property of the medium in which it travels.

In a stretched string v= (F/μ)½

In a fluid v= (B/ρ)½

And in a gas v=(γRT/M)½

The are called the dispersion relations for the media.


Chapter 15

The derivation of v for waves on a string


Chapter 15

The Wave Equation

ð2y/ðx2 = (1/v2) ð2y/ðt2

Here y represents the vertical displacement of the string. It is called the wave function


Chapter 15

Section 15-2: Harmonic Waves

Harmonic waves on a string have a wave function of the form y=Asin(kx-ωt+φ).


Chapter 15

The Energy of Waves on a String


Chapter 15

Harmonic Sound Waves

Sound waves have a wave

function of the form:

s=s0sin(kx-ωt) where s

represents the horizontal

displacement of the wave.

The Energy of Sound Waves


Chapter 15

Electromagnetic Waves: These will be studied in Phy 2049

Section 15-3: Waves in Three Dimensions

Circular wavefronts


Chapter 15

Sound waves from a telephone handset.


Chapter 15

At a great distance from the source, spherical wavefronts look like parallel planes called plane waves


Chapter 15

A two dimensional analog to plane waves


Chapter 15

Wave Intensity

Wave intensity is the radiated power per unit area of the wavefront.


Chapter 15

Intensity Level and Loudness: This would be equivalent to brightness in a light wave.

β = 10 log (I/I0) in decibels (dB). I0 is the threshold of hearing= 1x10-12 watts/m2

Section 15-4: Waves Encountering Barriers

Reflection and Refraction: Reflection is the “bouncing” of a wave incident on an interface, back into the same medium


Chapter 15

Refraction is the “bending” of the path of a light ray as it travels from one medium into another. This is due to a difference in wave speed between the two media.


Chapter 15

Total Internal Reflection is when an incident ray is totally internally reflected. This occurs when the angle of incidence is a critical value.


Chapter 15

A wave from a light string encountering a heavier string (for which the speed is lower) suffers a phase change of π upon reflection.


Chapter 15

A wave from a heavy string encountering a lighter string (for which the speed is higher) suffers no phase change.


Chapter 15

Tunneling is when a wave penetrates through a barrier.


Chapter 15

Diffraction: The ability of a wave to move around an obstacle in its path.

Waves in a ripple tank encountering a wall with a slit. If the slit width is small compared to λ, the waves move in around the barrier and the slit becomes a point source.


Chapter 15

If the slit width is large compared to λ, there is very little diffraction.


Chapter 15

Transmitted waves radiate widely as they pass through a slit. The slit acts as a point source.

Transmitted particles are confined to narrow angle.


Chapter 15

Sound waves can give images, just like light.


Chapter 15

Section 15-5: The Doppler Effect

The Doppler Effect is a shift in frequency of a wave when there relative motion between the source and the observer. The shift is toward higher frequencies (shorter wavelengths) when the source and observer are approaching, and to lower frequencies (longer wavelengths) when they are receding.


Chapter 15

Shock Waves

When the source is traveling faster than the speed of the sound wave in the medium, shock waves result when the waves interfere with each other.


Chapter 15

This is the reason for the “sonic boom” produced by jets that exceed the sound barrier.


Chapter 15

This is “bow shock”.


Chapter 15

When applied to electromagnetic waves, this is called the Cerenkov Effect.


  • Login