PHY2048_chapter16

# PHY2048_chapter16 - Chapter 16 Waves I In this chapter we...

This preview shows pages 1–5. Sign up to view the full content.

Chapter 16 Waves I In this chapter we will start the discussion on wave phenomena. We will study the following topics: Types of waves Amplitude, phase, frequency, period, propagation speed of a wave Mechanical waves propagating along a stretched string Wave equation Principle of superposition of waves Wave interference Standing waves, resonance (16 – 1)

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
A wave is defined as a disturbance that is self-sustained and propagates in space with a constant speed Waves can be classified in the following three categories: 1. Mechanical waves. These involve motions that are governed by Newton’s laws and can exist only within a material medium such as air, water, rock, etc. Common examples are: sound waves, seismic waves, etc. 2. Electromagnetic waves. These waves involve propagating disturbances in the electric and magnetic field governed by Maxwell’s equations. They do not require a material medium in which to propagate but they travel through vacuum. Common examples are: radio waves of all types, visible, infra-red, and ultra- violet light, x-rays, gamma rays. All electromagnetic waves propagate in vacuum with the same speed c = 300,000 km/s 3. Matter waves. All microscopic particles such as electrons, protons, neutrons, atoms etc have a wave associated with them governed by Schroedinger’s equation. (16 – 2)
Waves can be divided into the following two categories depending on the orientation of the disturbance with respect to the wave propagation velocity . If the disturba v Transverse and Longitudinal waves r nce associated with a particular wave is perpendicular to the wave propagation velocity, this wave is called " ". An example is given in the upper figure which depicts a mechanical wave that transverse propagates along a string. The movement of each particle on the string is along the -axis; the wave itself propagates along the -axis. y x A wave in which the associated disturbance is parallel to the wave propagation velocity is known as a " ". An example of such a wave is given in the lower figure. It is produced by a p lonitudinal wave iston oscillating in a tube filled with air. The resulting wave involves movement of the air molecules along the axis of the tube which is also the direction of the wave propagation velocity . v r (16 – 3)

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
Consider the transverse wave propagating along the string as shown in the figure. The position of any point on the string can be described by a function ( , ). Further along the chapter we shall s y h x t = ( 29 ee that function has to have a specific form to describe a wave. Once such suitable function is: ( , ) sin - Such m h y x t y kx t ϖ = a wave which is described by a sine (or a cosine) function is known as " ". The various terms that appear in the expression for a harmonic waveare identified in the lower figure Function ( y x harmonic wave ( 29 , ) depends on and . There are two ways to visualize it. The first is to "freeze" time (i.e. set ). This is like taking a snapshot of the wave at . , The second is to set .
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern