Date post: | 28-Nov-2014 |
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Types of Waves
Waves
• A wave is a back and forth motion that carries energy through matter or through space.
Characteristics of a Wave
• The highest points on a wave are called crests.• The lowest points are called troughs.
Characteristics of a Wave
• Wavelength is the distance between one crest or trough to the next.
Characteristics of a Wave
• Amplitude is a measure of the wave’s height from the resting position.
• Amplitude is equal to one-half of the vertical distance between a crest and trough.
• Waves with larger amplitudes carry more energy.
Characteristics of a Wave
• Frequency of a wave is a count of either the number of crests or the number of troughs that pass a point in a given amount of time.
• The higher the frequency, the more energy the wave carries.
• Frequency is measured in units of hertz (Hz).• One Hz = one wave per second.
Two types of waves
• Waves are generally one of two basic types:– Mechanical – Electromagnetic
Mechanical Wave
• Mechanical waves travel through matter by creating vibrations in a medium.
• The medium can be any type of matter:– Solids– Liquids– Gases
• Examples of Mechanical waves:– Sound– Seismic waves– Water waves
Electromagnetic Waves
• Electromagnetic waves are not caused by a disturbance of particles in a medium.
• It is produced by an interaction between an electric and magnetic field.
• Examples:– X-rays– Microwaves– Radio waves– Visible light
Electromagnetic Spectrum
• An electromagnetic spectrum is a range of radiant energy arranged in order of wavelength and frequency.
Radio Waves
• Have some of the longest radio wavelengths of all electromagnetic waves. – Low energy waves.– Radio and Television stations use radio waves.
Microwaves
• Short wavelengths• High frequency• Carry more energy than radio waves• Uses:– Cell Phones– Radars– Microwave ovens
X-Rays and Gamma Rays
• X-Rays– High energy– Short wavelengths– Greater penetrating power
• Gamma Rays– More energy than X-Rays– Produced by some nuclear reactions
Other types of waves
• Infrared waves– Carry more energy than microwaves
• Visible light– Can be seen with human eye– Contains all colors of light
• Ultraviolet light– Short wavelength– Greater energy than visible light
Compressional Waves
A wave consisting of a periodic disturbance or vibration that takes place in the same direction as the advance of the wave.