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Unit 6  Notes Waves
Unit 6 Waves 23-1

A wave is any periodic disturbance in a material from an equilibrium state which travels from one region to another.

All waves transfer energy through matter or space.

Two major types of waves are mechanical and electromagnetic.

A medium is the matter through which a wave is transmitted.  The medium does not move along with the wave - only the energy is transmitted.

All waves have amplitude, wavelength, and frequency.

Amplitude relates to wave energy (intensity/wave height - trough, crest)

Wavelength is the distance between the same point on two successive waves.

Frequency depends on wavelength and speed.  It is the number of waves that pass a point per second.  (Measured in hertz   Hz)

Wave period = 1/frequency    ( T = 1/f )
                  (not in text)

Transverse waves: motion of the medium is at right angles to the direction of the wave.

Longitudinal waves: motion of the medium is parallel to the direction of the wave.

Wave speed  =  frequency  x  wavelength

Wave interactions: reflection, refraction, diffraction, interference (constructive or destructive) (see 24-3 for sound wave interactions)

Standing wave (resonant frequency)

Sound waves are longitudinal mechanical waves with "compressions" and "rarefactions."

Speed of sound (m/s)

Pitch relates to the frequency of a sound wave as perceived by humans.

Doppler Effect: the difference in frequency between a sound produced and that perceived by a listener who is moving relative to the source.

Electromagnetic waves are transverse waves: the direction of the wave is at right angles to both the electric and magnetic fields (p643).

EM spectrum  - energy increases with frequency.

Photon: a tiny bundle of light energy

Light behaves like a wave and a particle

Reflection of light
Refraction of light