WAVE PROPERTIES waves transmit energy There are two types of waves Transverse Longitudinal

Transverse Waves

Compression Waves/Longitudinal Waves

Frequency: The number of times the wavelength occurs in one second Frequency: The number of times the wavelength occurs in one second. Measured in kilohertz (Khz), or cycles per second. The faster the sound source vibrates, the higher the frequency. Higher frequencies are interpreted as a higher pitch. For example, when you sing in a high-pitched voice you are forcing your vocal chords to vibrate quickly.

Amplitude: The strength or power of a wave signal Amplitude: The strength or power of a wave signal. The "height" of a wave when viewed as a graph Higher amplitudes are interpreted as a higher volume - hence the name "amplifier" for a device which increases amplitude . Sine wave

Period, Frequency

Wavelength: The distance between any point on a wave and the equivalent point on the next phase. Literally, the length of the wave.

How are frequency and wavelength related? Electromagnetic waves always travel at the same speed (299,792 km per second). This is one of their defining characteristics. In the electromagnetic spectrum there are many different types of waves with varying frequencies and wavelengths. They are all related by one important equation: Any electromagnetic wave's frequency multiplied by its wavelength equals the speed of light. FREQUENCY OF OSCILLATION x WAVELENGTH = SPEED OF LIGHT

Off a plane surface : Note direction of propagation gets reversed. This is based on angle of incidence = angle of reflectionθ₁ = θ₂

What happens when a light wave hits glass? Some is always reflected

light going from glass to air Refraction Occurs when a wave passes from one region to another where it moves at a different speed e.g. light going from air to glass light going from air to water light going from glass to air water waves going from deep to shallow sound waves going from air to solid

At the interface, the frequency will be the same on both sides and v₁ = f λ₁ v₂ = f λ₂ Hence the refracted wave will have a shorter wavelength Obviously λ₁ = v₁ λ₂ v₂

Note that the refracted wave is bent since the wavelength is decreased so obviously λ₂ = n₁λ₁ n₂ This gives rise to Snell's law, when the wave hits the interface at an angle

Wave is incident at θ₁. Refracted wave is at θ₂, what is the relation between θ₁ and θ₂?λ₁ = d sin(θ₁) λ₂ = d sin(θ₂) and n₁λ₁ = n₂ λ₂ giving n₁ sin(θ₁) = n₂ sin(θ₂)

Incident Wave – The wave that strikes a boundary Reflected Wave – The remaining energy not transferred from the incident wave that is reflected back.

Wave pulse travelling on a string

Reflection from a HARD boundary

Reflection from a SOFT boundary

From high speed to low speed (low density to high density)

From low speed to high speed (high density to low density)

http://www.kettering.edu/~drussell/Demos/reflect/reflect.html http://www.physics.carleton.ca/~watson/1000_level/Waves_and_Optics/1004_waves.html