9.1 Properties of Waves & Light Notes PDF

# 9.1 Properties of Waves & Light - Wave - Moving disturbance that transports energy from one place to another. - Periodic wave - A wave that repeats itself at regular intervals. - Wave front - The front edge of a wave crest. ## Wave Terms - **Wavelength (λ)** - The distance between two similar p...

# 9.1 Properties of Waves & Light - Wave - Moving disturbance that transports energy from one place to another. - Periodic wave - A wave that repeats itself at regular intervals. - Wave front - The front edge of a wave crest. ## Wave Terms - **Wavelength (λ)** - The distance between two similar points in successive cycles in a wave - **Amplitude (A)** – The maximum displacement of a wave from its equilibrium point. - **Phase** - The offset of the wave from a reference point. > Waves can also interfere: > - destructive (out of phase) > - Constructive (in phase) > - Add the amplitudes for resulting wave. - **Frequency (f)** – The number of complete cycles that occur in 1 s (measured in Hz = 1/s). > $f = \frac{\#cycles}{Δt}$ infinite sig. figs. (Counted value) - **Period (T)** - The time for a vibrating particle to complete one cycle (s). > $T = \frac{Δt}{\#cycles}$ ## The Universal Wave Equation - Wave speed (v) – The rate at which a wave is travelling through a medium. > $v = fλ$ > where, >> - $v = speed (m/s)$ >> - $λ = wavelength (m)$ >> - $f = frequency (Hz or 1/s)$ > - Speed and wavelength, and speed, and frequency are directly proportional. > - Wavelength and frequency are inversely proportional. ## Reflection - **Ray approximation** - Treating the distribution of light waves as though they move in straight lines called rays. - **Reflection** - A change in direction of a light ray when it meets an obstacle where the incoming ray and the outgoing ray are on the same side of the obstacle. - **Normal** - the line drawn at a right angle to the boundary at the point where an incident ray strikes the boundary. - **Angle of incidence** - The angle between the incident ray and the normal. - **Angle of reflection** - The angle between the reflected ray and the normal. - **Law of Reflection** > For reflection from a flat surface, the angle of incidence is always equal to the angle of reflection. - **Specular reflection** – The reflection of light from a flat surface where all the reflected rays are in the same direction. - **Diffuse reflection** - The reflection of light from a surface where all the reflected rays are directed in many different directions.