Light as a Wave: Part 1 SNC2D
What is a wave? A wave is a disturbance which carries energy from one location to another. The material the disturbance travels through is the medium. The movement of the disturbance is referred to as propagation.
Snapshot of a Wave The dashed line represents the equilibrium position of the particles.
Snapshot of a Wave The positions of maximum displacement are referred to as crests (positive displacement) and troughs (negative). The maximum displacement is the amplitude.
Snapshot of a Wave The distance between one crest and the next crest (or one trough and the next trough) is the
Snapshot of a Wave The distance between one crest and the next crest (or one trough and the next trough) is the wavelength, represented by
Snapshot of a Wave The distance between one crest and the next crest (or one trough and the next trough) is the wavelength, represented by l.
Snapshot of a Wave The time it takes one complete wavelength to pass a single point is the
Snapshot of a Wave The time it takes one complete wavelength to pass a single point is the period, represented by
Snapshot of a Wave The time it takes one complete wavelength to pass a single point is the period, represented by T.
Snapshot of a Wave The number of complete wavelengths that pass a single point in one second is the frequency, represented by f.
Frequency Frequency is measured in units of s-1 or Hertz (Hz). “I do not think that the wireless waves I have discovered will have any practical application.”
Wave Speed The speed of a wave is therefore:
Wave Speed The speed of a wave is therefore:
Wave Speed The speed of a wave is therefore:
Wave Speed The speed of a wave is therefore: Practice Question: What is the wavelength of a wave with a speed of 344 m/s and a frequency of 256 Hz?
Wave Speed Practice Question: What is the wavelength of a wave with a speed of 344 m/s and a frequency of 256 Hz?
Wave Speed Practice Question: What is the wavelength of a wave with a speed of 344 m/s and a frequency of 256 Hz?
Wave Speed Practice Question: What is the wavelength of a wave with a speed of 344 m/s and a frequency of 256 Hz?
Light is an “EM” wave Light is actually a transverse wave
Light is an “EM” wave Light is actually a transverse wave, but the perpendicular-to-propagation disturbance is not of particles of a medium but of the electric and magnetic (EM) fields
The Speed of Light Because light waves do not need a medium, they can travel through a vacuum (empty space) and do so at the speed of light: c =
The Speed of Light Because light waves do not need a medium, they can travel through a vacuum (empty space) and do so at the speed of light: c = 3.0 x 108 m/s.
The Speed(s) of Light Light will travel slower in denser media (e.g. glass), but the speed in air is still effectively 3.0 x 108 m/s and