4 PrismA Prism can be used to separate white light into the colors of the visible light spectrum.
5 Particle or wave?Light can be described as a particle, as a wave, and even as a combination of the two.Wave model is best suited for introductory discussion of light.
6 Light SpectrumThe spectrum of light is not confined to just visible light.There are many variations of light:Radio wavesMicrowavesInfrared (IR) WavesVisible LightUltraviolet (UV) LightX RaysGamma Rays
7 Electromagnetic Spectrum All of the different kinds of light are examples of electromagnetic waves.Electromagnetic Waves – A transverse wave consisting of oscillating electric and magnetic fields at right angles to each other.
8 Transverse Waves vs. Longitudinal Waves Transverse waves oscillate perpendicular to the direction of the wave propagation.Light WavesLongitudinal waves oscillate parallel to the direction of the wave propagation.Sound WavesLink:Transverse and Longitudinal Wave Animation
9 Electromagnetic Waves Light is composed of electric and magnetic waves.They are perpendicular to the direction they move.They are transverse waves.The electric and magnetic fields are at right angles to each other
10 Wave DifferencesElectromagnetic waves are distinguished by their difference in frequencies and wavelengths.They account for the color changes in visible light and distinguishes visible light from invisible electromagnetic radiation, such as X Rays.
13 Speed of LightAll forms of electromagnetic radiation travel at a single high speed in a vacuum.The speed of light in a vacuum was found to be x108 m/sc = 3.00x108 m/s (speed of light)
14 Speed of Light = frequency x wavelength Wave Speed Equationc = fλSpeed of Light = frequency x wavelengthSpeed of Light (c) – Units are in (m/s)Frequency (f) – Units are in (Hz)Wavelength (λ) – Units are in (m)
15 Example ProblemWhat is the wavelength of infrared light with a frequency of 3.0x1012 Hz?
17 Huygens' Principle The wave nature of light can be treated as a ray. Treating the propagating wave of light as a straight line perpendicular to the wave front.
18 Brightness of Light The brightness of light depends on: How much light is being emitted from the source.Distance away from the source.
19 Brightness and Distance Apparent brightness is proportional to the actual brightness of the source divided by the square of the distance between source and observer.Lv = L/d2Apparent Brightness = Actual Brightness ÷ distance2Brightness – Units (cd) “candela”