Presentation on theme: "Physics and the Quantum Mechanical Model"— Presentation transcript:
1 Physics and the Quantum Mechanical Model Light and Atomic Spectra
2 What is Light?? What do you think light is? Can you describe it?? Isaac Newton ( ) thought of light as consisting of particles.By the year 1900, however, most scientists accepted the idea that light was a wave phenomenon.
3 Light as a WAVEAccording to the wave model, light consists of electromagnetic waves.Electromagnetic Radiation – includes radio waves, microwaves, infrared waves, visible light, ultraviolet waves, x-rays, and gamma rays.All light travels at 3.0x108m/s (or _____________)
4 The Wave Cycle Each complete wave cycle has several important parts The amplitude is the wave’s height from the origin to the crestThe wavelength (denoted “λ”) is the distance between crests.The frequency (denoted “ν”) is the number of wave cycles to pass a given point in a specified amount of time
6 Wavelength and Frequency The frequency and wavelength are inversely related… meaning as one ____________ the other ____________.As the wavelength increases, the frequency decreases.The product (multiplication) of these two values ALWAYS equals a constant (c) which is known as the ______________________.
7 Mathematical Relationship c = the speed of light (a constant), 3.0x108m/s (or 3.0x1010cm/s )λ = wavelengthν = frequency, units are cycles per second, or Hertz (Hz)
9 The Visible SpectrumWhen light passes through a prism, different wavelengths separate out into their own different colors.This phenomenal spectrum of colors can be seen in a rainbow.These colors you can see are known as the VISIBLE SPECTRUM. (ROYGBIV)
13 Atomic Emission Spectrum Each element emits light when excited with electricity while in its gas/vapor phase.The atoms become “excited” when the absorb the electrical energy, and the “relax” when that energy is then released again. This release emits a “spark” of light, unique to that particular element, known as the Atomic Emission Spectrum.
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