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C. Johannesson I. Waves & Particles Electrons in Atoms.

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Presentation on theme: "C. Johannesson I. Waves & Particles Electrons in Atoms."— Presentation transcript:

1 C. Johannesson I. Waves & Particles Electrons in Atoms

2 C. Johannesson A. Waves zWavelength ( ) - length of one complete wave zFrequency ( ) - # of waves that pass a point during a certain time period yhertz (Hz) = 1/s zAmplitude (A) - distance from the origin to the trough or crest

3 C. Johannesson A. Waves A greater amplitude (intensity) greater frequency (color) crest origin trough A

4 C. Johannesson B. EM Spectrum LOWENERGYLOWENERGY HIGHENERGYHIGHENERGY

5 C. Johannesson B. EM Spectrum LOWENERGYLOWENERGY HIGHENERGYHIGHENERGY ROYG.BIV redorangeyellowgreenblueindigoviolet

6 C. Johannesson B. EM Spectrum zFrequency & wavelength are inversely proportional c = c:speed of light ( m/s) :wavelength (m, nm, etc.) :frequency (Hz)

7 C. Johannesson B. EM Spectrum GIVEN: = ? = 434 nm = m c = m/s WORK : = c = m/s m = Hz zEX: Find the frequency of a photon with a wavelength of 434 nm.

8 C. Johannesson C. Quantum Theory zPlanck (1900) yObserved - emission of light from hot objects yConcluded - energy is emitted in small, specific amounts (quanta) yQuantum - minimum amount of energy change

9 C. Johannesson C. Quantum Theory zPlanck (1900) vs. Classical TheoryQuantum Theory

10 C. Johannesson C. Quantum Theory zEinstein (1905) yObserved - photoelectric effect

11 C. Johannesson C. Quantum Theory zEinstein (1905) yConcluded - light has properties of both waves and particles wave-particle duality yPhoton - particle of light that carries a quantum of energy

12 C. Johannesson C. Quantum Theory E:energy (J, joules) h:Plancks constant ( J·s) :frequency (Hz) E = h zThe energy of a photon is proportional to its frequency.

13 C. Johannesson C. Quantum Theory GIVEN: E = ? = Hz h = J·s WORK : E = h E = ( J·s ) ( Hz ) E = J zEX: Find the energy of a red photon with a frequency of Hz.


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