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9 Cards in this Set
- Front
- Back
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What is the relationship between wavelength (m) and frequency (Hz)? |
λv = c where c = velocity of light = 3.00 x 10^8 ms^-1 and λ = wavelength |
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If a sodium flame emits at 589.6 nm, what is the frequency of this electromagnetic radiation? |
(nm = 1 x 10^-9) v = c/λ = 3.00 x 10^8 ms^-1 / 5.89 x 10^-7 m = 5.09 x 10^14 Hz = 5.09 THz |
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Planck: The energy of a quantum (photon) is given by the equation...? |
E = hv where h = Planck's constant, 6.63 x 10^-34 Js |
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What is the value of Planck's constant? |
6.63 x 10^-34 Js |
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Electrons and electromagnetic waves exhibit properties of both waves and particles. Suggest evidence which indicates that electromagnetic radiation has particle properties. |
The photoelectric effect - the ejection of electrons from a material on irradiation (exposure of radiation) of light. Photons carry the energy from Planck's Law with a current only flowing above a minimum frequency. |
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Electrons and electromagnetic waves exhibit properties of both waves and particles. Suggest evidence which indicates that electromagnetic radiation has wave properties. |
Interference or diffraction or refraction. |
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Electrons and electromagnetic waves exhibit properties of both waves and particles. Suggest evidence which indicates that electrons have wave properties. |
Electron diffraction. |
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De Broglie pointed out that the energies calculated for a wave and for a particle must be equal for anything that was behaving as both.
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λ = h/p Where: λ = wavelength of wave p = momentum of particle (i.e. mass x velocity) h = Planck's constant (6.63 x 10^-34 Js) The de Broglie Relationship links together wave (λ) and particle (p) properties. This explains the so called 'wave-particle duality'. |
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Early ideas treated the electrons in an atom like planets going round the sun. The path was a well-defined ORBIT. Now that we know that an electron has wave-like properties, with a wavelength (λ) the same order of magnitude as the size of an atom - such precision is impossible. All we can do is to determine the probability than an electron is in a certain place. Which principle is this referring to? |
THE UNCERTAINTY PRINCIPLE (established in 1927 by Heisenberg). |
