Wave Particle Duality Exam Questions Jan 2019 ANSWERS 1 2012 Rev H 2015 Rev H 2012 Rev H
Transcript
Wave Particle Duality Exam Questions Jan 2019 ANSWERS
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2012 Rev H
2015 Rev H
2012 Rev H
Wave Particle Duality Exam Questions Jan 2019 ANSWERS
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2012 Rev H
Wave Particle Duality Exam Questions Jan 2019 ANSWERS
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2016 CfE H
2016 CfE H
Wave Particle Duality Exam Questions Jan 2019 ANSWERS
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2013 Rev H
2012 Rev H
Kelly
Typewritten Text
Light is both a particle and a wave depending upon the situation. Light behaves as a classical wave when it diffracts and when this diffraction causes interference patterns which are evidence of a wave. Light also refracts as a wave where its speed and wavelength decrease when the wave enters a denser medium, The photoelectric effect demonstrates the particle nature of light where electrons are emitted from a negative metal plate ( photoemission ) when irradiated by electromagnetic radiation of high enough frequency. Photoemission demonstrates that an electron can only absorb one photon ("light particle") if the frequency is greater than a minimum (threshold) value. If the negative charged plate is irradiated with em radiation of a higher irradiance electrons will not be discharged. A greater "wave irradiance" should have a larger amplitude which should provide enough energy to free an electron, but it does not. So the light is not showing wave properties but particle behavior. Therefore because light can demonstrate both interference and photoemission it can be both a wave and a particle.
Wave Particle Duality Exam Questions Jan 2019 ANSWERS
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2014 Rev H
Wave Particle Duality Exam Questions Jan 2019 ANSWERS
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Wave Particle Duality Exam Questions Jan 2019 ANSWERS
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2015 Rev H
Kelly
Typewritten Text
In the photoelectric effect electrons are discharged when they absorb individual photons if the photons have enough energy ( hfo). This is called the work function of the metal. If the energy of the photon (E=hf) is less than the work function, it does not matter how many photons strike the metal plate, no electrons will have enough energy to be freed, as the individual photon can't give the electron enough energy. The coconut shy is a good analogy as the coconuts are like electrons and the balls are like photons. The coconut being knocked off the stand is like the electron being emitted by photoemission. If the ball is not thrown fast enough then it cannot knock the coconut off. It does not matter how many balls that are thrown, if they do not have enough (kinetic) energy they will not knock off the coconut. Where this is not such a good analogy is that an collision is used to knock down the coconut rather than absorb the ball as the electron absorbs the photon.
Wave Particle Duality Exam Questions Jan 2019 ANSWERS
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2017 CfE H
2017 CfE H
Wave Particle Duality Exam Questions Jan 2019 ANSWERS
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2018 CfE H
Wave Particle Duality Exam Questions Jan 2019 ANSWERS
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Wave Particle Duality Exam Questions Jan 2019 ANSWERS
