Wave Particle Duality of Light wave particle or

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Wave Particle Duality of Light wave, particle, or both?

Wave Particle Duality of Light wave, particle, or both?

The Behavior of Particles - Wave particle duality says that every elementary particle may

The Behavior of Particles - Wave particle duality says that every elementary particle may be partly described in terms not only of particles, but also as waves. - They are quantized as either a wave or particle. So everything’s a wave?

Wave Refresher

Wave Refresher

What is a wave? - A disturbance that propagates through a medium. We categorize

What is a wave? - A disturbance that propagates through a medium. We categorize them by their mediums, orientation, etc. . - There are different types of mediums: Mechanical, Gravitational, Electromagnetic. - Types of Orientation: Transverse, Longitudinal, Surface, Torsional. - Energy

Additional Wave - Wave Characteristics: amplitude, wavelength, frequency, period, etc. - Wave Speed: The

Additional Wave - Wave Characteristics: amplitude, wavelength, frequency, period, etc. - Wave Speed: The properties and travelled medium that determine a wave’s speed. - Diffraction: The bending or spreading of a wave around an obstacle or through an opening. - Interference: The combination of separate waves in the same region of space to produce a resultant wave. - Doppler Effect: The shift in frequency of a wave when the wave source and/or the Sound vs Light - Sound waves are millions of times longer than light waves - Diffraction is more easily observed for sound than light in everyday experience - You can hear around corners but you cannot see around them - Light sources cast noticeable shadows

But what about particles? ?

But what about particles? ?

What are particles? - A particle is a general meaning. - Physically, a particle

What are particles? - A particle is a general meaning. - Physically, a particle is a small localized object that can ascribe characteristics such as mass or volume. - They vary in size and/or quantity from subatomic particles (electrons) to microscopic particles (atoms, molecules) - Particles model the composition of nature and make up all matter in our universe. - We refer to the standard model when doing so.

So what is Light?

So what is Light?

The Nature of Light can be described as a composition of electromagnetic waves that

The Nature of Light can be described as a composition of electromagnetic waves that does not need a medium to propagate through. - With this model we have electromagnetic waves at a particular frequency and wavelength. These waves make up the our visual spectrum. Light can also be described as a series of particles (Photons). - Depending on the situation, light behaves like a particle.

Well how did we get here?

Well how did we get here?

Huygens-Fresnel Principle -1678, Christiaan Huygens modeled that every point of a wave front may

Huygens-Fresnel Principle -1678, Christiaan Huygens modeled that every point of a wave front may be considered the source of secondary wavelets that spread out in all directions with a spread equal to the speed of the waves propagation. -He was not able to demonstrate these models to prove his theory.

Corpuscular Theory of Light -17 th century, Isaac Newton largely developed the Corpuscular Theory

Corpuscular Theory of Light -17 th century, Isaac Newton largely developed the Corpuscular Theory of Light to disprove Huygen’s wave principle. Simply, his theory of light was consisted of a shower of projectiles that traveled in a straight line. -Couldn’t explain diffraction, interference, or the polarization of light.

Young’s Double-Slit Experiment - Early 19 th century, Thomas Young - Provided evidence that

Young’s Double-Slit Experiment - Early 19 th century, Thomas Young - Provided evidence that light acts as a wave - Displayed interference pattern

Young’s Experiment conclusions - Light displayed characteristics of both our classically defined waves and

Young’s Experiment conclusions - Light displayed characteristics of both our classically defined waves and particles - Created an interference pattern, was the first to correctly interpret this behavior - Displayed the probabilistic nature of quantum phenomena

Photoelectric Effect -The photoelectric effect was first discovered in 1887 by Heinrich Rudolf Hertz.

Photoelectric Effect -The photoelectric effect was first discovered in 1887 by Heinrich Rudolf Hertz. While working on radio waves, Hertz observed that when ultraviolet light shines on two metal electrodes with a voltage applied across them, the light changes the voltage at which sparking takes place. - These unexpected behaviours led Albert Einstein in 1905 to formulate a new corpuscular theory of light in which each particle of light or photon contains a fixed amount of energy that depends on the light’s frequency.

De Broglie Hypothesis - 1924, Louis-Victor De Broglie’s Ph. D thesis proposed that light

De Broglie Hypothesis - 1924, Louis-Victor De Broglie’s Ph. D thesis proposed that light has both wavelike and particle like properties, electrons also have wave-like properties. - The wavelength associated with an electron is related to its momentum, p, through the Planck constant. (6. 62607004 × 10 -34 m 2 kg /s) - This relationship is now known to hold for all types of matter.

Nowadays

Nowadays

Thanks to our historical achievements. . - Physicists now accept that all entities in

Thanks to our historical achievements. . - Physicists now accept that all entities in nature behave as both a wave and particle depending on the situation. - The act of measurement causes a set of probabilities, which is governed by a probability distribution function that comes from a “wave”. This will lead to particle like results.

References 1) Ruechardt, Edward. Light Visible And Invisible. 1 st ed. Michigan University Of

References 1) Ruechardt, Edward. Light Visible And Invisible. 1 st ed. Michigan University Of Michigan Press, 1958. Print. 2) "The Nature Of Light – The Physics Hypertextbook". Physics. info. N. p. , 2017. Web. 28 May 2017. 3) Serway, R. A. and Jewett, J. W. (2007) Physics for scientists and engineers, chapters 1 -39. 7 th edn. United States: Wadsworth Publishing Co. 4) "Electromagnetic Waves And Interference | Physics | Science |Khan Academy". Khan Academy. N. p. , 2017. Web. 31 May 2017. 5) Weiss, Richard J. A Brief History Of Light And Those That Lit The Way. 1 st ed. Singapore: World Scientific Pub. , 1996. Print.

Questions 1. What medium is required for light to travel? 2. Does light display

Questions 1. What medium is required for light to travel? 2. Does light display interference patterns? 3. Who tried to disprove Huygen’s wave principle? 4. Since light can be described in terms of waves and particles, could light and/or electromagnetic waves be considered magic?