Light theory

He asserted that these rays were composed of particles of light. Beginning in and progressing over three decades, Isaac Newton developed and championed his corpuscular hypothesisarguing that the perfectly straight lines of reflection demonstrated light's particle nature; only particles could travel in such straight lines. He explained refraction by positing that particles of light accelerated laterally upon entering a denser medium.

Light theory

Quantum Theory of Light Wave-Particle Duality of Light Quantum theory tells us that both light and matter consists of tiny particles which have wavelike properties associated with them. Light is composed of particles called photons, and matter is composed of particles called electrons, protons, neutrons.

Ray theories in the ancient world

It's only when the mass of a particle gets small enough that its wavelike properties show up. To help understand all this let's look at how light behaves as a wave and as a particle.

Wave-like Behavior of Light In the s Christiaan Huygens, a Light theory physicist, showed that light behaves like a wave. One behavior of waves is Diffraction As the width of the slit becomes larger than the wavelength the wave is diffracted less. Another behavior of waves is Interference It was James Clerk Maxwell who showed in the s that light is an electromagnetic wave that travels through space at the speed of light.

The frequency of light is related to its wavelength according to Light theory look at an example calculation. What is its frequency? The unit s-1 is so common when talking about waves that it was given the name Hertz.

Thus, we would say that light with a wavelength of nm corresponds to a frequency of 6. As we saw in the example above, blue light is near the high frequency limit of our eyes. Red light, with wavelengths near nm are at the low frequency limit of our eyes.

Light that contains all frequencies in the visible region will appear as white light. More generally, the different regions of the electromagnetic spectrum are given different names.

Below are the names given to the different regions frequency ranges of light according to their frequency range. Particle-Like Behavior of Light At this point you may think that it's pretty obvious that light behaves like a wave.

So, why how do we know that light is really composed of particles called photons? Support for this idea comes from an experiment that is called the photoelectric effect. An important feature of this experiment is that the electron is emitted from the metal with a specific kinetic energy i.

Now anyone who is familiar with the behavior of waves knows that the energy associated with a wave is related to its amplitude or intensity. For example, at the ocean the bigger the wave, the higher the energy associated with the wave.

It's not the small waves that knock you over it's the big waves! So everyone who thought light is just a wave was really confused when the intensity of the light was increased brighter light and the kinetic energy of the emitted electron did not change.

What happens is that as you make the light brighter more electrons are emitted but all have the same kinetic energy.

Light theory

Well, they thought the kinetic energy of the emitted electron must depend on something. So they varied the frequency of the light and this changed the kinetic energy of the emitted electron.

This tells us that the kinetic energy is equal to the frequency of the light times a constant i. That constant is called Planck's Constant and is given the symbol h. This result is not consistent with the picture of light as a wave. An explanation that is consistent with this picture is that light comes in discrete packages, called photons, and each photon must have enough energy to eject a single electron.

Light theory

So, the energy of a single photon is: It was Albert Einstein who first explained thephotoelectric effect and he received the Nobel Prize in Physics for this work.

So, in summary-light is a particle with wave-like behavior.Quantum theory tells us that both light and matter consists of tiny particles which have wavelike properties associated with them. Light is composed of particles called photons, and matter is composed of particles called electrons, protons, neutrons.

Photography & Videography Company based in Bondi Beach Australia. Specialist Aerial and Underwater Artists. According to the classical theory of light and matter, the strength or amplitude of a light wave was in proportion to its brightness: a bright light should have been easily strong enough to create a large current.

Yet, oddly, this was not so. Photography & Videography Company based in Bondi Beach Australia. Specialist Aerial and Underwater Artists.

Theory of Light

Huygens theory was the successful theory of light wave motion in three dimensions. Huygen, suggested that light wave peaks form surfaces like the layers of an onion. In a vacuum, or other uniform mediums, the light waves are spherical, and these wave surfaces . Tired light is a class of hypothetical redshift mechanisms that was proposed as an alternative explanation for the redshift-distance relationship.

the Big Bang emerged as the cosmological theory most supported by the observational evidence.

Lighting theory essentials - Philips Lighting