Theory Of Light: The Wave Theory Of Light

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What is light?
It is an electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. (slideshare, 2014)
Light is part of the electromagnetic spectrum, which ranges from radio waves to gamma rays. (Andor, n.d.)
The wave theory of light
A Dutch astronomer, Christian Huygens, developed the wave theory of light in the late 1600s. In this theory, he thought of light as a longitudinal wave. This theory states that light is emitted in a series of waves that spread out from a light source is various directions. (Tanbeen, 2014)
James Maxwell added to the wave theory of light when he developed the theory of electromagnetism. It is said that light waves consist of both magnetic and electric fields and the fields
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In this experiment, Young allowed a ray of light to pass through a pinhole and strike a card. He hypothesised that if light contained particles or simple straight-line rays, the light not blocked by the card would pass through the slits and travel in a straight line and form two bright spots on the screen. But instead a pattern of light and dark strips formed. Young explained this pattern by comparing it to a water wave with crests and troughs. This then lead to the conclusion that light is a wave because as the light went through the slits and onto the screen, the light beams interfered with each other as there were dark and light beams on the page, meaning that where the crests met, the light was bright and where a crest and trough met the light was darker as crests and troughs cancel each other out. (William Harris and Craig Freudenrich, n.d.) It was the concluded that light must be a wave as it shows the properties of waves. The particle theory of light
It was first hypothesised by Isaac Newton that light consisted of a lot of small particles which were emitted in all directions from a source, such as metal.
Albert Einstein believed that light was composed of tiny particles called photons, and each photon has energy, after studying the photoelectric
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It is said that the energy of the light depends on the lights intensity according to the wave theory. This is not in agreement with the particle theory of light as a bright light with a low frequency, in other words below the threshold frequency, does not produce the photoelectric effect. The particle theory of light states that energy is directly proportional to energy, therefore intensity will not affect the energy of the particles.
The wave theory also cannot explain why increasing the intensity of the light will cause more electrons to be emitted. It is said that when the intensity is increased, electrons will be emitted with higher kinetic energy according to the wave theory. But it has been proved in the photoelectric effect that when the intensity of the light is increased, more electrons will be given off but with the same amount of energy as the lower intensity light. Only the frequency will affect the amount of energy of the particles.
It is therefore noted that the wave theory and the particle theory of light do have contradictions but both theories have been accepted by scientists due to the fact that both theories have been proven therefore coming to the conclusion that light displays properties of both waves and particles therefore having a dual

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