Photoelectric effect

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  • Photodetectors Essay

    incoming photon, which is detected by an electronic circuit, while thermal detectors convert optical energy to heat, which then generates an electrical signal.3 Herein, two types of photodetectors are examined: a PD and a PMT. Although both detectors detect light by converting incident photons to electrical signals, they differ in the way they achieve this. The PD is a p-n junction semiconductor device that generates current when the photodiode absorbs a photon of sufficient energy. This process creates an electron-hole pair through a photoelectric effect. The holes move to the anode while electrons move to the cathode creating a photocurrent. PDs have fair sensitivity and relatively fast response times, but have some limitations due to noise.4 A PMT is a single tube that consists of a photocathode, a series of dynodes, and an anode. Arriving photons strike the photocathode, from which an electron is ejected as a consequence of the photoelectric effect. This electron is directed to an electron multiplier though a secondary emission process.4 Thus, the large number of electrons arriving at the anode creates a sharp current response that is detectable. Like PDs, PMTs also have relatively fast response times, but they are exceptionally sensitive, allowing them to be used in single photon studies.4 In order to study these two photodetectors, we analyzed three properties: sensitivity, shot noise, and gain. The sensitivity, S, is defined as the measure of the average current, I,…

    Words: 918 - Pages: 4
  • Isaac Newton's Theory

    to accurately predict its behaviour. His ‘imaginary’ discrete energy packets had no place in this structure. Planck’s equation was not, at first, very popular. The rest of the physics community had the same problems with it as he did, the fact that he had to use a mathemagical trick to get the right curves for blackbody radiation. Light did not come in quanta, so there had to be a better equation waiting to be found. Albert Einstein had other ideas. …That Changed Reality The Photoelectric Effect…

    Words: 1743 - Pages: 7
  • Wave Interference In Alice In Quantumland

    This is what is called constructive interference. The Classical Mechanic then directed Alice’s attention to the area of the water where the water was practically undisturbed. In this case, the water from one gap created a rise in the water as Alice had previously observed. This time, however, the water from the second gap created a trough in the water’s surface. The Classical Mechanical explained to Alice that, in the case that one wave goes up above the surface of the water and one goes below…

    Words: 635 - Pages: 3
  • Albert Einstein's Photoelectric Effect

    Einstein developed the theory that light travels at the same speed no matter the “frame of reference” which contradicted Galileo’s previously believed theory of relativity, giving the scientific community a different idea to ponder (Hayden 12). Albert discovered that the universe was constantly expanding, later proven by Edwin Hubble, which discredited the previous view that the universe was static or never changing, altering the scientific world’s past beliefs (Biography.com 14). One of…

    Words: 1020 - Pages: 5
  • Albert Einstein Photoelectric Effect

    “labels” and became very famous for his scientific knowledge. When Einstein was 16 years old, he always wondered what it would be like to ride his bike on a beam of light, 10 years later he came up with a special theory of relativity, which lead him to find out that light always travels at the same speed (which is 186,000 miles/second). Albert Einstein’s career, beginning with an extensive education through physical science, had a lasting influence on the photoelectric effect, Special/General…

    Words: 1124 - Pages: 5
  • Environmental Effects Of Forest Fragmentation

    impact the surrounding ecosystems in a negative way. This can be referred to as forest fragmentation. Forest fragmentation negatively affects the forests connectivity and function. Fragmentation caused by mine reclamation is said to be “two-sided because both the effect that natural habitat has on the restored area, and the effect the restored area has on natural habitat.” (Craig et al. 2015) It is known “edge effects increase with increasing contrast between habitats forming the edge with…

    Words: 767 - Pages: 4
  • How Children Succeed By Paul Tough: Article Analysis

    behavior and way of thinking. He bases this premiere on an experiment done by psychologists about humans, but done in rats. This experiment was about how rats being groomed and licked by their mother will affect their future. Psychologists believe it’s the most parallel to grooming and licking; the experiment done in rats. The effects of the experiment were the opposite of what they thought they would find. They found that parents who respond to their children immediately and whom are very…

    Words: 818 - Pages: 4
  • Photo Editing Essay

    Media has control over our minds. Advertisers, movies, television shows, and magazines feed people’s minds with a false and perverted (“to change [something good] so that it is no longer what it was or should be” (Webster) view on body image for both men and women. Media uses tools such as Photoshop to change the model into a so-called perfect human form, which is usually unnatural and unachievable by the average person. Eating disorders, and low self-esteem seem to be a side effect of this.…

    Words: 784 - Pages: 4
  • The Gulf Oil Spill

    The Gulf oil spill has been recognized as the worst oil spill in U.S. history. The initial environmental impact was obvious, as the water was flooded with oil for 87 days. The surrounding wildlife and marine life coated in oil, and the waters thick with sludge as an estimated 4.9 million barrels of oil leaked into the Gulf. Years later, is the Gulf free of oil? We no longer see the discolored waters, and the animals covered in blackness, but the Gulf is still facing lasting challenges with long…

    Words: 1118 - Pages: 4
  • Skinner's Theory Of Punishment

    This theory was supported by Thorndike and Skinner who believed that punishment was not effective at reducing the rate of responding and that in the absence of punishment responding rates would increase (Holth, 2005). This effect was noted by Skinner in an experiment he conducted with rats in 1938 (Holth, 2005). Skinner found that when rats were punished for pressing a lever, for a particular period of time, their rate of responding decreased. However, when the punishment procedure was…

    Words: 1232 - Pages: 5
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