...NUMBER: 00037471 NAME OF ACTIVITY: BLACKBODY AND THE RADIATION LAWS BLACKBODY RADIATION The term black body was introduced by Gustav Kirchhoff in 1860. When used as a compound adjective, the term is typically written as hyphenated, for example, black-body radiation, but sometimes also as one word, as in blackbody radiation. Black-body radiation is also called complete radiation or temperature radiation or thermal radiation. "Blackbody" A black body is a theoretical object that absorbs 100% of the radiation that hits it. Therefore it reflects no radiation and appears perfectly black. The stove is a perfect example of blackbody radiation. In practice no material has been found to absorb all incoming radiation, but carbon in its graphite form absorbs all but about 3%. It is also a perfect emitter of radiation. At a particular temperature the black body would emit the maximum amount of energy possible for that temperature. This value is known as the black body radiation. It would emit at every wavelength of light as it must be able to absorb every wavelength to be sure of absorbing all incoming radiation. The maximum wavelength emitted by a black body radiator is infinite. All objects absorb electromagnetic radiation at different temperature, these objects in turn send back out this heat absorbed which is called thermal radiation. The hotter the object the more thermal radiation it gives off some surfaces are better than others...
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...Blackbody Lab Website for virtual lab http://phet.colorado.edu/sims/blackbody-spectrum/blackbody-spectrum_en.html t? How can you tell? 2. Does the light bulb produce X-rays? How can you tell? 3. In the spectrum made by the light bulb, which wavelength is most intense and what part of the electromagnetic spectrum is this? Wavelength _______________________ Type:_____________________ 4. Given your answer to #3 is an incandescent light bulb very good for its intended use? Explain. Click Save. (The curve will turn yellow) Part II Comparing spectra of different objects. Set the temperature to 615 K, this is comparable to the temperature in a very hot oven. Notice that the RED line is the radiation emitted by the oven. The line should appear flat, but it isn’t. Zoom the y axis in to read .001 and zoom the x-axis out to 12. 1. How is the curve produced by the oven similar to the line produced by the light bulb? 2. How is the curve produced by the oven different from the curve produced by the light bulb? 3. If the power goes out in your kitchen, could you see in the dark using light from the hot oven? Explain. Click Clear to clear the graphs. Set the temperature to 5800K. This is approximately the surface temperature of the sun. You’ll need to zoom in on the horizontal axis and zoom out on the vertical axis. 4. What is the most...
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...Introduction For the purpose of studying combined radiation and free convection heat transfer, this experiment measured the surface temperature of two aluminum flat plates during heat-up. Both plates' lower surfaces were well insulated. For comparison, one plate was considered to be ideal blackbody, which is a perfect absorber and emits; the other one was polished, yielding different radiant properties. According to the procedure, both plates were heated under the lamp from room temperature; plates' temperature was measured with a thermocouple and recorded with LabView Program. To analyze the results, appropriate assumptions were made and correct conservations of energy were chosen. Results and Discussion Based on the data collected in the experiment, Temperature vs Time were plotted for both plates, as shown in figure 1 and figure 3. Our plates were exposed under the lamp for a longer time than claimed in the procedure to reach a relatively steady state, because the lamp we were using was weaker than normal ones. Figure 1, Temperature vs Time for Blackbody Plate Energy terms in the energy balance equation were also calculated and plotted as shown in figure 3 and figure 4. Equations that used to do all the calculations can be found in Appendix A and Appendix B. All the calculations were done using Microsoft Excel. Figure 2, Energy terms vs Time for Blackbody Plate Irradiation, Gtot was calculated to be 1456.95 W/m2. Since the initial temperature of plate surface...
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...turn into a special form of energy. This is, however, only triggered by certain radiation. This radiation is that of Apricorns, those nut-like fruits people made Pokéballs out of in ancient times. The inside of an Apricorn's shell contains energy drainers, a sort of biological energy black holes - they let out that certain radiation and they can suck energy in to their centers. Those are there to protect the Apricorns from Pokémon that might want to eat them in a very effective way - a Pokémon that cracks the shell of an Apricorn will be hit by the radiation, turn into energy, and be sucked towards the Apricorn. This can imprison smaller Pokémon inside forever - which additionally provides the Apricorn with more power to suck in more Pokémon - or if it is a powerful Pokémon, it would feel dizzy and perhaps decide the Apricorn is not good to eat. If a Pokémon actually eats the Apricorn, however, it dies and the energy drainers release the energy they contained. Different types of Apricorns, targeted as food for different kinds of Pokémon, contain different kinds of energy drainers which suck in different types of energy - usually some form which is dominant in some Pokémon and not others (such as Water Pokémon, fast Pokémon, heavy Pokémon, etc.). All Apricorns contain some drainers for all variations, though, so they can all catch anything that is weak enough. Humans also react to the radiation from the Apricorns, but are nowhere near as unstable as Pokémon and only long-term...
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...into physics by Max Planck in 1900.[3] Planck derived the thermal equilibrium energy distribution for electromagnetic radiation (also called the “blackbody problem” because of the experimental apparatus). The quantity of interest was dr/df where r denotes the energy density and f the frequency (Fig. 1). No one had been able to derive dr/df from the first principles of statistical mechanics. One serious problem was in the high frequencies, which contributed infinite energy when one integrated over all frequencies to obtain the total energy! Planck thought about the charged particles whose simple harmonic motion generated harmonic electromagnetic waves of the same frequency. He discovered that if he assumed a particle oscillating with frequency f could carry only the discrete energies 0, hf, 2hf, 3hf..., where h was a constant, he could derive the distribution function: dr/df = (8ph/c3) f 3 (e hf/kT − 1)−1 , where c denotes the speed of light in vacuum, k Boltzmann’s constant, and T the absolute temperature. This function fit the data provided h was assigned the value 6.6×19−34 J · s, now called Planck’s constant.[4] The smallness of h accounted for the lack of energy graininess in macroscopic oscillators such as pendulums. To Planck in 1900, the quantum was a property of the mechanical oscillators that happen to generate light. Radiation itself, in principle, would still...
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...and relationship between incoming and outgoing rays produces a virtual image which is identical to the real object. Refraction - light rays moving from one transparent medium to another may be bent, or refracted. The amount of refraction of light rays depends upon their angle of incidence in the same way reflection does, and also on specific properties of the different media and how fast light travels in each. 3) Know the evidence for the wave nature of light. Pages 166-170 The wave theory explains how light travels through space, and how it interacts with matter to be reflected, absorbed, or refracted 4) Know the evidence for the particle nature of light. Page 170-171 The particle theory can explain the photoelectric effect and blackbody radiation. 5) No the 5 basic ideas of classic atomic theory Bottom page 180-top of page 181 1. All elements consist of particles called atoms. 2. All atoms of an element are identical and have the same mass. 3. Atoms of each element are different from those of other elements and have different mass. 4. Atoms chemically combine in definite whole-number ratios to form chemical compounds 5. Atoms are...
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...Telescopes in Astronomy Jennifer Boyer SCI/151 June 12, 2015 Robert Austin Telescopes in Astronomy What people currently know about the universe, along with all of its contents, is due in large part to the invention of telescopes. This paper discusses the science of sunlight and stars by explaining how the telescope has changed people’s view of the universe, as well as their place in it. This essay also discusses the major designs of telescopes, provides a list of each design’s strengths and weaknesses, describes the best places to build ground-based telescopes and why astronomers choose those places, and contrasts the strengths and weaknesses between building telescopes on Earth, in orbit, or even on the moon. Additionally, this paper explains how different frequencies of light tell more about the birth, life, and death in the nature and properties of the Sun, stars, and the universe. Lastly, this essay explains how telescopes operate in wavelengths of light that range from radio waves to gamma rays. How Telescopes Changed People’s View The invention of the telescope significantly impacts the way people in the past and present view the Earth, other planets and solar systems, as well as the universe as a whole (Bennett, J., Donahue, M., & Schneider, N., & Voit, M., 2015). Until the invention of Galileo Galilei's (1564-1642) simple telescope, many people thought that the earth was the center of our solar system (Bennett, J., Donahue, M., & Schneider...
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...electromagnetic radiation, types of spectra-(absorbance, emission and fluorescene) types of spectroscopy – (principle, instrumentation and applications of atomic absortion spectroscopy, UV Visible Spectroscopy, Nuclear Magnetic Resonance Spectroscopy and Electron Spin Resonance Spectroscopy) Spectroscopy is the study of the absorption and emission of light and other radiation by matter, as related to the dependence of these processes on the wavelength of the radiation. More recently, the definition has been expanded to include the study of the interactions between particles such as electrons, protons, and ions, as well as their interaction with other particles as a function of their collision energy. Spectroscopic analysis has been crucial in the development of the most fundamental theories in physics, including quantum mechanics, the special and general theories of relativity, and quantum electrodynamics. Spectroscopy, as applied to high-energy collisions, has been a key tool in developing scientific understanding not only of the electromagnetic force but also of the strong and weak nuclear forces. The basic principle shared by all spectroscopic techniques is to shine a beam of electromagnetic radiation onto a sample, and observe how it responds to such a stimulus. The response is usually recorded as a function of radiation wavelength. A plot of the response as a function of wavelength is referred to as a spectrum. Electromagnetic radiation consists of...
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...PHYSICS HISTORY OF PHYSICS Physics (from the Ancient Greek φύσις physis meaning "nature") is the fundamental branch of science that developed out of the study of nature and philosophy known, until around the end of the 19th century, as "natural philosophy". Today, physics is ultimately defined as the study of matter, energy and the relationships between them. Physics is, in some senses, the oldest and most basic pure science; its discoveries find applications throughout the natural sciences, since matter and energy are the basic constituents of the natural world. The other sciences are generally more limited in their scope and may be considered branches that have split off from physics to become sciences in their own right. Physics today may be divided loosely into classical physics and modern physics. Ancient history Elements of what became physics were drawn primarily from the fields of astronomy, optics, and mechanics, which were methodologically united through the study of geometry. These mathematical disciplines began in antiquity with the Babylonians and with Hellenistic writers such as Archimedes and Ptolemy. Ancient philosophy, meanwhile – including what was called "physics" – focused on explaining nature through ideas such as Aristotle's four types of "cause". MAJOR FIELDS Branches of physics Physics deals with the combination of matter and energy. It also deals with a wide variety of systems, about which theories have been developed that are used by physicists...
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...reactors, causing a nuclear accident on 11 March 2011. (http://www.world-nuclear.org/info/fukushima_accident_inf129.html) What is radiation and how it damage people. Radiation may be defined as energy traveling through space. Non-ionizing radiation is essential to life, but excessive exposures will cause tissue damage. All forms of ionizing radiation have sufficient energy to ionize atoms that may destabilize molecules within cells and lead to tissue damage. (http://www.foodandwaterwatch.org/food/foodsafety/the-nuclear-accident-in-japan/) History of radiation Japanese radiation generation How radiation influence the agricultural When a nuclear power plant releases radiation, many foods and edible plants can absorb radioactive particles, which can be toxic to humans. Fuel rods that are exposed to the atmosphere may release iodine, which can be carried by the wind and end up on grass and plants. Read more: Nuclear Radiation Effects on Plants | eHow.com http://www.ehow.com/info_8195801_nuclear-radiation-effects-plants.html#ixzz2KdNfqMPO Influence area Radiation can transport by cloud and water. ( http://www.socialintensity.org/) Japan radiation map. (Base on the wind and water, then compare with the map which published by japan media) How radiation food harm people Radioactive particles accumulate in the body and continue to release radiation. This may lead to changes in the molecular structure of the cells and has been linked to cancer....
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... | |ionizing potential. | | | | | |For example, "they | | | | | |throw bowling balls" | | | | | |at the body’s | | | | | |molecules, DNA, | | | | | |tissue, etc. which can| | | | | |cause radiation | | | | | |poisoning and | | |...
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...three Fukushima Daiichi nuclear reactors by stopping the cooling as a result of interruption in the power supply. With no cooling in the reactors, the energy released from radioactive decay rose threatening not to be handled by the containment structures at the plant (Eisler 17). Water exposed to high levels of radiation threatened to damage the containment structure due to hydrogen build up. With damage to the containment structure, the environment was at high risk of full blown radiation contamination. The danger posed by the accident was the accident was the spread of radioactive contamination to water or the environment that the nearby residents came into contact with. This is why the Japanese government budgeted close to $14 billion for the radiation clean up and immediate relocation of residents (Eisler 29). One of the isotopes still found in the accident site is Cesium-137 that decays according to the following equation 55Cs^137 --> 56Ba^137 + -1e^0. The isotope could lead to development of acute radiation syndrome in humans that affects the skin, digestive system and hair (Loveland et.all 45). Cancer can develop as a result of not receiving appropriate radiation treatment. Nuclear energy is a safe way of producing energy if the right protective measures are taken. In fact, history implies that it rarely causes deaths or illness compared to other methods of producing energy such as using...
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...concern the impact of releasing radioactive radon gas on your health but I’m here to assure you that you are not in too much danger and do not have to over worry. First, let’s consider the short-term effects of radiation damage to cells. If a whole body exposes to less than 100 rem (1 Sievert) dose of radiation, people will experience no short-term radiation illness. You will expose to approximately an extra 1 milli-Sievert whole-body dose per year due to the leak. The dose is far below 1 Sievert. So you will not be sick because the cells in your body can repair the tiny damage naturally. Then, I’ll talk about extra risks of getting cancers. According to the Linear Hypothesis which predicts cancer effects at very low levels, each of you will get 4*10^-5 extra risk of getting cancers each day, which is only 0.04 extra cancers. When we expand the time range into a year, extra 14 to 15 people in 1000 of you will get cancers due to radiation. Much fewer people than 14 will actually die from cancer. Even without radiation, about 40% people will get cancer and about 20% of them will die of it. So even if there is no releasing radiation, about 400 people among you will get cancer sometime in your lives and 200 people will die for it. So the danger of getting cancer from radiation is very minimal compared to the natural rate. Besides, the linear hypothesis is not approved even though it is widely used. There are possibilities that 1mSv will not produce any extra cancer risk at all. Therefore...
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...Not knowing her destiny the only thing she could do was pray because she still had two children to raise. Before she started her radiation treatments her doctor explained she would no longer be able to bare children, she would be weak from the treatments, she would have treatments five days a week, twice a day lasting for 12-13 weeks, and the dosage of radiation her body would be enduring would be a total of 240 degrees. Melody agreed and started her treatments March of 1996. The radiation placed wear and tear on her body which caused her to drop to a size zero and was weighing in at 97 pounds. Her body was taking in so much of radiation causing her to become so weak that carrying or picking up a gallon of milk was a hard task. Throughout her treatment process she carried a foul rotten odor (similar something that smelled like metallic) from her body due to the excessive amounts of radiation she was receiving. Lastly, she was unable to sleep or eat. Going to bed and waking up hungry was a bad feeling and was causing her body to deteriorate. Melody did this for weeks until one day while taking a nap GOD came to her in a dream and fed her orange juice. While feeding her the orange juice he said to her, “Always drink orange juice.” Waking from that nap she felt replenished and full. By the time 1997 had rolled around, Melody had completed her radiation treatments. Her cancer had shrunk from the size of a lemon to the size of a sesame seed and has...
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...Importance of Radiation Safety in Computed Tomography Advances in computed tomography (CT) technology have continued to open new clinical applications, including several procedures for evaluating heart disease. The speed with which CT technology is changing is somewhat unparalleled in medical imaging. The equipment is becoming faster and faster. In the 1990s, a patient had to remain in a CT gantry for a period of approximately 10 minutes for a chest CT, whereas now it takes a few seconds to scan the entire chest. This may give the impression that radiation dose in CT is small, which is not the case. To give an example, a typical chest CT can impart a radiation dose equivalent to hundreds of chest radiographs. The offshoot of higher speed is that shoulder to pelvic scans or even head to pelvic scans are becoming more common, and this is raising questions of justification. Repeat scans on the same patients are also not uncommon. It is becoming clear that many CT examinations (typically one third) are unjustified and can be avoided through appropriate clinical judgment. There is no doubt that newer technology has increased the usefulness of CT examinations in areas where earlier there was little justification of CT. It has been documented that radiation dose to the patient can be reduced significantly through optimization actions. However, repeated examination on the same patient, or examination on a child or pregnant woman, requires a higher level of attention to radiation doses...
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