Quantum physics: The photoelectric effect What is the photoelectric effect? The photoelectric effect is when a clean metal surface emits electrons after light‚ especially ultraviolet‚ has been shone on at it. This happens because of a process called photoelectric emission whereby a single photon package of electromagnetic energy‚ called a quantum‚ is absorbed by metal surfaces. This energy is then transferred to one single electron which can then be released by the metal and that released electron
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various effects on people’s health. To begin with‚ cell phones are emitting radiation‚ electromagnetic wave‚ which is threatening people’s health. Firstly‚ radiation causes to die of brain cells which are not renewable. The die of brain cells may cause amnesia and because of not being renewable it cause early aging. Moreover‚ if cell phones are used longer than ten years‚ then their radiation forms brain tumors. Secondly‚ radiation affects heart rhythm. Disorder of rhythm leads to send blood to cells irregularly
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matter cannot be explained on the assumption that the particles obey the laws of classical mechanics. At the end of 19th century and in the beginning of 20th century‚ many new phenomena such as photoelectric effect‚ x-rays‚ line spectra‚ nuclear radiation were discovered which wanted explanation on the basis of classical physics. Laws of classical mechanics failed to explain the above said newly observed properties of matter. Therefore the need of new concepts was felt in many areas of physical
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The current flows through the circuit since the temperature of the two junctions are different. IR Sensor -This device emits and/or detects infrared radiation to sense a particular phase in the environment. Generally‚ thermal radiation is emitted by all the objects in the infrared spectrum. The infrared sensordetects this type of radiation which is not visible to human eye. Touch
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Test# 2 Name: Group: | |Question text |Criteria | |Q1 |[pic] | | | |Where I0 is the initial intensity of photons and [pic] is the linear……………..which describes the fraction of beam of ………rays or |
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Ms. Wilson Chem‚ Blk 10 31 October 2012 Atomic Emission Spectra Lab Atomic spectroscopy is the determination of elemental composition by its electromagnetic or mass spectrum. An arrangement of all wavelengths of electromagnetic radiation is called the spectrum; the plural being spectra. As light passes through a prism‚ the frequencies of light emitted by an element separate into separate lines to give the atomic emission spectrum of the element. There are two spectrums in the lab: the incandescent
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in space—instead of bullets. This explains how rainbows work. In fact‚ light is both. This "wave-particle duality" is one of the most confusing—and wonderful—principles of physics. Light is radiant energy‚ usually referring to electromagnetic radiation that is visible to the human eye‚ and is responsible for the sense of sight.[1] Visible light is usually defined as having a wavelength in the range of 400 nanometres (nm)‚ or 400×10−9 m‚ to 700 nanometres – between the infrared‚ with longer wavelengths
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NATIONAL SENIOR CERTIFICATE EXAMINATION NOVEMBER 2008 PHYSICAL SCIENCES: PAPER I Time: 3 hours PLEASE READ THE FOLLOWING INSTRUCTIONS CAREFULLY 1. This paper consists of: • a question paper of 17 pages • a data and formula booklet of 3 pages (i – iii) Please make sure that your question paper is complete. 2. 3. 4. 5. 6. Remove the pages of data and formulae from the middle of this question paper. Use the data and formulae whenever necessary. Read the questions carefully. In Question 1 answer 1
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in radar help to decide the range‚ angle‚ or speed of objects. Radio waves have the longest wavelength‚ smallest frequency‚ and the least energy of all electromagnetic waves. These waves are a type of electromagnetic radiation‚ which additionally include microwaves‚ infrared radiation‚ x-rays‚ and gamma rays. Other important uses of radio waves are for television‚ cellphones‚ and
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gas held together by its own gravity in which the energy generated by nuclear reactions in the interior is balanced by the outflow of energy to the surface‚ and the inward-directed gravitational forces are balanced by the outward-directed gas and radiation pressures. Nova: A star that suddenly becomes much brighter and then gradually returns to its original brightness over a period of weeks to years. Supernova: A rare celestial phenomenon involving the explosion of most of the material in a star
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