The Photoelectric Effect Essay - 1436 Words

Introduction The Quantum Theory was the second of two theories which drastically changed the way we look at our physical world today, the first being Einstein’s Theory of Relativity. Although both theories revolutionized the world of physics, the Quantum Theory required a period of over three decades to develop, while the Special Theory of Relativity was created in a single year. The development of the Quantum Theory began in 1887 when a German physicist, Heinrich Hertz, was testing Maxwell’s Theory of Electromagnetic Waves. Hertz discovered that ultraviolet light discharged certain electrically charged metallic plates, a phenomenon that could not be explained by Maxwell’s Wave Theory. In order to explain this phenomenon termed the†¦show more content†¦The threshold frequency varies with each metal. When the sodium plate was exposed to high frequency light, electrons were emitted and were attracted to the positive terminal, causing a flow of current. However, when a low frequency light was used no electrons were emitted and therefore there was no current. Observations of the Photoelectric Effect 1. Current flows as soon as the negative terminal is illuminated. 2. High frequency light causes electrons to be emitted from the sodium, however, a lower frequency light does not. 3. The energy of the emitted electrons does not depend upon the intensity (brightness) of the light, it is dependent on the frequency of the light. A higher frequency of light causes higher energy electrons. 4. The amount of current that flows is dependent upon the intensity (brightness) of the light. Prior to the 1900’s light was considered to be wave-like in nature. This was due to the success of Maxwell’s Electromagnetic Theory. However, much of the phenomenon observed during the photoelectric effect was in contradiction to the Wave Theory of Light. For instance, the energy contained in electromagnetic waves, and the amount of energy that would strike a sodium electron can be calculated. Such a calculation shows that an electron could indeed gain enough energy to be liberated from the sodium, but only after the sodium had beenShow MoreRelatedContents Introduction: 2 What is the photoelectric effect? 2 Origin of the photoelectric1000 Words   |  4 PagesIntroduction: 2 What is the photoelectric effect? 2 Origin of the photoelectric effect: 3 5 Modern day applications of the photoelectric effect: 5 Bibliography: 6 Contributors: 6 â€Æ' On how the photoelectric effect affects our daily lives Christiaan Myburgh Elmar Roux Tijmen van der Steenhoven Introduction: The photoelectric effect has a big effect on our daily lives. It is used in several important technological devices, like solar panels and anti-burglary sensors. The effect was discovered over a longRead MoreThe Physics Of X Ray Tube2196 Words   |  9 Pageswhen it interacts with nuclei creating a nucleon fragment. There are five specific mechanism interactions between x-ray photons and matter. The coherent scattering, compton effect, photoelectric effect, pair production and phtoto distegration. Most commonly used in radiology are compton effect and photoelectric effect. Coherent Scattering the x-ray photon interacts with a whole atom and causes it to become excited. This excitation causes the atom to released an x-ray photon on equal wavelengthRead MoreSolar Energy Paper : The Sun987 Words   |  4 Pagesspread out through a large field. No matter where they are located, they all face directly straight up towards the sun to harvest the light directed onto them. Using what are called solar cells, or photovoltaic cells, they are able to use the photoelectric effect which is the ability of matter to emit electrons whenever a light is shined upon it. 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The electrons enter the space charge surrounding the filament and the space charge effect prevents more electrons from being boiled off determined by the mill iamperage. Once the radiographer presses the rotor button the tube current electrons to travel to the anode side. The tungsten target rotates and attracts the electrons to hit theRead MoreAdvantages And Disadvantages Of Traditional Infrared Touch Laptops1827 Words   |  8 PagesAlbert Einstein in his Nobel prize winning 1905 paper (Handbook of Photoelectric Sensing, 1993). Einstein made the bold proposal that light traveled through space in concentrated bundles (Known today as protons) (Handbook of Photoelectric Sensing, 1993). Einstein also outlined how protons when striking materials liberate photoelectrons, and the energy from the photoelectrons can be used to create a small current (Handbook of Photoelectric Sensing, 1993). 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Factors: Some of the possible factors that could affect my experiment are * ------------------------------------------------- The angle of the solar cell. * ------------------------------------------------- The distance of the solarRead MoreTwo Features of the Photo-Electric Effect Essay2277 Words   |  10 PagesThe photo electric effect, which was first documented by Einstein in 1905, and posited that the energy of liberated electrons is linearly dependent on the frequency of incident photons. This paper investigates this relationship and measures Plancks constant ($4.36\pm 0.04\e{-21}$MeVs), and the work function of the photo diode ($-1.52\pm0.02$V). Another phenomena which is checked is the charging time of the stopping potential voltage. While there was some dependence between stopping voltageRead MoreA Basic Understanding Of How Solar Energy And Solar Panels Work1882 Words   |  8 Pagesthem at a quicker rate than we can produce them. Eventually, we will run out. Therefore, a contingency plan must be made, beginning with tasks such as using alternative energy sources to power our machines. This project is a means to combat the effects of pollution and consummation of fossil fuels. Task 2. Form a basic understanding of how solar panels work In order to initialize this project, it is crucial to understand how the technology we are using works. The concept of using solar energy and

Analyzing the Iconic Image of Che Guevara - 1913 Words

It is hard to travel anywhere in the world without seeing somewhere the iconic image of Che Guevara on a T-Shirt, souvenir, or poster. The original photographer, and the Irish artist who turned that photograph into a print, are virtually unknown. However, their image has been redistributed to the point where it can effectively be called an icon or a meme. There is no small amount of irony in the fact that an icon of communism has become an emblem of capitalism: as the image has been bought and sold countless times in countless countries around the world. The iconic image of Che Guevara has a hipster chic to it, but also political panache. To don the Che Guevara image means one does not agree with the establishment and is part of the 99%. However, Che Guevara is a controversial figure too. The image has been banned in some parts of the world, because Che was a radical revolutionary who was not against the use of armed uprisings in communist revolts. Therefore, the iconic Che Guevara i mage created first in Cuba and turned into pop art by an Irishman is a paradoxical and typically postmodern cultural meme. The Che Guevara iconic image represents an exact moment in history that is distinct and important. The most specific moment in time the iconic image represents was the second Alberto Kordas shutter snapped and he took the photograph for a local Havana newspaper in 1960; he was covering a mass funeral ¦held by Fidel Castro for a group of Cubans killed in the explosion of

Challenges of the 21st Century and Pakistan Free Essays

CHALLENGES OF THE 21ST CENTURY AND PAKISTAN Dancing around the fire is not the solution to any problem. One should try to see beneath the surface in order to grasp an idea about the basic issue. Despite a stream of stung words and announcements made by the previous governments of Pakistan, there is a woeful neglect in accepting the challenges of the present millennium rather the situation has taken a quantum leap for the worse. We will write a custom essay sample on Challenges of the 21st Century and Pakistan or any similar topic only for you Order Now On the other hand there are the most exciting times in the perspective of progress ever observed in the recorded history of mankind. All countries of the world are making the progress in almost all aspects of life. These countries are working hard to face the challenges of 21st century. The world in which we are living has become the world of information and technology. The old concept of ruling the world with power has completely changed by the disintegration of soviet union in the last decade of the previous century. The progress speeds of many countries are remarkable. China got independence two years after Pakistan but it has increased its speed of development up to a great extent. Today china is enjoying the status of world’s second fastest growing economy post Mayo, china has established an all time global record in doubling its per capita income between 1977 and 1987. According to a world Bank purchasing power parity (ppp) china has a GDP of just under $3. 0 trillions which is second largest after united states of America. If one accepts the projections of a Rand study of 1995 china will become world’s largest economy by 2010 with GDP of $11. 3 trillions. China has managed to get a complete control over the markets of many countries. Its trade abilities have captured a great foreign exchange reserve. Now china has entered in the making of such a car which may be considered very well prepared country to face the challenging environment of new millennium. It can also be said that today no effort to regulate global trade can be succeeded if china is not part of decreased exchange risk premium in interest rates and has increased investment demands. The echo of single currency swept across the world with free trade zones. Due to this wonderful success of Euro, many countries have inspired nd they also started their ball rolling in the same direction. In Holland the Dutch people have innovated such a food for the cattle which helps the cattle to grow at a very fast rate. The cattle is very important for Holland as it enjoys a great position in the export of best quality milk, butter and meat. This earns a great amount of foreign exchange for Holland. The Dutch people have also worked successfully on a particular televi sion which also provides all the facilities of a computer as well. These examples show that the Dutch people are very well prepared to face the challenges of the present millennium. The world has become a global village. The distances have been reduced up to an appreciable extent. In America the people have started a new practice. The high officials do not go to the offices. They control majority of their official matters through computers. This helps them a lot in saving their precious times which they would have wasted in travelling. The countries like Korea, Malaysia, Thailand and Vietnam are working very hard. This hard work has enabled them to face the challenges of current millennium in a very dignified way. These countries have made development up to this extent that it has become a far cry for Pakistan to assimilate whit their stands. Korea has also attained a significant position in the exporters of cars and other vehicles. In 1960’s Malaysian economy was very poor but through hard work they have strengthened their economy up to a great extent. The Malayan television and other electronic instruments have really captured the markets of many countries. These countries have achieved this position of stabilization through their appropriate economic strategies, good educational policies, sprit of patriotism and excellent foreign policies. The rate of progress in order to face the challenges of new century is also very high in India as compared to Pakistan. The Indian people have really done wonders in the field of information technology. The Indian software engineers have achieved remarkable successes. They have made exceptional innovations in this field. Indian government has provided all the possible support to their people. They have established a silicon Valley in Madras for this purpose. Through the export of software programs India is earning a great deal of foreign exchange which has played a vital role in reducing the economic distress in India. The Indian economy has become very strong. India has also been benefited from the female employment ratio in the country. The women are also working with the men in almost all the professions. The world has made progress in many fields at a massive rate. In the above mentioned facts and development made by the various countries, it can he easily analyzed that where do Pakistan stand? How Pakistan has prepared itself to face the challenges of the newly started millennium? Some efforts were also made in Pakistan to made some progress in the last decade of the previous century but those could not become result oriented due to self-centered access and sift handed complements from the advisors of the rules. The continuous change in the leadership of the country proved very harmful for the growth in all the fields. In the beginning of 1990’s the government of Nawaz Sharif took some steps in order to improve the infra structure of the country. He established the Motorway project in collaboration with the Daewoo company in order to improve the means of communication. He also facilitated the people of Narwhal with a new telephone exchange He also tried to introduce a self employment scheme in the form of â€Å"Yellow cab† in which the taxi cars were provided to the educated youngsters on very easy and affordable installments. The purpose was to enhance the employment ratio in the country but this scheme also met the failure because many of his party members utilized this scheme for their own benefit. In 1930 when Mrs. Benazir Bhutto got the rule, she started a welfare program me for general masses under the name of peoples programmed which act rally proved worthless for the people as many politicians started personal aggrandizement through this programmed. They got heavy funds which were never used for the welfare of the people. They got heavy funds which were never used for the welfare of the people. Similar nothing valuable could be done in the next turn of Nawaz Sharif. The rolling substitution of governments in the last decade proved as main obstacle in the way of progress of our country. In 1999 during the argil episode Pakistan clearly witnessed that no country was ready to support it Even our closest friend china refused to helps . This shows the failure of foreign policy. So Pakistan needs to reform its foreign policy on the following three grounds i. e. power, wealth and status. Power means the capacity of Islamabad to influence the policies of super powers towards Pakistan. Wealth means to increase the foreign exchange reserves of Pakistan . For this purpose the exports should be increased by raising the standards of our products. Status means to get a prestigious position for people of Pakistan in the world. One more important sector which needs a great attention is the infra structure. The unemployment has increased by leaps and bounds. It should be considered very seriously . The deserving and educated candidates don’t get the proper jobs. Instead of deserving candidate don’t get the proper jobs. Instead of deserving candidates there is often a square peg in the round hole which frustrates the deserving youngsters. This frustration gives rise to the crime rate in the country. So the merit system should be improved. So far all the efforts to stabilize the economy and infrastructure have proved to flog a dead horse. Pakistan also needs to improve the health facilities. The efforts made in this regard are not more than a drop in the ocean. So conclude in this way that in spite of all those obstacles and slow growth rate of progress. One may hope that the time will be changed. According to the policies made by the Musharraf government it can be considered that now the time is not far when Pakistan will bear the palm. Now the time has come that if we want Pakistan to rise up to that extent which was dreamt by Quaid-e AZ am, then every Pakistani will have to work up to his entire ability and diligence. How to cite Challenges of the 21st Century and Pakistan, Essay examples