Menstruation Disorders Research Paper Example | Topics and Well Written Essays - 2500 words

Menstruation Disorders - Research Paper ExampleA menstrual disorder will affect the muliebrity normal menstrual cycle, and the disorders include painful menses, abnormally heavy bleeding and lack of menses. Normal period is bound to occur during the years of puberty and menopause. withal referred to as period entails a process where blood flows from the uterus to the cervix and out of the vagina. Some women will experience emotional and physical symptoms during the time of menstruation while another will not and such factors may disrupt a womans normal life in a identification number of ways. It is essential for the reproductive-aged woman to understand their menstrual cycles and some of the orders that ar bound to occur to be able to prevent, manage them and seek medical attention. Most of these disorders perplex straightforward explanations and treatments options that exist to help in relieving the symptoms. It is essential for a woman experiencing irregularity in their cycle to seek medical attention from a healthcare profession (Peacock, Alvi, & Mushtaq, 2012). Major topics in the research paper include the menstrual cycle and its features, the menstrual disorders and their risk factors and the management and complications of the underlying disorders. The menstrual cycle is brisk and regulated by a complex surge of reproductive hormones that work together to prepare the woman body and systems ready for pregnancy. The regions of the body that control these hormones are the hypothalamus in the brain and the pituitary gland that all control six important hormones in the body.

Short listening and assignment Essay Example | Topics and Well Written Essays - 250 words

Short listening and assignment - Essay ExampleThe instrumental roles of the drums are to provide brushes on the drums. Drums are beating out a categorical beat periodically as the performance ends (Ventnor43 2012).ii. Melody statements-Melody assertions in the performance have a top arrangement. The head arrangement originates from the lateral thinking around the 12-bar blue sample that encourages the same. In the 2nd chorus, Basie controls this chorus line with a head arrangement that commences with a two-chorus icebreaker (Ventnor43 2012).4th Chorus George Hunt comes into his solo on a trombone and the timbral distinction changes from the 3rd chorus so that the disposal is soloing forthright and the reeds go together with the background (Ventnor43 2012).The name of the solo to be analyzed is the third chorus performance. This solo engages Herschel Evans coming into his solo on a saxophone escorted by riffs from the brass division. The solo was successful because it was such a po pular tune and so simply accepted (Ventnor43 2012).My emotional response is that the solo was normal for big dress circle swingers. The solo was normal between the soloing reed tone and the brass supplement. I liked the timbres because they were distinct and utilized to start out one chorus from the next. withal though Basie is not the only black artist to have endured pain this way, One Oclock Jump pulls it out the best (Ventnor43

Fair trade- how good is fair trade Essay Example | Topics and Well Written Essays - 1250 words

Fair trade- how good is fair trade - Essay Exampleonly do they feel penalised for having saved, they in any case pay a gift for being capable of meeting their own costs, and allow topical anaesthetic authorities to carry on paying less than the full costLooking for a cargon home is not easy. People are often doing so under time pressures and in the wake of huge emotional upset. So they regard as much information as possible, not least about how much it will cost. The report recommends setting up a one-stop shop specialising in care home information, and this, along with the recommendation that regulations should be amended to make clearer price information a requirement on homes, could make a macro difference for many vulnerable people. Those who are meeting their own fees will then see that the home they are considering charges self-funders more than those who are placed by local authorities. And families searching for a home for someone who qualifies for local authority suppor t will also be able to see that there are few - if any - homes in the locality that are prepared to take publicly-funded residents without recourse to the family topping-up. The need for a third party top-up often means that the price the local authority has set is insufficient to enable the home to operate.So this move towards greater transparency will go some way towards creating fair trade in care and may, for some homes, make the difference between carrying on in business or closing, making existing residents homeless and reducing choices available to future generations.I am optimistic about the scope for change and improvement. But I should not get too carried away, as there is evidence that a truly large number of people have either no contract, or one containing unfair terms. And this is despite an earlier study (OFT 1998) identifying contractual...Every one of us has likely seen reports or heard something about demonstrations against globalisation when international organi zations like the WTO meet. One example was the G8 meeting in July 2001. So we have to ask us the gesture why there are some people who protest against globalisation and also against the remedy trade the WTO stands for. The main complain and concern of these groups is unfairness. They say free trade is unfair, the low wages are unfair, the poor working conditions of foreign workers, the environmental standards in less developed countries, the high profits of multinational corporations, the diversity in incomes around the world, everything is unfair. If these reproofs are true it would mean that also free trade and globalisation is unfair. However the people of international institutions and multinational corporations who are in favour of free trade and globalisation also use the term fairness in their arguments. If a multinational company pays low wages in less developed countries, they can claim that the wages are still fair set because they are above the legal minimum wage stand ards and that the workers would not get a better opportunity in a company of their country or their government. The WTO and other international organisations consider free trade fifty-fifty as help because it will promote economic growth, which in turn will raise the living standards throughout the whole world and reduce also the income inequality in the future.

Ethical Dilemma Essay Example for Free

Ethical Dilemma EssayAll healthcare professionals take the Hippocratic Oath, in this oath it states that, I will value the privacy of my tolerants, for their problems are not disclosed to me that the world may know. (Miles, S. H. (2004) There are many different versions of this oath but the concept and meaning roll in the hay it remains unchanged. This section of the oath was designed in part to protect patients privacy. Building and establishing a relationship based on self-assurance with our patients is essential in the foundation in providing good quality care. This allows our patients to feel comfortable discussing anything with us and knowing it will be kept confidential. In nursing ethics move a critical role, breaching confidentiality keep have a magnitude of ethical takes including legal issues and patients no longer trusting medical checkup professionals. As healthcare professionals, we are faced with situations daily with an array of ethical, legal and profe ssional responsibilities where we have to use our own personal judgments to protect both our patients but the globe as well.As a legal concept, confidentiality can be said to be an obligation on one person to uphold the privacy and security measure of another persons information. This legal obligation arises in several areas under common law in contract law where these terms can be express terms or implied and as a general legal duty where it could be considered negligent if harm results as a consequence of a breach of confidence. (Cornock 2011). Confidentiality does not override ethical principles in all cases, and some cases it would be considered unethical to not break confidentiality when a legal prerequisite makes a breach mandatory.Nursing encompasses the prevention of illness, the alleviation of suffering, and the protection, promotion, and restoration of health in the care of individuals, families, groups and communities. (ANA 2010) This duty to such an extensive popula tion can irritate obvious conflicts both professionally and personally. Does the right to privacy of our patient over ride a safety concern to our community? In nursing usage nurses are able to use a variety of ethical theories and apply these to patient situations. Deontologic theories hold that you are acting rightly when you act according to duties and rights.In other words, duties and rights are the correct measuring rods for evaluating a course of action and its outcome. (Purtilo 90) People who follow this theory in their clinical practice have really consistent decisions as these are based on their duty. It becomes the healthcare providers duty and obligation to respect and protect a patients confidentiality. By breaching patients confidentiality breaks the trust that was built between patient and provider. Utilitarianism, an act is right if it helps to bring about the take up balance of benefits over burdens, in other words, the lift out utility or consequences overall. (Purtilo 92)This theory would be basing a decision on whether or not the action (breaking or not breaking confidentiality) brings out the best outcome. However, sometimes the best outcome isnt legally correct. In the article Bioethics on NBCs ER Betraying Trust or Providing Good care? When is it ok to Break Confidentiality? by Pamela Nathanson, we see a time when a healthcare provider is faced with an ethical dilemma on whether to break a patients confidentiality in order to protect the patient and the community.Like with any ethical dilemma there are steps that can be employ to help a healthcare provider make a decision or help solve the problem. These steps include 1) gather relevant information, 2) make the type of ethical problem, 3) use ethics theories or approaches to analyze the problem(s), 4) explore the practical alternatives, 5) complete the action, and finally 6) evaluate the process and outcome. (Purtilo pg 102-110) Using this process healthcare professionals are able to make decisions to tough ethical dilemmas that come up in their clinical practice.I agree with Ms. Nathanson that the parents contained to be informed of their daughters diagnosis in order to prevent harm to the patient and ensuring the patient receives proper follow up care. I also agree that the school did not need to be informed of who the student was but to inform the school that it had come to the attention of medical professionals about sex parties going on in the school. By choosing this way you are ensuring the safety of your patient and the community with causing the least amount of damage.If you disclosed to the school who the student was as the nurse did in the convey you risk unnecessary harm to your patient. Ethics committees are made up of members that include a lawyer, an ethicist, quality improvement manager, a nurse, a clergyman, a physician and an individual from within the community. By joining together these members with diverse backgrounds, experiences an d perspectives they are able to come together to help develop different alternatives and discussions regarding ethical dilemmas that may arise. They are able to help provide recommendations in complex and challenging ethical situations.However, these decisions are not law but they do hold plastered significance on influencing a judge or jury. (GCU) As long as health care deals with life and death, ethical dilemmas will come into play for medical professionals everywhere on a daily basis. Due to the nature of the medical profession, complex situations will require fast acting decisions that can be life changing for all parties involved. It is important to have a thorough knowledge of ethical theories and principles in the health care industry so medical professionals are prepared to make these decisions when they are faced with ethical dilemmas.

How Does Art and Music Relates to Each Other Essay Example for Free

How Does subterfuge and practice of medicine Relates to Each Other EssayArt and symphony bring many cultures from all around the world together. Both express thoughts, emotions, stories, views, ideas, and opinions of human life. For instance, art is a form of expression as wholesome as unison. More over, practice of medicine describe a persons culture, life, feeling and hobbies as well as art. It is how people liberty to express themselves through medicine in whichever fashion they prefer. as well as art and what people confront on a daily basis. Furthermore, art and music has change over time and it has influence in the way we dress and dance. It also reflects on violence and drugs.Finally, have an extremely negative impact on the attitudes and behaviours of American y out(a)h. Music affects society now in days by influencing teens in the wrong way. For instance, music videos have made a humongous impact on the behavior of teens. Moreover, teens flaunt their bosoms arou nd just because they see it on the videos so they portray the same image thinking that is the style. For example, Adriana, a cousin she dresses something similar to that and her response is that is what is in. Also, the way teens dance through music. For example, the songs Bring it, Donk, Ass by listening to this type of songs they start twerking dancing.In particular, a dance that teases and inappropriately moves. It consists of how you shake your behind. personality my perspectives just about those move dances are inhuman. In addition, this type of songs has made an impact on the dances and it has everybody twerking. A dance that consist of shaking hips and bottom and bouncing up and deal motion, causing to shake, wobble and jiggle . Another, huge impact would be the song and dance called The Twist it had have a tremendous impact back in the days. many people were against it but some were not.Foremost, John Johnson Jr. The Twist The Los Angeles Times, 2013) states. Soon, the fad hopped generations, sweeping up the Mad Men set of swinging bon ton men and their hip-shaking wives. Therefore, regardless if the song influences in an appropriate dance it is still going to be a big hit and it is going to have everybody dancing. Another, sociable message that is transmitting through music and art is the violence.For example, some friends would always-encountered dangerous scenes because of the designs imprinted on their clothes gang related as well as the music consisting of disrespecting others. onsequently, they were getting shoot at. In addition, my cousin Arthur was involved in the Mafia. He was kill in Mexico 3 years ago because of the music he utilize to itemisation to drugs as well as the clothes he used to were. His clothes had a picture of Mal Verde a major drug dealer. The drug music would inspire him to fight. He had a tragic death that was never solve he was kidnap and torture to death. In addition, many people are macrocosm influence in the drug l ife because of their admiration to those kinds of art as well as the music.On the other hand, it can inspire others to get out of that life style. For example, Biello, Johnson Jr. (The Twist The Los Angeles Times, 2013) states that Biello, who hope the Twist would ease his exit from the Mob, never did get out. He was assassinated in 1967, in broad sidereal day in downtown Miami. The crime was never solved but was likely part of a power struggle in the top ranks of Mafia leadership. Moreover, music and art is meant for uplifting and encouraging people yet over the years it has become degrading. Finally, the way it influences the teens today.The more aggressive the music, probably the more grumpy and sedition they tend to get. The beauty of music has exploited into evil things. For instance, the music today such as rap and hip-hop has profanity and that is the type of music that teens listing today. Consequently, can be influential, and they will try to crazy things. In conclusion, art is music it is what gives life a meaning. For example, to share ideas, express feeling, tell a grade It is what brings many different cultures together from all over the world. Weather it brings out good or bad messages it is still a form of art.

Windows 2008 Network Services Essay Example for Free

Windows 2008 Network Services EssayDHCP stands for Dynamic Host Configuration Protocol. DNS stands for Domain bring in Server. What these two concepts do is get a unique identifier known as a (MAC destination) from whatsoever computer. When the DHCP gets the MAC address from a computer it provides an IP address for that computer allowing it to access the Internet. When the computer accesses the Internet the DNS memorizes IP addresses of websites that a computer users wishes to. The reason DNS does this is because all of the websites have domain names. Domain names are translated to IP addresses. One example is Facebook. www.facebook.com is 31.13.70.81. Instead of users trying to memorize this IP Address, it exclusively makes it easier to access Facebook or even all the IP addresses that users visit. DNS makes internet surfing easier just using alphabetic letters for easy access.For two computers its not worth setting up a DHCP because when the two computers want to access th e Internet, they ordain be provided the first available IP address. If you have five computers it would be a great idea to setup a DHCP because with setting up a DHCP you could set permissions which monitors what the other computers could access the Internet for, how long they could be logged in using the Internet and their activities.Now, if there were twenty-five computers it would be perfect to have a DHCP because each computer will have its own IP Address and the IP address would never expire. Also, with a DHCP you could get permission in what any users is able to do in their specific accounts between the network computer and you are able to monitor the daily activities of each user.

The Photoelectric Effect

The photoelectric caseAssessment Task Topic The photoelectric execution1. IntroductionThe photoelectrical action is the line accustomed to the phenomenon whereby negatrons are emitted from a metal when exposed to electromagnetic beam of light of the appropriate frequency. It was first observe by Heinrich Hertz in 1887, but remained a conundrum to m some(prenominal) scientists who sought to explain it, as it clearly contradicted the accepted principles of classical physics such as James Clerk Maxwells Theory of Electromagnetic Waves. This phenomenon, inefficient to be explained by the wave model of take down, was at long last explained by Albert Einstein in 1905 with the inception of his Quantum Theory, a concept that would completely revolutionise scientific thought. The photoelectric effect has played and continues to play an important situation in mankinds scientific development.2. Discovery of the Photoelectric Effect HertzThe original observation of the photoelec tric effect go off be traced back to the German scientist Heinrich Hertz. In 1887, in an attempt to generate and detect electromagnetic radiation, Hertz created a rapidly-oscillating electric field with a high voltage installation coil to cause a visible lightsome discharge between two spherical brass electrodes. He observed that when a small length of bulls eye wire with brass spheres attached on either end was bent into a curve, leaving a small go between the spheres, and held near the sparking induction coil, a spark would jump across the gap at the same time when the brass electrodes in the induction loop sparked. This induced spark occurred despite the copper loop non being connected to any electrical flowing source. hence Hertz came to the conclusion that the copper loop was a detector of the electromagnetic waves propagated by the transmitting loop.This successful experiment was followed up by a series of others, through which Hertz show that these electromagnetic w aves could be reflected from a metal mirror, and refracted as they passed through a prism made from pitch, and then proving that these waves behaved similarly to light waves. He also turn out these waves were polarised.Through the course of his investigations, he discovered a mysterious phenomenon I occasionally enclosed the spark Bthe detector sparkin a dark case so as to more easily commence the observations and in so doing I observed that the maximum spark-length became decidedly smaller in the case than it was before. On removing in succession the various parts of the case, it was seen that the lonesome(prenominal) portion of it which exercised this prejudicial effect was that which screened the spark B from the spark Athe transmitter spark. The partition on that side exhibited this effect, not only when it was in the immediate neighbourhood of the spark B, but also when it was interposed at greater distances from B between A and B. A phenomenon so strange called for closer investigation.Upon shielding the detecting loop with glass, the intensity of the spark produced was reduced. However, when a quartz shield (a substance that allows UV jibes to pass) was applied, there was no drop in the spark intensity. He then used a quartz prism to separate the light from the transmitter spark into its various components, discovering that the wavelength which made the detector spark more powerful was in the ultraviolet range. Unable to explain this phenomenon, Hertz concluded his series of investigations in 1887, declaring that I confine myself at present to communication the results obtained, without attempting any possibleness respecting the manner in which the observed phenomena are brought about.3. Further Investigations Hallwachs, Thomson, von LenardAfter learning of Hertzs experiments, another German scientist, Wilhelm Hallwachs, devised a much simpler investigation to gift the photoelectric effect. In his own words In a recent publication Hertz has de scribed investigations on the dependence of the maximum length of an induction spark on the radiation received by it from another induction spark. He proved that the phenomenon observed is an action of the ultraviolet light. No further light on the nature of the phenomenon could be obtained, because of the complicated conditions of the research in which it appeared.I have endeavored to obtain related phenomena which would occur under simpler conditions, in order to make the explanation of the phenomena easier. Success was obtained by investigating the action of the electric light on electrically charged bodies. By placing a zinc carapace atop an insulating stand and wiring it to a negatively-charged gold leaf electroscope, he observed a slow loss of charge from the electroscope. However, when he exposed the zinc dwelling house to ultraviolet light from an arc lamp or from burning magnesium, the discharge occurred much quicker. Conversely, a positively-charged electroscope resulted in no fast leakage of charge.In 1899, British scientist J.J. Thomson finally identified that the light caused the metal come near to emit electrons. He enclosed the metal in an evacuated tube before exposing it to radiation, showing the electrons to be the same particles emitted in cathode ray tubes. ternion years later, German physicist Philipp von Lenard, who had worked with Hertz earlier in Bonn, conducted a series of experiments in which he used a bright coke arc light to examine how the nil of the emitted electrons varied with the lights intensity (see Figure 2). By using a vacuum tube, he showed that when electrons emitted by the metal plate upon exposure to light hit another plate, the collector, a small measurable current was produced. By charging the collector negatively so as to repel the electrons, von Lenard discovered that a stripped-down voltage existed, Vstop, so that only electrons with a certain energy threshold could reach the collector and thus generate a cur rent.He found that while increasing light intensity caused more electrons to be emitted (as can be gathered from an observed increase in current), it did not view the amount of energy carried by each electron, as the stopping voltage was constant. On the other hand, increasing the frequency of the light led to an augmentation in the electrons energizing energy, thus finding that for a particular frequency of light, the energizing energy of the electrons remained constant. Von Lenard also showed that if the frequency was lowered beyond a certain threshold, no current was produced, regardless of the intensity of the light. However, like the scientists preceding him, he was unable to account for these phenomena.4. Inadequacy of Classical Physics ExplanationsThe phenomenon observed during the photoelectric effect was in contradiction to classical theory explanations such as Maxwells Theory of Electromagnetic Waves which was then commonly accepted by scientists. According to such rules of classical physics, for an electron to improver enough energy to be liberated from the metal, the metal surface would have to be exposed to the light waves for a period of time. However, as observed in experiments of the photoelectric effect, the electrons were freed instantly. The Wave Theory maintains that increasing the intensity of a beam of light also increases the amplitude of the oscillating electric field vector E, thus the amount of electrons emitted should be proportional to the intensity of the light.However, according to the observations made, the current flow was independent of light intensity, yet varied according to the frequency of the light, and was non-existent when the frequency change magnitude beyond a certain level, regardless of the intensity. Von Lenards experiment confirmed the existence of a threshold frequency in the photoelectric effect, another phenomenon unable to be explained with a classical physics approach. Thus the belief in light being comple tely wavelike in nature was incompatible with the experimental observations of the photoelectric effect.5. Black Body Radiation and Plancks HypothesisA black consistency bodily cavity can be defined as a perfect cavity that absorbs all radiation that falls onto it and then perfectly radiates all energy absorbed until it is at equilibrium with its surroundings. The intensity of various wavelengths emitted by the black body changes according to its temperature, forming black body radiation curves (see diagram on right). Experimental data showed that the intensity of radiation emitted increased with decreasing wavelength, until a definite pate is reached, after which lower wavelengths of radiation are emitted at lower intensities.Yet, according to the classical wave theory of light, as the wavelength of the radiation emitted shortened, the intensity should increase, thus as the wavelength tends to zero, intensity would approach infinity. However, this would be a gross violation of t he principle of conservation of energy. Hence it remained an inexplicable conundrum for scientists for a long time, who gave this effect the name ultraviolet catastrophe.In 1900, German scientist Max Planck came up with a revolutionary explanation for this phenomenon. He made the assumption that the radiant energy may be treated statistically not as continuous waves but rather as distinct packets of energy, each of which he called a quantum. Based on this revolutionary assumption of light as particles, he formulated a mathematical equation by which this phenomenon could be exemplified. He proposed this relation that calculated the energy of a quantum for radiation of a certain frequency E= hf,Ebeing the energy in joules, fthe frequency in Hertz, and ha small constant (6.626 x 10-34Js) now know as Plancks constant. Figure 4 is a graph of experimental results that confirms Plancks equation, with the gradient equivalent to h. He proposed that any quanta of a particular frequency (and thus wavelength) would bring the same amount of energy. However, he did not attribute any physical significance to this postulation, merely perceiving it as a mathematical trick by which the corresponding answer could be obtained.6. Quantum Theory Einsteins ExplanationDue to the inadequacies of classical physics in explaining the photoelectric effect, in 1905 Albert Einstein further developed upon Plancks hypothesis to lie with up with a new ground-breaking theory to explain the photoelectric effect. He proposed that light was made up not of continuous waves but rather of discrete bundles of energy which he termed photons. He wrote in the renowned journal Annalen der Physik It seems to me that the observations on black-body radiation, photoluminescence, the production of cathode rays by ultraviolet light and other phenomena involving the emission or innovation of light can be better understood on the assumption that the energy of light is distributed discontinuously in space.Acc ording to the assumption considered here, when a light ray starting from a point is propagated, the energy is not continuously distributed over an ever increasing volume, but it consists of a finite number of energy quanta, localised in space, which move without being divided and which can be absorbed or emitted only as a whole.Einstein used Plancks equation that each photon had an energy E=hf, and proposed that light intensity was proportional to the number of photons. The higher the frequency of the electromagnetic radiation, the greater the energy carried by its photons. Einstein provided a oecumenical explanation for the photoelectric effect. When an electron is liberated from the metal surface, the energy in the light photons must be great enough to overcome the forces that bind the electrons to the surface. This minimum energy required to liberate an electron from a metal surface is known as the work ferment, represented by the symbol , and is dependent wholly on the materi al of the metal.The corresponding minimum frequency required for the photons to contain the required energy is called the threshold frequency (f0). If the energy of the photon is greater than the work function of the metal (i.e. E hf0), than the difference in their energy levels will provide the kinetic energy for the photoelectrons (electrons released from interaction with a photon), allowing them to travel and thus generate an electric current. Einsteins quantum theory explains the existence of a threshold frequency for the light below which no electrons would be emitted from the metal, an experimental observation that had puzzled scientists up to that time.Einstein established that when distinguishable metal surfaces are illuminated with monochromatic light, photoelectrons are emitted by the metal surface. The magnitude of the forces by which electrons are held varies with antithetic metals. Thus the work functions of each different metal are also varied. Below is a table of th e work functions of various metals.Figure 6Work Functions for Various MetalsSource Nave, CR. HyperPhysics Photoelectric EffectAccording to Einsteins theory a single photon collides with an electron in the metal, transferring all its energy to the electron, thus liberating the (photoelectron from the metal surface. This concept successfully explained the instantaneity of the electron emission upon light exposure, another phenomenon that classical wave theory was unable to account for.In Einsteins own words, According to the idea that the incident light consists of energy quanta one can picture the production of cathode rays by light as follows. Energy quanta penetrate into a surface layer of the body, and their energy is at least partly modify into electron kinetic energy. The simplest picture is that a light quantum transfers all of its energy to a single electron we shall assume that that happens. We must, however, not exclude the possibility that electrons only receive part of th e energy from light quanta.An electron obtaining kinetic energy inside the body will have lost part of its kinetic energy when it has reached the surface. Moreover, we must assume that each electron on leaving the body must produce work P, which is characteristic for the body. Electrons which are excited at the surface and at right angles to it will leave the body with the greatest normal velocity.Einstein formulated an equation, known as Einsteins Photoelectric Equation, to provide a denary explanation for the photoelectric effectE= hf= + Ekwith Ebeing the energy of the photon (thus E= hffrom Plancks hypothesis),the work function of the particular metal (= hf0), and Ekthe photoelectrons kinetic energy (in Joules or electron volts).Einsteins theory also explains the stopping voltage in the photoelectric effect, which von Lenard had discovered earlier. This voltage is a good measure of the kinetic energy of the photoelectrons. It can be demonstrated (see figure 7) by introducing a v ariable electric potential difference to make the anode negative, thus generating a repelling force against the photoelectrons emitted from the cathode. As this opponent voltage is increased, it will arrive at a point where there is no current flowing in the external circuit as the photoelectrons kinetic energy is not enough to overcome the voltage. This stopping potential equals the maximum kinetic energy of the electrons at the cathode, as it is just enough to stop any electron from reaching the anode.Thus EK max= -qV0, where EK maxis the maximum kinetic energy of the electron in joules, V0the magnitude of the stopping potential in volts, and q the charge of the electron (-1.60 x 10-19C). As the unit of the joule is too large to be used effectively for atomic systems, the electron volt (eV) is employed instead, with 1 eV = 1.60 x 10-19J. Thus the maximum kinetic energy of a photoelectron can be experimentally obtained from the stopping voltage. Radiation with higher frequencies wi ll result in higher stopping voltages, and vice versa.With his theory of the quantisation of light, Einstein was able to derive Plancks formula and account directly for such hitherto inexplicable phenomena as the photoelectric effect and black-body radiation. His work overturned the previously accepted, but now proven flawed, wave theory of light, heralding a new era with the concept of wave-particle duality, in which light can be seen both as waves and as particles (quanta). It was for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect that Einstein was awarded the Nobel take to be for Physics in 1921.Another notable scientist, the American Robert Millikan, expressed grave doubts about Einsteins quantum theory and set out to experimentally prove him wrong. However, after a decade of thorough scientific investigations, Millikans results confirmed Einsteins theory in every aspect. He was even able to measure Plancks constant to within 0.5% accuracy. These travails earned Millikan the Nobel look upon in 1923 and further validated Einsteins quantum theory in explaining the photoelectric effect.7. Practical Applications of the Photoelectric EffectThe principle of the photoelectric effect is utilised in some domains. One significant coat of the photoelectric effect is the solar cell. This is a device that converts electromagnetic radiation from sunlight into electrical energy. It is generally made up of a series of metallic plates facing the sun, emitting photoelectrons when struck by sunlight. These electrons then flow through an external circuit, thus generating electrical power.Another practical application is the photomultiplier tube (PMT). When light is shone onto a photosensitive cathode, electrons are emitted, and subsequently accelerated towards a second cathode. This produces more electrons, and is repeated for a number of cathodes, resulting in the propagation of the number of electrons initia lly emitted by a factor of a million, to be detected as a current pulse at the final electrode. Thus PMTs are extremely sensitive light detectors, used in scientific applications that require high levels of accuracy, such as emission spectroscopy experiments.Phototubes also moderate on the principle of the photoelectric effect. The electrical characteristics of these devices are dependent on the light that they are exposed to. Thus the current produced from a phototube may be used to operate sensor-based appliances such as automatic doors, sensor taps, alarm systems and light-activated counters.8. ConclusionThe photoelectric effect has undeniably played a significant role in the development of modern physics ever since its discovery. It has revolutionised mankinds understanding of the nature of light, its wave-particle duality. It was in the pursuit of an explanation for this phenomenon that Einstein made what was an important great rebound forward in the world of science 3/4his c onception of quantum theory. In fact the photoelectric effect and the problem of the ultraviolet catastrophe in black-body radiation formed the two experimental foundations upon which quantum theory was built.Thus the experiments conducted on the photoelectric effect can be considered among the most significant in the history of physics. Three distinguished physicists received the Nobel Prize in part for their work on the photoelectric effect Max Planck in 1918, Albert Einstein in 1921 and Robert Millikan in 1923. The observations of the photoelectric effect and its subsequent explanations by Einstein can be regarded as directly responsible for the birth of modern physics.AppendixA Timeline of the Photoelectric EffectBibliographyAndriessen, M et al. Physics 2 HSC Course2nded. Sydney John Wiley Sons Australia 2003.Burns, RW. 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