Bibliography Definition Theories are formulated to explain, predict, and understand phenomena and, in many cases, to challenge and extend existing knowledge within the limits of critical bounding assumptions. The theoretical framework is the structure that can hold or support a theory of a research study.
Sample Research Papers Quantum theory, the modern physical theory concerned with the emission and absorption of energy by matter and with the motion of material particles, is one of the most important theories devised in the 20th century.
The theory is revolutionary as it replaces classical physics in the description of events at the microscopic level and now the theory provides the foundation for modern physics and chemistry. The person who formed the basis of the quantum theory was Max Planck. In the 19th century, scientists used laws of classical physics to explain the relationship between matter and energy.
Toward the end of the 19th century, various experimental results were obtained that could not be explained by classical physics. One of the failures of classical physics was the inability to explain the observed frequency distribution of radiant energy emitted by a hot blackbody.
Classical physics predicts that when a blackbody is heated, the frequencies of the light radiated will take on a continuous range of values from zero to infinity. However, from experimental observations, the frequency distribution reaches a maximum and then falls off to zero as the frequency increases.
InMax Planck announced a theory to explain the observed frequency distribution of blackbody radiation. Planck called this definite amount of energy a quantum of energy.
In classical physics, energy is a continuous variable. In quantum physics, energy is quantized, meaning that energy can take on only certain values. After Planck announced his theory, Albert Einstein applied the concept of energy quantization to the explanation of the experimental observations in the photoelectric effect.
The photoelectric effect is a phenomenon when electrons are ejected from a substance exposed to electromagnetic radiation. According to classical physics, the average energy carried by an ejected electron should increase with the intensity of the incident radiation and not the frequency.
However, from experimental observations, the energy of electrons ejected depends on the frequency of the incident radiation. Increasing the intensity of the incident radiation would only increase the amount and not the average energy of the electrons ejected.
Also, for every substance irradiated, there is a threshold frequency below which no electrons are ejected irrespective of the light intensity. He proposed that besides having wavelike properties, electromagnetic radiation can be considered to consist of individual quanta, called photons, which interact with the electrons in the substance like discrete particles.
The threshold frequency is explained by the different nature of the materials. For each material there is a certain minimum energy, called the work function F, necessary to liberate an electron.
When hydrogen gas is heated, the hydrogen atoms emit electromagnetic radiation of only certain distinct frequencies.
During toRydberg and Balmer independently found an empirical formula, called the Rydberg equation, which correctly reproduces the observed hydrogen atom spectral frequencies. However, there was no explanation for this formula. Meanwhile, inRutherford introduced his atomic model, a dense, positively charged nucleus surrounded by a revolving, negatively charged electron cloud.
In his theory, Bohr postulated that the electrons can only revolve about the nucleus in fixed orbits of different energy values, such that the angular momentum of the revolving electron are quantized.
When an electron is in an allowed orbit, the atom does not radiate energy. Such an electron is said to be in the stationary state and it has a certain amount of energy.
If the electron makes its transitions from one energy level to another, photons of energies corresponding to the difference between the initial and final energy levels are emitted or absorbed. This gives rise to the set of characteristic line spectra and the Rydberg equation can finally be explained.
A key idea towards resolving these difficulties was advanced by Louis de Broglie in De Broglie obtained this equation by reasoning in analogy with photons.
At speed c, a photon has a nonzero mass m. Inhis hypothesis was experimentally confirmed by Davisson and Germer, who observed diffraction effects when an electron beam was reflected from a crystal of nickel.
Since then, similar diffraction effects have been observed with neutrons, protons, helium atoms, and hydrogen molecules, indicating that the de Broglie hypothesis applies to all material particles, not just electrons. After the s, more and more observations were found to prove the validity of the quantum theory.
Since then, science never looked back, as the quest for the understanding of how everything works continued… You can also order a custom essay, research paper, term paper, thesis or dissertation on Quantum Theory from our professional custom writing service which provides students with high-quality custom papers written by highly qualified academic writers.Research Papers on Evolution.
Sackler Colloquium on Two Centuries of Darwin. Two Centuries of Darwin is the third collection of the In the Light of Evolution series. Each installment in the series explores evolutionary perspectives on a particular biological topic that is scientifically intriguing but also has special relevance to contemporary societal .
Theory-guided research paper. Purpose: This assignment helps the student to meet the following course objectives: 2. Evaluate and summarize professional nursing literature which supports theoretically • You are asked to read and critique a theory-guided research article and explain how the nursing theory relates to the research conducted.
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To write a decent research paper on the topic you must know that to this day, Max Weber’s bureaucracy approach has remained a highlight of the organizational theory. In the sixties, this approach found its way into the business organization theory.
This paper sketches the main lines and introduces the first results of a theoretical and empirical research set within the framework of Neurofilmology and focused on the Subjective Experience and Evaluation of Moving Image Time (SEEM_ IT).
Just as a research problem in your paper requires contextualization and background information, a theory requires a framework for understanding its application to the topic being investigated. When writing and revising this part of your research paper, keep in mind the following.