...causing them to emit visible light. The characteristic emission spectra can be used to differentiate between some elements. Different metal electrons emit different wavelengths of light to return to their respective ground states, so the flame colors are varied. These flames can be used to produce atomic emission spectra of the elements combusted. Using known values of emission spectra, one can perform a flame test on un unknown substance, gather an emission spectrum from it, and determine which elements are in the unknown substance. INTRODUCTION The smallest particle of an element that exist and still have the properties of the element called “Atom”. Electrons specify the chemical properties of atoms. Shells or energy level is the electrons in an atom that exist in layers. Usually, atoms do not eject radiation but there are ways of causing radiation to be ejected. The simplest thing to do is to heat the atoms. When an atom is heated, It soak up the energy causing its electron to get excited to positions of higher potential energy father away from the nucleus. At this point, the atom becomes shaky. Then, when an electron goes back to its ground level, it radiates the absorbed energy in the sort of light, which has a characteristic wavelength. This is the foundation of the flame test used to recognize the element. The quantity of energy absorbed will account for the presence of a spectral line. The emission spectrum may be used to observe the...
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...Spectroscopy Nature of light The Electromagnetic Spectrum General Types of Spectra Continuous Spectra Emission spectra Absorption Spectra Types of Spectroscopy How Spectrometer work? Types of Spectroscopy Examples of Spectroscopy in Astronomy Probing the Formation of Stars in Colliding Galaxies in the universe. Uncovering the mystery of quasar Spectroscopy in Astronomy camp Stars like our own Sun Bibliography 1. Introduction Spectroscopy Spectroscopy is the study of matter and its properties by investigating light, sound, or particles that are emitted, absorbed or scattered by the matter under investigation. Spectroscopy may also be defined as the study of the interaction between light and matter. Historically, spectroscopy referred to a branch of science in which visible light was used for theoretical studies on the structure of matter and for qualitative and quantitative analyses. Recently, however, the definition has broadened as new techniques have been developed that utilize not only visible light, but many other forms of electromagnetic and non-electromagnetic radiation: microwaves, radiowaves, x-rays, electrons, phonons (sound waves) and others. Impedance spectroscopy is a study of frequency response in alternating current. Spectroscopy is often used in physical and analytical chemistry for the identification of substances through the spectrum emitted from them or absorbed in them. A device for recording a spectrum is a spectrometer. Spectroscopy can be classified...
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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 discrete...
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...Sherrilyn Ling History of the Universe Lenny Tevlin October 5, 2015 6. Briefly describe the structure and size of an atom. How big is the nucleus in comparison to the entire atom? Atoms are extremely small; millions of atoms could fit end to end across a period at the end of a sentence. Protons and neutrons are found in the tiny nucleus at the center of the atom. The rest of the atom’s volume is made up of electrons, which surround the nucleus. The nucleus is very small compared to the atom as a whole, but it contains a majority of the atom’s mass. 7. What determines an atom’s atomic number? What determines its atomic mass number? Under what conditions are two atoms different isotopes of the same element? What is a molecule? The atomic number is the number of protons in a chemical element’s nucleus. The atomic mass number is the combined number of protons and neutrons in an atom. Isotopes occur when versions of an element have the same number of protons but a different number of neutrons. A molecule is formed when atoms of the same element combine. 8. What is electrical charge? Will an electron and a proton attract or repel each other? Will two elections attract or repel each other? Explain. Electrical charge is a fundamental property that describes how strongly an object will interact in electromagnetic fields. Protons and electrons attract each other, but two electrons repel. Protons have a positive charge and electrons have a negative charge; like charges repel...
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...SUBMITTED BY: JAGDEEP SINGH SECTION: C7802 ROLL No.:RC7802A21 REG. No.: 10804440 CONTENTS • • • • • Acknowledgement Introduction Laser action Einstein theory of laser Types of lasers 1. Based on energy level 2. Based on the material used • • • • Applications Recent discoveries Recent applications References ACKNOWLEDGEMENT For the completion of this term paper I would like to acknowledge my respected teacher Dr .AMRITA SAXENA who was always worthily helpful to help me in my queries in different aspects. I would also like acknowledge my friends who helped me a lot in the completion f this and were always there at one call. JAGDEEP SINGH INTRODUCTION The name LASER is an acronym for Light Amplification by the Stimulated Emission of Radiation. Light is really an electromagnetic wave. Each wave has brightness and color, and vibrates at a certain angle, so-called polarization. This is also true for laser light but it is more parallel than any other light source. Every part of the beam has (almost) the exact same direction and the beam will therefore diverge very little. With a good laser an object at a distance of 1 km (0.6 mile) can be illuminated with a dot about 60 mm (2.3 inches) in radius. As it is so parallel it can also be focused to very small diameters where the concentration of light energy becomes so great that you can cut, drill or turn with the beam. It also makes it possible to illuminate and examine very tiny details. It is this property that...
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...:RC7802A21 REG. No.: 10804440 CONTENTS • Acknowledgement • Introduction • Laser action • Einstein theory of laser • Types of lasers 1. Based on energy level 2. Based on the material used • Applications • Recent discoveries • Recent applications • References ACKNOWLEDGEMENT For the completion of this term paper I would like to acknowledge my respected teacher Dr .AMRITA SAXENA who was always worthily helpful to help me in my queries in different aspects. I would also like acknowledge my friends who helped me a lot in the completion f this and were always there at one call. JAGDEEP SINGH INTRODUCTION The name LASER is an acronym for Light Amplification by the Stimulated Emission of Radiation. Light is really an electromagnetic wave. Each wave has brightness and color, and vibrates at a certain angle, so-called polarization. This is also true for laser light but it is more parallel than any other light source. Every part of the beam has (almost) the exact same direction and the beam will therefore diverge very little. With a good laser an object at a distance of 1 km (0.6 mile) can be illuminated with a dot about 60 mm (2.3 inches) in radius. As it is so parallel it can also be focused to very small diameters where the concentration of light energy becomes so great that you can cut, drill or turn with the beam. It also makes it possible to illuminate and examine very tiny details. It is this property...
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...When light having a continuous spectrum passes through a cool gas, the resulting spectrum is: Select one: a. an absorption spectrum b. Any of the choices listed, depending on the chemical composition of the gas. c. an emission spectrum d. a continuous spectrum Which of the following features determines the resolving power of a telescope? Select one: a. The focal length of the eyepiece. b. The diameter of the objective. c. The diameter of the eyepiece. d. The focal length of the objective. Suppose that you have a (good) reflecting telescope and a (good) refracting telescope with the same diameter objective. Which one has an objective that did not require correction for chromatic aberration as it was constructed? Select one: a. No general statement can be made. b. Both c. Neither d. The reflector e. The refractor The number of sunspots Select one: a. becomes maximum near the poles. b. has been increasing since they were first recorded. c. changes with a cycle of about 11 years. d. has been decreasing since they were first recorded by Galileo. Which of the following can be detected by using the Doppler effect? Select one: a. The rotation of planets b. The radial motion of a star moving toward the Earth c. The rotation of the Sun d. The motion of binary star systems e. All of the motions listed can be detected in this manner. What keeps the Sun from collapsing due to its strong gravitational field? Select one: ...
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...objects to determine its composition, temperature, speed, and rotation of distant objects. This process is called spectroscopy. Spectroscopy was first used to study celestial objects in 1863 by William Higgins. By using this process he discovered the Sun and most stars are primarily composed of hydrogen gases. By using the spectroscopy technique it was discovered that different objects give off and absorb different spectrums of light. Where the object falls in the spectrum of light can be determined by examining its peak intensity at each wave length of light. The light helps us to determine an objects composition, temperature, and rotation. There are three types of spectra used to evaluate light. Objects which absorb light at different wavelengths are referred to as absorption spectrum. The intensity of light drops in objects which absorb light and therefore appear as dark lines on a rainbow of colors. Objects such are stars, planets with atmospheres, and galaxies absorb light and are plotted in the absorption spectra. (Col, 2010) Emission spectrum gives off light at different wavelengths. The atoms and molecules in the hot gases create extra light and produce bright lines on a black background. Comets, nebula and certain types of stars fall in these spectra. (Col, 2010) Objects whose light gives off a rainbow of colors...
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...Astronomers determine composition, temperature, speed, and rotation rate of distant objects with a tool called a spectroscopy. When a star gives off light and the light splits by prism, the spectral pattern reflects a star’s composition. All stars are 95% hydrogen, so the variations in composition expose its age, luminosity, and origin. Composition of ages can be determined by observing the light of a star. The temperature of a star can be determined from its color and its spectrum. All stars have different colors because of its light radiation. Another way to determine the temperature of a star is to examine the spectral lines in the starlight. “Because we sometimes describe light as an electromagnetic wave, the complete spectrum of light is usually called the electromagnetic spectrum” (Bennett, Donahue, Schneider, and Voit, 2009). This is used to explain all types of electromagnetic energy that exist throughout the universe. Spectra consist of three different types: continuous, emission line, and absorption. Emission and absorption lines tells us that each type of atom, ion, or molecules obtain a rare set of energy levels. Every atom has its own rare spectral fingerprint because it has its own rare set of energy levels. If matter is made of hydrogen,...
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... 2. What are the types of waves given off by the sun and other stars? Which of the visible light waves are given off by the sun? How do we known this? (Hint: Have you ever seen a rainbow?) How are these waves different? 3. How are frequency (v) and wavelength (λ) related for a wave? 4. a. What is the wavelength of the scarlet red light waves reflected from Jennifer Lopez’s lipstick in the limelight if they have a frequency of 4.25 x 1014 sec -1? b. If she happened to be feeling blue and wore her indigo eyeliner that reflects light with a wavelength of 4.15 x 10-7 m in a dimly light lit alley, what would be the frequency? 5. Explain the difference between a continuous spectrum and a line-emission spectrum? 6. a. How did Max Planck explain the relationship between frequency and energy of electromagnetic radiation? What mathematical equation did he drive to describe this relationship? What is Planck’s constant equal to? b. “One” by the band U2, the number one song voted by the listeners of 91X in 1992, can still be heard broadcasted from the booster station XTRA (“equis,tay,eddie, ah…Baha, California, Mexico”) at least once a day in San Diego. What is the energy of these waves if they arrive here with a frequency of 1.35 x 1012 sec -1? 7. Erwin Schrödinger is a man of tremendous credit to the development of the explanation of the configuration of electrons in atoms...
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...In 1913 Bohr proposed a hydrogen-atom model that linked the atoms electron to photon emissions. He also concluded that electrons orbit the nucleus of the atom; this dictates the energy level of the atom. Also in the orbit the electron does not gain or lose energy, but the electron can move between energy levels and photon energy id the difference between those levels. This explained the hydrogen emission- line spectrum, which is when a narrow beam of emitted light of hydrogen, with an electrical current, was shined through a prism and produced four colors of the visible light spectrum. (Some where infrared and others where ultraviolet) However with all of this information Bohr’s theory still lacked to explain the spectra of atoms with more than one electron, or the chemical behavior of...
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... Which of the following is true for CO2? |CO bond|CO2 molecule| A.|Polar|non-polar| B.|non-polar|polar| C.|Polar|polar| D.|non-polar|non-polar| (Total 1 mark) 6. The molar masses of C2H6, CH3OH and CH3F are very similar. How do their boiling points compare? A. C2H6 < CH3OH < CH3F B. CH3F < CH3OH < C2H6 C. CH3OH < CH3F < C2H6 D. C2H6 < CH3F < CH3OH (Total 1 mark) 7. What is the correct number of each particle in a fluoride ion, 19F–? |protons|neutrons|electrons| A.|9|10|8| B.|9|10|9| C.|9|10|10| D.|9|19|10| (Total 1 mark) 8. Which statement is correct for the emission spectrum of the hydrogen atom? A. The lines converge at lower energies. B. The lines are produced when electrons move from lower to higher energy levels. C. The lines in the visible region involve electron transitions into the energy level closest to the nucleus. D. The line corresponding to the greatest emission of...
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...Chapter 1: Our Place in the Universe 1.1 Our Modern View of the Universe * Geocentric universe: Earth-centered * Solar system: the Sun and all the objects that orbits it * Our solar system formed 4.5 billion years ago * Galaxy: great island of stars in space, having from a few hundred million to a trillion or more stars * Milky Way Galaxy contains more than 100 billion stars; our Milky Way is in the Local Group * Galaxy cluster: collection of galaxies bound together by gravity. Small collections (up to a few dozen) are generally called groups, while larger collections are called clusters * Supercluster: gigantic region of space where many individual galaxies and many groups and clusters of galaxies are packed more closely together than elsewhere in the universe * Universe (cosmos): the sum total of all mater and energy * Observable Universe: the portion of the entire universe that can be seen from Earth * Universe is expanding, Big Bang occurred 14 billion years ago * Planet: moderately sized object that orbits a star and shines primarily by reflecting light from its star; an object is a planet if it (1) orbits a star, (2) is large enough for its own gravity to make it round, and (3) has cleared most other objects from its orbital path * Dwarf planet: object that meets the first two criteria but not the third, like Pluto * Moon (or satellite): an object that orbits a planet * Asteroid: a relatively small and rocky...
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...vasilisg@mit.edu 6.638 Term Paper Attosecond Pulse Generation Abstract: The word “attosecond” (1 as = 10-18 sec) entered the vocabulary of physics when sub-femtosecond pulses of UV/XUV light were established. High harmonic generation (HHG) is currently the only experimentally proven method for generating attosecond pulses. Attosecond science has opened the door to real-time observation and time-domain control of atomic-scale electron dynamics. In this work, we review the essentials of the generation of attosecond pulses and we mention the applications of attosecond science in the control of electronic motion. 1. Introduction The need for finer time resolution and the quest for higher peak power explain the continuous trend towards shorter laser pulses since the invention of the laser. The historical progress of ultra-short technology is summarized in Figure 1. The first pulse lasers had duration of several hundreds of microseconds. The invention of Q-switching (Hellwarth, 1961) reduced the pulse length to 10 ns (four orders of magnitude decrease). The invention of laser mode locking (DiDomenico, 1964; Hargrove et al., 1964; Siegman, 1970) accompanied by broad gain laser media (Shank and Ippen 1974) further reduced the duration to less than 1 ps (another four orders of magnitude decrease). The ring cavity with intra-cavity prism compensation of the group velocity dispersion produced pulses of 6 fs (Fork et al, 1987), causing a further three-order reduction...
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...Fig. 5. Simplified block diagram of the test setup for assessing the absolute and relative pulse response of the measuring receivers The RF generator provides a continuous wave signal at the different frequencies selected for bands C and D. Then, the AWG produces the gating signal that modulates the carrier by switching on and off the CW signal, creating a pulse according to CISPR16-1-1 requirements. Finally, the modulated pulse is feed directly to the EMI measuring receiver. The amplitude of the CW signal and the gating duration are defined in Table IV for bands A to D. TABLE IV. REFERENCE PULSE DURATION AND AMPLITUDE SPECIFICATION Frequency Band Td (μs) Urms (mV) A 100 95,5 B 2,2 101,6 C 0,167 186,3 D 0,167 186,3 The specific carrier frequency...
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