Hc Verma Quantum Physics
Егор Ульянов
These names refer to four prominent scientists who have made significant contributions in the fields of physics and astronomy. They have published numerous papers and books that have advanced our understanding of the universe.
Hrw and hrk are known for their work in theoretical physics, specifically in the fields of quantum mechanics and particle physics. Verma has made groundbreaking discoveries in the field of astrophysics, while Freedman is a renowned cosmologist.
These scientists have contributed to our knowledge of fundamental particles and forces, the nature of space and time, and the origin and evolution of the universe. Their work has helped shape the current theories and models in physics and astronomy.
Hrw and hrk have received numerous awards and recognition for their contributions to physics, including the Nobel Prize in Physics. Verma has been part of several groundbreaking studies in astrophysics, and Freedman's work on the expansion rate of the universe has been hailed as a major breakthrough.
Yes, these scientists continue to be actively involved in research and have collaborated on various projects with other prominent scientists in their respective fields. They also mentor and inspire the next generation of scientists through their work and mentorship.
The Presidential Early Career Award for Scientists and Engineers (PECASE) is the highest honor bestowed by the United States Government to outstanding scientists and engineers who are beginning their independent research careers and who show exceptional promise for leadership in science and technology.
Established in 1996, the PECASE acknowledges the contributions scientists and engineers have made to the advancement of science, technology, education, and mathematics (STEM) education and to community service as demonstrated through scientific leadership, public education, and community outreach.
For pushing the frontiers of quantum physics through pioneering new devices that detect and count single particles of light, and for serving the community through professional leadership, mentoring students, and assisting disabled skiers through the Ignite Adaptive Sports program.
Dr. Mohan Lal Verma is well-known physicist and material scientist, having pioneered work on computational material modelling in India.
He is currently working as Professor and Head of the Department of Applied Physics at SSTC and works closely with students and Ph. D. scholars, guiding them on emerging topics and new subjects. He is also spearheading the work on quantum chemistry based software called SIESTA and is working to help Indian students and teachers become familiar with this new technology that is ready to be launched. He is a an active life member of several professional bodies like National Society of Solid State Ionic, Material Research Society of India, The Society for Advancement of Electrochemical Science and Technology, Karaikudi etc. and is passionate about contributing to scientific development though his research activities.
Dr. Verma is highly accomplished in the field of computational material physics and he works in close collaboration with the faculty of Applied Physics, Michigan University USA for various research projects.
He has published 45 research papers in national and international journals, organized several national conferences and international workshops. Having successfully completed two research projects, Dr. Verma is a highly sought after academician and scientist, who brings his expertise in computational/ mathematical modelling, Siesta and related post processing, plotting and visualization tools and Quantum Expresso. He has also worked on emerging technologies like polymeric electrolytic materials and designing electrodes in the form of nano ribbons and nano belts for different electrochemical and optoelectronic devices viz solid state battery, super capacitors organic light emitting diodes and light emitting electrochemical cells.
The central physics idea that I'm about to grossly overthink is that vampires are somehow distinguishing sunlight from other forms of light. They're perfectly capable of appearing in brightly lit rooms to attack ordinary humans, but sunlight reduces them to ash in seconds. But in physics terms, one photon is just like another. So what could possibly distinguish sunlight from other forms of light?
In physics, we can describe any individual photon of light in terms of two related numbers, the frequency and the wavelength (they're related through the speed of light-- frequency times wavelength is equal to the speed-- which is a universal constant; for this reason, physicists will frequently switch between the two, opting for whichever is most convenient at a given moment). To characterize a source of light, though, we need to know the full spectrum of frequencies it puts out-- what's the intensity of light emitted (how many photons per second) at a particular wavelength.
Most sources that generate a significant amount of light are either thermal sources or atomic line sources. A thermal source is just an object that's emitting light because it's very hot-- the heating element in a toaster, say, or the filament of an incandescent bulb. An atomic line source, on the other hand, consists of a collection of atoms of a particular element that are then induced to emit light at one of the characteristic frequencies associated with those atoms-- a neon light, or those yellowish sodium-vapor streetlights, say. For these purposes, lasers are a special case of an atomic line source-- they emit only a single narrow range of frequencies (though in the case of semiconductor lasers, these aren't actually coming from atomic states).
The light from a thermal source has a very broad spectrum, emitting a wide range of different frequencies, which might seem like a total mess, but it turns out there's a simple way to characterize these. Hot objects emit light in what's called a "black-body spectrum," a particular distribution of intensities vs. wavelength that depends only on the temperature. the physics of black-body radiation was first explained by Max Planck in 1900, and Planck's theory is what gives us the term "quantum" for a unit of energy.
So, if you're looking for a distinction between sunlight and candlelight (as Zack originally noted) or sunlight and an incandescent bulb (for more modern vampires), the key distinction between them is the temperature. A candle flame is pretty hot in human terms, but only around 2000K (reminder: Kelvin temperatures are measured starting at absolute zero, and one kelvin is one degree Celsius; room temperature is a little bit less than 300K), while a really hot light bulb filament might hit 3000K. The Sun's spectrum closely matches a black-body at something like 5600K.
What's the difference between these? Well, the peak of the black-body spectrum shifts toward shorter wavelengths as the temperature increases, which is why objects being heated glow first a dull red, then yellow, then white. So sunlight would have a lot more short-wavelength radiation than candlelight or incandescent bulb lights-- really a lot more, because the drop-off at the short wavelength end of the spectrum is extremely rapid. The spectrum of the sun extends well into the ultraviolet, while candles and light bulbs produce next to no UV light.
So, it might be just the ultraviolet light that's the problem-- one series of vampire novels by Charlie Huston has vampires exposed to sunlight dying from extremely rapid cancers caused by UV lights, which is a nod toward this feature. But, of course, if UV alone were the culprit, that would present another problem-- as we know from modern vampire movies, they frequently hunt on the dance floors of night clubs, and it's a rare nightclub that doesn't feature some "black lights" bathing the crowd in ultraviolet radiation...
So, how could you distinguish sunlight from a black light source? Well, the sun emits light over a huge range of wavelengths, where "black lights" tend toward the atomic line source end of things, so maybe you need both short-wavelength radiation and long-wavelength radiation at the same time. Maybe, vampires in sunlight are victims of a two-photon process.
If your only exposure to the idea of photons is a survey course, this might seem like an impossibility. We usually introduce the idea of photons through an experiment like the photoelectric effect, where short-wavelength light has photons with enough energy to knock electrons loose from a metal surface. When we do that in intro courses, we specifically deny the possibility of absorbing multiple low-energy photons to build up the necessary energy.
The forbidding of multiple-photon processes is a lie-to-children, though: you can, in fact, have processes where you absorb two photons at once, but they're much less likely than single-photon absorption, and thus not really relevant for the photoelectric effect. This is what makes a green laser pointer possible, though: a green laser pointer uses an infrared laser source that enters a special "doubling crystal" that can absorb two infrared photons and spit out one green photon with half the wavelength (twice the frequency). This is exceedingly unlikely to happen, and thus requires a fairly high intensity, which is why you should be careful when playing with green laser pointers: they're supposed to have a filter in them to block the vast majority of the infrared light that doesn't get absorbed, but if that filter was left out to hold down the price, they can actually be much more intense than advertised, and dangerous to your eyes.
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