What is Modern physics: Definition and 253 Discussions

Modern physics is a branch of physics either developed in the early 20th century and onward or branches greatly influenced by early 20th century physics. Notable branches of modern physics include quantum physics, special relativity, and general relativity.
Classical physics is typically concerned with everyday conditions: speeds are much lower than the speed of light, sizes are much greater than that of atoms, and energies are relatively small. Modern physics, however, is concerned with more extreme conditions, such as high velocities that are comparable to the speed of light (special relativity), small distances comparable to the atomic radius (quantum mechanics), and very high energies (relativity). In general, quantum and relativistic effects are believed to exist across all scales, although these effects may be very small in everyday life. While quantum mechanics is compatible with special relativity (see relativistic quantum mechanics), one of the unsolved problems in physics is the unification of quantum mechanics and general relativity, which the Standard model (of particle physics) currently cannot account for.

View More On Wikipedia.org
Recent contents Top users
  1. P

    Teaching yourself modern physics

    Hello everyone, I am a software engineer by profession. However, I would love to teach myself Physics and would like to gain a deeper understanding of modern physics. I know it is quit a daunting tasks but I am determined to make it happen, even if it takes a few many years! I understand that...
  2. Z

    Finding Textbooks for Modern Physics Course Without Calculus

    Hi Everyone... I need some help. I have read everyones threads on textbooks for modern physics. I am currently writting a new course in modern physics for my high school. The problem I am having is finding a textbook, or even several smaller books that do not use calculas. I am hoping to...
  3. P

    Find the Best "Modern Physics" Textbook for Sophomore-Junior Physics

    Does anybody know of a good "Modern Physics" textbook, to be used for a sophomore-junior Physics course in Modern Physics? I had once used Krane's "Elementary Modern Physics" (long time ago) but it was not a real textbook. I have seen he has a new edition of "Modern Physics", I don't know...
  4. Saladsamurai

    Modern Physics Text: Any suggestions?

    If this is not the appropriate forum, I apologize. I just assume it is the forum where the people reading this will have the most insight on the matter. I am looking to purchase a modern physics text to study at my own pace. I have a fairly good understanding of calculus and ordinary...
  5. E

    Preparing for the GRE: Modern Physics Course

    Hello, I am taking the GRE next fall and I have taken all of the core courses except a Modern Physics class. I am kind of confused as to what "Modern Physics" is but apparently it is tested on the GRE. Can someone recommend a book that will prepare me for the GRE? I like very much the...
  6. Shackleford

    Best way to prepare for Modern Physics

    I was told by the academic adviser at the University where I will be transferring in the near future that the hardest courses are the two Modern Physics courses, along with E&M, too. What book should I read to get a headstart? She also said that the courses will be a lot faster-paced than at the...
  7. T

    Topic about masses (modern physics)

    Homework Statement If a system is composed of n particles that are freely moving is M(system)=M(total masses of particles)(sum) Homework Equations The Attempt at a Solution of course no , but these particles isn't photons or electrons my doctor didnt exacly told me what are they...
  8. N

    Modern Physics Extended Response Question

    Homework Statement A polonium nucleus of atomic number 84 and mass number 210 decays to a nucleus of lead by the emission of an alpha particle of mass 4.0026 atomic mass units and kinetic energy 5.5 MeV. (1 atomic mass unit=931.5 MeV/c^2=1.66x10^-27kg.) The atomic number of the lead nucleus...
  9. D

    Deriving the Equation for Relativistic Mass

    Homework Statement Show that d(\gamma mu)=m(1- \frac{u^2}{c^2})^{-3/2} du Homework Equations It is known that is \gamma=\frac{1}{\sqrt{{1- \frac{u^2}{c^2}}}} The Attempt at a Solution The question stated in part 1 is the precise question given in the textbook. I'm not sure...
  10. R

    Modern Physics Help: K-40/Ar-40 Atom Ratio Analysis, Age Calculation

    Homework Statement Analysis of potassium and argon atoms in a moon rock sample shows that the ratio of the number of stable Ar-40 atoms to the number of radioactive K-40 atoms is 10.3. Assume that all the Ar atoms were produces by the decay of K atoms, with a half-life of 1.25x10^ years...
  11. Shackleford

    Courses Physics department faculty advisor said Modern Physics will be hardest course

    She said it's probably the hardest course I'll take in the physics program. Right now, I'm taking University Physics I with II right after. What's the best way I can prepare for the Modern Physics courses? PHYS 3315: Modern Physics I Cr. 3. (3-0). Prerequisites: PHYS 1301 and 1302, or PHYS...
  12. P

    Modern Physics Textbook Suggestions

    Hey, I was looking for some Modern Physics textbook suggestions. While searching through the forms I found some excellent Modern Physics reference book suggestions, like some by A.P. French and the sort. What I am asking for though are actual textbooks on Modern Physics (which at my...
  13. turbo

    Is Einstein's etheric model of GR compatible with modern physics?

    As an optician, I am uncomfortable with the concept that photons sail through space on geodesics defined by the masses embedded therein. What is the problem with simple refraction, as explained by classical optics? As it turns out, there is absolutely no problem, according to Einstein. In his...
  14. B

    Testing So I flunked two exams in modern physics

    Well Actually I only flunked one of my two midterms but I know I flunked my second midterm because I did not finish on time. I'm very disheartening that I failed my two midterms because I know how to calculate the solar costant when blackbody radiation is involved and I know how to find the...
  15. P

    Modern Physics Class: Preparation for Physics Major

    I'll be transferring to a 4-yr university for this fall and the modern physics class I'm considering taking will cover thermodynamics, quantum mech, and modern physics. But at my community college I already took 3 semesters of calc-based physics, including modern physics. This class will only...
  16. S

    Modern Physics: Length Contraction

    Homework Statement A rod of length L_0 moves with a speed v along the horizontal direction. The rod makes an angle of \vartheta_0 with respect to the x'-axis. (a) Show that the length of the rod as measured by a stationary observer is given by L = L_0 [1-(v/c)^{2} cos ^{2} (...
  17. B

    Top Recommended Modern Physics Textbook for Professors and Majors

    Which modern physics textbook is most recommended by physics professors and physics majors?
  18. G

    How Does Particle Beam Angular Divergence Relate to Slit Width and Voltage?

    Homework Statement A collimated stream of particles of mass m and charge q are accelerated from rest through a potential difference of V. They fall upon a slit of width d. What is the approximate angular divergence of the beam emerging from the other side? is there anyone who help me ?
  19. C

    Philosophical and Formal Foundations of Modern Physics

    Conference "Philosophical and Formal Foundations of Modern Physics", Les Treilles, April 23-28 (organized by Michel Bitbol and Alexei Grinbaum) See http://www-drecam.cea.fr/Phocea/Vie_des_labos/Ast/ast_visu.php?id_ast=762" Monday, April 23 7:30 pm Alexei Grinbaum and Michel Bitbol...
  20. V

    What does modern physics say about uncaused effects

    What does modern physics say about "uncaused" effects The old Cosmological argument says that everywhere we see an effect like motion or change we see a cause. This is a useful way of looking at everyday things. It goes on to say that regressing they form a chain. This is something we...
  21. P

    Exploring the Pi Meson: Discovery & Impact on Modern Physics

    Hello everyone, I am a senior physics student doing a paper on the pi meson. The only real website I can find with relevant information towards it is on wikipedia. I don't really want to use that as a source because of the credibility issue which arises with wiki. So I was wondering, (even tried...
  22. T

    Confused by my modern physics class

    My lecturer is currently addressing modern physics. "we" (more like "he") solved the schrodinger equation for hydrogen, and then into all the quantized angular momentum, intrinsic momentum... now we are into quantum statistics... Seriously, I have absolutely no idea what my professor is...
  23. M

    Modern Physics, Finding wave length problem wee

    Modern Physics, Finding wave length problem! wee! Ello ello! I'm having troubles getting this table started. The directions are: Use the Bohr diagram shown below to complete the following table. Tell the wavelength and color of light emitted when the following energy level changes...
  24. A

    Doubts in modern physics photoelectric :mad: effect

    i know theses qns may look lame but my answers are not matching with the book .pls help as i have a MAJOR EXAM coming up tomorrow:eek: 1.three photons are coming out from an excited ample of hydrogen atoms with energies of 12.1 10.2 and 1.9 eV respectively then which of the following is...
  25. Robert100

    Modern Physics textbook - Suggestions?

    Back when I was in college I used "Modern Physics" by Paul Tipler. It seemed like a good book (and it helped to have a good teacher.) This book was copyright 1978 by Worth Publishers; I took it to be a 2nd edition since it was a revision of Tipler's 1969 "Foundation of Modern Physics"...
  26. K

    Laypersons metaphorical attempt to account for modern physics

    I used to love my narrow little world, I used to love how uniform and smooth everything was when it was covered in the thick and greasy lacquer of simplicity. I lived in an oil painted realm, where pragmatism ruled the day, and function dictated form. In my world substance was defined only by...
  27. V

    Consciousness as an active part in modern physics

    Hi,after some PM discussion that went into this direction and a short check, I want to persent here a summary of some of the ideas involved concerning a link between the consciously experienced subjective world and physics. First of all, it is probably interesting to find out the controversy...
  28. S

    Come help me determine how bad I choked on my modern physics test>_<

    Well, I guess I didn't do that bad, but we'll see. I'll try and remember the questions of ones that gave me trouble First and foremost, what's the most probable radial distance of an electron from the nucleus in a H atom in the 4f state? I was given R(r) I just plain wasn't sure how to...
  29. C

    Understanding Relativistic Kinetic Energy in Modern Physics

    Hi Everyone, I'm reading in my modern physics book about relativistic kinetic energy. I'm a little confused about what rule of calculus allows the following statement: KE = \int_{0}^{s} \frac{d(mv)}{dt} ds = \int_{0}^{mv} v d(mv) I see that they must be saying KE = \int_{0}^{s}...
  30. N

    Access to International Journal of Modern Physics B - Need Articles ASAP!

    Does anyone have access to International Journal of Modern Physics B? If so could you send me two articles? PM me for the articles. I could use interlibrary loan but that takes around three weeks to get the articles. Thanks
  31. M

    Tipler and the 4th edition modern Physics book

    I had a couple of questions from the modern physics book 4th ed. by tipler. I can't seem to solve some of the problems and some just don't make sense to me. Chapter 4, problems: 16, 38, 43, and 49 are the ones in question Any help would be appreciated Thank you...
  32. A

    If someone has the 6th edition of modern physics by arthur beiser

    could you explain to me what is the meaning of problem 39 on pg 51? I'm not very good with computers, so i don't know how to attach the picture associated with the problem... sorry about that!
  33. A

    Studying Modern Physics Books: Textbooks for Physics Majors

    If a person were a physics major, what books or textbooks would that person read?
  34. R

    Looking for a syllabus for Tiplers Modern Physics

    I'm going to be self-studying Tipler's modern physics over the summer. I just got the third edition for $7.71 off eBay and it's in pristine condition :) I am trying to find a detailed syllabus instead of me reading every page and doing every problem.
  35. A

    Modern physics - photon problems

    Anyone know how to go about solving the following two problems? - What is the minimum frequency photons need to knock an electron out of a copper target? - If a beam of photons with 3 times the frequency of the photons from the first problem strikes a copper target, at what speed will the...
  36. R

    Where to take Introductory Modern Physics online?

    Where to take "Introductory Modern Physics" online? I missed taking "introductory modern physics" this semester and need it for my junior classes. Does anyone know of an institution that has an online class for it? Or I would even study it independently and take a test on it. Help!
  37. R

    Courses Is Modern Physics course hard?

    Is "Modern Physics" course hard? Is "Modern Physics" course hard? It's a 3 Credit course that deals with special relativity, atomic structure etc. Would it be impossible to study for this on my own to test out of it?
  38. I

    How Much Mass Does an Electron Gain at 500 MeV Energy?

    How much mass does an electron gain if it is accelerated to an energy of 500 MeV? My solution: I am using the mass of the electron in terms of "energy units"... that is m_e = 0.511 MeV/c^2 where c is the speed of light. The total energy is E = Eo + ke, where ke is kinetic energy...
  39. G

    Explaining a Paradox in Modern Physics

    i didn't quite understand the resolution to this paradox as explained by my modern physics book. in case anyone hasn't heard of this, let me explain the setup. there is a right angled lever (with arms of equal length) which is constrained to rotate about its bend point. in addition, there are...
  40. M

    Understanding Relativistic Collisions: Physics Question and Solution Explained

    A particle of rest mass m is accelerated to a kinetic energy K in a nuclear reactor. This particle is incident on a stationary target particle, also of rest mass m. a) Show that the speed of the centre of mass (that is the speed of the frame in which the total momentum is zero) is \gamma...
  41. M

    Exploring Modern Physics: Wave-Particle Duality & Photon Mass

    I was reading in one of my books today. It brought up an answered that I had when I was talking Modern PHysics over a year ago. Sadly our curriculum didn't really allow for us to do modern physics but our class flew through all the old physics for grade 12. Basically I had read a lot of...
  42. M

    Solving for the Energy and Direction of Emitted Photons from a Moving Pion

    The neutral pion is an elementary particle of the meson family that has a rest mass energy of 135 MeV. This particle is unstable and decays into two photons ("light particles" of no rest mass and energy E=pc). Consider now the following situation: a neutral pion has a kinetic energy of 270 MeV...
  43. K

    Modern Physics by Serway: Reviews

    Has anyone ever used Modern Physics by Serway? Is it any good?
  44. M

    Exploring Neutron Decay: Understanding Einstein's Mass-Energy Relationship

    The free neutron is known to decay into a proton, an electron, and an antineutrino v' (of negligible rest mass) according to n-->p+e+v'. The decay products are measured to have a total kinetic energy of 0.781+/-0.005 MeV. Show that this observation is consistent with the excess energy predicted...
  45. M

    How Is Energy Calculated in a Perfectly Inelastic Collision Between Protons?

    Hello Everyone, Can you please help me with this problem. I am not looking for a complete solution to it, I just need a few guidelines on how to proceed. Here it is, Let us consider a perfectly inelastic collision between two protons: an incident proton with mass m, kinetic energy K, and...
  46. M

    Where Can I Find a Comprehensive Solved Problem Resource for Modern Physics?

    I am looking for a solutions manual or a book that has a lot of solved problems in modern physics. If anybody knows can you please recommend it to me. P.S. The book I am using now is Modern Physics by Serway, Moses, Moyer. Thank you
  47. M

    Covariance of the Wave Equation in Modern Physics: A Proof

    Question: Show that the wave equation is in not covariant with respect to Gallilean transformations, given the function y=Asin(2pi(x/lambda - ft)) My main question is inorder to show the covariance of a law, should I apply the law on the primed variables and show that it is satisfied by...
  48. Loren Booda

    What are the gods of modern physics?

    The Big Bang is like the Old Testament creation from the void, or a Brahma day, whose cycle is 4,300,000,000 years. Quantum physics might be likened to the yin-yang duality, a Pandora's box, or the genie in the bottle. The beauty experienced sometimes while studying physics can seem like a...
  49. R

    Are These Modern Physics Books Worth Reading?

    What do you think on the value of these two entertaining books on Modern Physics by George Gamov: "Mr Tompkins in paperback" and "One, Two, Three...Infinity". They make the modern concepts like special and general relativity, quantum physics, 4D space, etc., very understandable for beginners.
  50. C

    When do clocks on an airplane and on the ground differ by 1.0 s?

    Say a jet is flying at 300mph. How much time must pass before a clock in the airplane and one on the ground differ by 1.0 s? I know that this deal with time dilation and the special theory of relativity, yet I have no idea on how to get started.
Back
Top