Modern physics Definition and 256 Threads

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.

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  1. M

    Perception of faster than light travel?

    I'm currently taking a modern physics course, I came across this problem which really threw me off guard: Three spaceships A, B, and C are in motion as shown in the figure. The commander on ship B observes ship C approaching with a relative velocity of 0.83c. The commander also observes ship A...
  2. G

    Modern Physics - Work Energy Theorem

    Homework Statement The work-energy theorem relates the change in kinetic energy of a particle to the work done on it by an external force: \triangle K = W = \int F\, dx . Writing Newton's second law as F = \frac{dp}{dt} , show that W = \int v\, dp and integrate by parts using the...
  3. J

    Is the simple explanation of modern physics ever the case?

    In QM for example, I realize it is pointless to try and picture what is happening because the is nothing macroscopic to base it on. In GR, we are told that something called space-time is curved which creates the phenomenon of gravitational force. The deeper you go into these subjects, however...
  4. G

    How Do You Determine Degrees of Freedom for Various Objects in Physics?

    Homework Statement i have a homework set to determine the degrees of freedom for certain objects. the professor never explained how to go about figuring these out and the book doesn't quite explain it well. two problems from the set are 1. a linear spring in 3space and 2. a bead constrained to...
  5. B

    What are the challenges of taking a second-year intro modern physics course?

    So my options for upper divisions this semester were pretty limited. I'm a physics major and the only upper divisions I've taken are intro thermal physics and math models. So this semester I ended up with electromagnetic theory one and modern physics. The first day of modern physics I was...
  6. F

    Questions about 'University Physics with Modern Physics (13th Ed)@

    Hi, Does anyone have any experience with the international edition of the above textbook? I got my reading list out today and almost had a heart attack at the price of the standard edition, so I had a look at the international edition. It looks good but I read that some STEM international texts...
  7. P

    So do you think using modern physics creates new areas in mathematics?

    Hello people, I just joined the physics forum and it's great to see that they're other physics enthusiasts on the internet! The reason why modern physics is appreciable for me is that it creates new areas in mathematics like this for example brought up from Michio Kaku... "String theory...
  8. C

    Engineering Engineering that deals with modern physics

    Hello everyone, I'm currently an undergraduate student who just completed his first year in mechanical engineering. The reason I'm making this thread is because I'm not satisfied with learning classical physics. I'd also like to learn and apply modern physics as well. Because of my...
  9. S

    Time it takes to transmit signal to satellite (modern physics)

    Homework Statement A communication satellite is orbiting 36 000 km above Earth’s surface. Two cities, 3500 km apart are transmitting to and receiving signals from each other. Find the time required to transmit a signal from one city to the other. They are equidistant from the satellite. h...
  10. S

    Quasi-Mathematical Books on Various Topics in Modern Physics.

    Can someone provide me with a quasi-mathematical introductory text to quantum field theory ? Ideally, a book that's somewhere between popular science and an introductory freshman physics text. I have a strong background in calculus, having just completed a one-semester equivalent reading of...
  11. E

    Is E&M a Prerequisite for Modern Physics?

    I want to take modern physics next semester but I haven't taken E&M yet. Will this be a problem?
  12. S

    Modern Physics - velocity of electron accelerated through 6 Mev

    Modern Physics -- velocity of electron accelerated through 6 Mev Homework Statement Electron accelerated through 6 Mev. from rest. My Answer was > speed of light Homework EquationsThen our professor told us to not conserve KE only as mass was increased. Therefore use einstein's e=mc^2. The...
  13. S

    Exploring A.K. Ramanujan's Mathematics for Modern Physics

    So, recently i found out that Ramajuan's math is highly applicable and usable in modern physics(things like string theory and stuff) so i decided to start learning more about his work and i stumbled on some questions. 1.What kind of math background do i need before diving into Ramajuan's work...
  14. L

    Modern Physics Lab: Hydrogen Wavelengths & Energy Levels

    This question is based on a modern physics lab I'm working on, and it's conceptually killing me. 1. Homework Statement For hydrogen, compare your measured wavelengths to the predicted wavelengths for hydrogen. Assuming the lower level is the same for all the lines you observed in the...
  15. O

    Best way to tackle modern physics with engineering background

    Hello! I have occasionally lurked this forum and have found some really interesting discussions. I finally decided to join the forum and also wanted to start off with a question. I have a bachelors degree in mechanical engineering so I have the mathematics and physics foundation typically...
  16. K

    Need help with some modern physics and mechanics questions

    Ok, so am going to post 20+ modern physics and mechanics questions, and am hoping you guys can help me with them. I study in university, and was surprised during my vacation by being told that I have a calculus and physics examination in a week. I took care of the calculus part, but I really...
  17. L

    Retake physics 1 or take modern physics?

    Hey guys, looking for some input. I've taken algebra based physics 1 (got an A-) and calc based physics 2. It's my last year of undergrad but I am planning to enter a second degree electrical engineering program in the future. Should I retake calc based physics 1 or take modern physics? Would...
  18. D

    Solving Physics Homework: Rowing Boats, Relativity, and Cannonball Velocity

    Homework Statement Persons A and B are rowing boats due east. B at .5c, and A at .7c, both relative to the earth, and are in parallel tracks 3 light seconds apart (B is north of A). A starts out behind B, but as A passes B, A throws a stopwatch straight up at .5c in A's reference frame. B...
  19. shounakbhatta

    Who is the true father of modern physics?

    Hello, Some consider Albert Einstein, some think it was Galileo Galilei, some consider that E=mc^2 formula revolutionized the entire picture of physics, some consider James Clerk Maxwell's equations of electromagnetism. I consider it was Sir Isaac Newton. Newton can be well considered as...
  20. C

    Modern physics, imaginary particle

    Homework Statement The energy level scheme for the mythical one-electron element crazyidium(the names not really relevant). The potential energy of an electron is taken to be zero at an infinite distance from the nucleus (a) How much energy does it take to ionize an electron from the ground...
  21. L

    Prerequisites to modern physics?

    So, I'm a third year electrical engineer, with a heavy interest in more advanced / theoretical / particle physics. I have a few questions actually. What more should I learn before trying to tackle special / general relativity, quantum mechanics, etc? Is there a particular order I should learn...
  22. F

    What Are the Fundamental Assumptions of Modern Physics?

    It seems to me that classically physics is based upon the idea of measurement, that the length of a meter, the duration of a second, and the mass of an object is the same for one person as it is for another. Wheeler in his Geometrodynamics further was able to express mass and time in terms of...
  23. J

    Help Me Master the G-Factor: A Serway's Modern Physics Guide

    Hello, I'm having a hard time grasping this g-factor. Why was it invented? How do you solve for it? I'm currently using Serway's Modern Physics textbook right now, and I feel like it skimped on it so much that I just have no idea what it really is. If someone can expound, it would be greatly...
  24. U

    How could one learn modern physics?

    Hi, I'm teaching myself physics and i started with Physics For Scientist and engineers 6th edition Tipler standard edition (without modern physics chapters), and I'm now finished of it and wish to begin learning modern physics. What is the best modern physics textbook that should i study?
  25. L

    Mathematics used in optics and intro to modern physics

    Hello. I am taking intro to modern physics and optics next semester, the intro to modern physics is a 300 level class and the optics course is a 500 level class, at Wayne State University. I want to come into next semester very well practiced in the math needed for those classes. Could...
  26. R

    Kenneth Krane's Modern Physics muon example (SR)

    This is the frirst SR problem in his book. I think the question is flawed. The solution assumes a speed of 3.00 E8 m/s to calculate Δt=333us since it traveled 100km. Next, 333us and 2.2us is used to solve for velocity using the time dilation formula. Velocity is reported to be .999978c.This...
  27. R

    Modern Physics Momentum and Trying to find the Direction of Decayed Particles

    Homework Statement A kaon (denoted K0) is an unstable particle of mass 8.87 × 10−28kg. One of the means by which it decays is by spontaneous creation of two pions, a π+and a π−. Both the pions have a mass of 2.49 × 10−28kg. Suppose that a kaon moving in the +x direction decays by this process...
  28. O

    Modern Physics Qs - Time Dilation & Relativity

    Q1. Time Dilation Question Homework Statement Three identical triplets leave Earth when they reach the age of 21, in the year 2121. Each triplet goes on a spaceship journey that takes T years, as measured by a clock in each spaceship. During the journey they travel at a constant speed v, as...
  29. Y

    How Do Velocities Combine in Relativistic Physics?

    Homework Statement Spacecraft 1 is launched from the surface of the Earth with a velocity of 0:6c (Earth RF) at an angle of 50 above the horizontal +x axis. Spacecraft 2 is moving with a velocity of 0:7c (Earth RF) in the x direction towards Spacecraft 1. Determine the velocity and speed of...
  30. arupel

    The Kantian Wall - The Meaning of Space, Time, and Mass in Modern Physics

    Some things have extreme simplicity, but because they sideways of our vision, they are unnoticed. Some things are so obvious, so close to us that they are almost invisible. This is a philosophical, not a scientific essay. It initially began as an exploration of belief, based on skepticism...
  31. R

    Current state of play in modern physics for the dim

    Not really sure I have the right forum for this but here goes. This is for self education and nothing more. When I left school (25 years ago) I thought I understood physics. Since that time physics seems to have exploded. Particles have got smaller, string theory has appeared in the public...
  32. R

    Please recommend the best book on Modern Physics.

    Please recommend Modern Physics book which is good for a student. Not taking a course about the subject. I don't agree with comments like get a book for each subject. I want to know Modern Physics at level of sophomore. Is there a book like Griffith's Electrodynamics or Halliday's Fundamentals...
  33. majormuss

    Modern Physics (S. Theory of relativity) problem

    Homework Statement Find the force necessary to give a proton an acceleration of 1.0 10e19 m/s2 when the proton has the following velocities (along the same direction as the force). Homework Equations P=mλu The Attempt at a Solution Found the derivative of the above equation and...
  34. O

    Quantum Physics without taking Modern Physics

    Hello everyone! I recently have transferred to a 4-year institution from a 2 year community college. Unfortunately, my community college did not offer Modern Physics and so I did not take the course. I am currently trying to pursue a B.S. in Physics and it requires me to take Quantum Physics...
  35. PhizKid

    Book for introductory Modern Physics?

    This is for a 2nd year undergraduate course at community college. The course description says it covers: atomic and nuclear physics, relativity, space physics, and elementary particle physics. Which book would help me through this course?
  36. M

    Modern physics basis for magnetic properties of matter

    Do you people know any decent and simple (no fancy math) material for the atomic physics around diamagnetism, paramagnetism and ferromagnetism? Topics like wave-particle duality, energy levels, solids, why metals are conductors, relation between magnetic moment and effective mass of...
  37. E

    What are some nice modern physics experiment that I can do?

    I need some modern physics experiment to be presented on science fair. I have no idea like I am thinking of particle physics like atom smashers but it's impossible to create one for just a month. The cornstarch in a stereo has been gotten by others so I am thinking of photoelectric i don't know...
  38. A

    Programs Can I opt to take modern physics as major for M.sc?

    I m presently studying B.tech 4th year,with branch as electrical and electronics engineering..Is it advisable/plausible to take modern physics as my M.sc course and go for research.? I've keen interest but is it praise worthy to do so.? Since I ve a background of electrical and electronics...
  39. U

    Complicated, or just tricky, modern physics problem

    This is not homework, my friend sent this to me randomly and told me to solve and idk... "A pogo stick, ****ing one sideways, is oscillating at a frequency of 700 THz with a negatively charged particle emitting a photon which then collides with a photoelectric cell with a negligible work...
  40. H

    Self-Study Textbook for Modern Physics

    Guys i need an easy to understand Modern Physics Book. I am planning to complete the course on my own in summer break, so that when my university reopens i could take an extra course without any extra burden. Here is the course website, Please make 2 or 3 suggestions based on the course...
  41. GreenAce92

    What should I have learned in Modern Physics?

    My final exam is in 5 days. Our professor informed us that he would not test us on Chapter one which is your Lorentz transformation, length contraction, basic relativity stuff. But then we go all the way up to I believe chapter 7, so 6 chapters. The thing is, we go into Psi wave...
  42. P

    Dissociation Energy (Modern physics)

    Homework Statement Hello, the question is, does the binding energy of a molecule is greater than or equal to the dissociation energy? Homework Equations A molecule exists because its energy is less than that of the system of separate noninteracting atoms: Mc²∠Ʃ mi c² Here M is...
  43. A

    Physics Any research topics for a undergraduate student in modern physics?

    I ve browsed many sites and wasted most of my time for finding a better topic but most of my friends managed to publish papers in there interested topics(other than modern physics)..I m really desperate to publish a paper since its getting late..Can anyone please suggest a better topic in modern...
  44. fluidistic

    Modern physics, quantum numbers, subshells

    Homework Statement Find all the terms of an atom whose last subshell is np³.Homework Equations M_L=\sum _i m_{l _i} M_S=\sum _i m_{s _i} The Attempt at a Solution My professor did the same exercise but with np². Basically he wrotes all the possible quantum numbers for the atom: 1)m_l=1...
  45. S

    Modern Physics in the Highschool Curriculum

    I don't know if this should go here exactly, excuse me if it goes in another place. So I am learning about Quantum Mechanics and Relativity in this moment. These ideas are 100 years old or less. This makes me think, when did this ideas got incorporated in the academic curriculum? Was it...
  46. 1

    Which college offer Light and modern physics in summer?

    Hello, I'm looking for a college that offers Physics 4C(or equivalent classes) in this coming summer in CA or nearby states. I did a lot of research, but i didn't find anyone offers it in summer. I have to take it before the fall semester starts. Here is the course description Physics 4C...
  47. M

    Modern Physics view of Length Contraction?

    I've been told several times that length contraction is not "real" in the sense of material or its space actually contracting. How does modern physics (by that I mean what is being taught currently) view Bell's spaceship paradox. Will the string break? Why, if length contraction is not real...
  48. M

    Name Of A Good Book (Modern Physics)

    I just need a thorough explanation for schrodinger's equation, in a healthy way. Am aiming to learn it alone. I thought Schaum's series will do it, but it didn't. If you please give me the name of a good book, I would be more than grateful. Regards, M. next
  49. A

    Relativistic Mass as described by Kenneth Krane in 'Modern Physics'

    Homework Statement Mr. Krane describes this scenario in a presentation of relativistic mass in his book Modern Physics John Wiley & Sons, Inc. 1983 p. 36-37 According to one observer, two balls of equal mass, m1 and m2, are approaching each other at equal speed, v. The proper mass of...
  50. S

    Project ideas for modern physics class

    Greetings, First of all I believe this is the right forum as it isn't necessarily homework but more of a discussion about possible projects/experiments for a modern physics class. If it is in the incorrect forum could a mod please move it. I am currently taking a physics 3 course that...
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