fields

  1. M

    Electric fields

    An electron moving to the right at 0.01c enters a uniform electric field. If the electron is to be brought to rest in a space of 4.0 cm, what is the direction and strength of the electric field? I've tried solving using initial energy, the resulting field strength seamed very small, any...
  2. I

    fields and photons?

    If photons travel in straight lines and do not interact with electric or magnetic fields. How can magnetic fields and electric fields be propagated by photons??? ie magnetic fields can both repel and attract depending on polarisation. Electric fields can depending polarity attract or repel...
  3. A

    Gravitational and Electric fields

    Question. The sun exerts a gravitational force of 1.64 x 10^21 N on Mars. Calculate the mass of Mars. [ Mass of the Sun = 1.989 x 10^30 kg. Mean seperation of Mars from the Sun = 2.279 x 10^11 m.] Can anyone help me with this?
  4. L

    Can a Thruster that uses geomagnetic fields and superconductors generate lift?

    Can a thruster using geomagnetic fields and superconductors generate a thrust? As shown in the figure, the thruster is equipped with a geomagnetic field convergence layer, which is a superconducting material. The geomagnetic field convergence layer repels and blocks the magnetic flux of the...
  5. G

    Magnetic forces and Magnetic fields Homework (in need of help ASAP)

    hi! I really need help in solving this problem. i do not know hot to get the y and z components of the magnetic field vector. who can help me please? A 2.5 nC particle of mass 5.25x10^-6 kg moves through a uniform magnetic field of 7.5 T directed down at 30 degrees in the y-z plane. find the...
  6. L

    Quantum fields

    You have stated that quantum field exists in all of free space but how is that possible since these are quantums that have a discrete structure; therefore, in the spaces between the particles (quantum) it would be empty which cannot be depicted as existing in all of free space. Also, you made a...
  7. TyrannosaurusWreck

    Net Electric Fields

    I keep getting this problem wrong- Two charges, q1 = −3.00 mC and q2 = 4.50 mC, are located at −2.00 cm and 3.00 cm on the x axis, respectively. What are the magnitude and direction of the resulting field at (a) x = −3.00 cm? (b) x = 0 cm? (c) x = 5.00 cm? My physics book doesn't bother...
  8. TyrannosaurusWreck

    Electric Fields

    Can anyone explain how to find electric fields caused by multiple charges at a specified position? I keep getting wrong answers when I try to do those problems, if someone could just break down how to go about them it'd be a big help! Thanks!
  9. M

    How can I measure high magnetic fields?

    Hello! I've made a lot of research about measurement of high magnetic fields - such us 1T - 2T and I can't find sensors for this range. I'm looking for a hall sensor with which I will be able to measure 1T magnetic field with good accuracy - about 0.1 mT. Do you know about anything like that...
  10. B

    Can AC Generator work with Repelling Magnetic Fields ?

    Hi Everyone, I have 4 scenarios in question . Will The EMF(Voltage) magnitude be the same in all of the scenarios? - the difference between the two photos are in the polls: one repel one attract . - i understand that the current(amps) will change between scenario 1,2 and 3,4 due to the...
  11. P

    Magnet/Elec fields (RHR)

    Hi, Can you help with the following (please refer to attached). If I understand the problem, both magnetic fields B1 & B2 need to change direction, due to the change in current (I) by replacing the positive with a negative ion. Your thoughts,
  12. Troll

    Space/time fields

    Given a toroidal field originating from a single point with the effect of compressing space/time infinitely at that single point and diminishing at the square of the distance with no compression at an infinite distance and given that this field were intersecting a like field what effect...
  13. E

    Magnetic Fields - Wires

    Wrong forum - sorry!
  14. E

    Electric Fields Question?

    Sphere A has a mass of 4.2*10^-2 kg and is tethered to a wall by a thin thread. Sphere a has an excess of 1.2 *10^12 electrons. Sphere B has a deficit of 3.5*10^12 electrons and is 0.23 m from Sphere A a) determine the angle between the thread and the wall b) determine the tension in the...
  15. H

    evil right hand rule (magnetic fields and velocity)

    Alright, this is stupidly simple. unfortunately i can't find the image that i am looking at online, and i don't have a scanner, and i'm too lazy to take a picture. oh and when i say up and down, i'll state that i mean in the y plane, except when i actually do mean out of or into the page so i...
  16. S

    Combined magnetic fields question

    Question (with solution): http://i.imgur.com/ZJoSa.jpg Let x,y be the axes on the sheet of paper where up and right are positive (like the question says actually). I do not get how the use of the right hand-rule should "convince me" that the field of each wire should cancel out in the first and...
  17. O

    Gravitational Fields Problem

    Could somebody please point me to formula's to use to solve this questions? I would really appreciate it. We will be sending astronauts to Mars in the near future. Mars has a radius of 3.43X10^6 m and a mass of 6.37X10^23 kg. Once there, they will drop things. How long would it take a...
  18. S

    Question about Coulomb's law and electric fields (I DO have the solutions)

    The last sentence is what I do not get. The solution says that the force is directed towards the q1 charge However, if I'm correct, in the part where the book explains the topic before assigning problems; it gives a different explanation. The following is my understanding: Given the first...
  19. Z

    Cathode-Ray Tubes and Electric Fields

    In a cathode-ray tube (CRT), an electron travels in a vacuum and enters a region between two "deflection" plates which have equal and opposite charges. The dimensions of each plate are L = 13 cm by d = 3 cm, and the gap between them is h = 2.5 mm (not to scale in the diagram). During a 0.001...
  20. Z

    Capacitors and electric fields

    A capacitor consists of two large metal disks of radius 2.4 meters placed parallel to each other, a distance of 0.7 millimeters apart. The capacitor is charged up to have an increasing amount of charge +Q on one disk and -Q on the other. At about what value of Q does a spark appear between the...