Review Sheet 2 - UM PHY126 Review Sheet 2 PHY126 Review...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
UM PHY126 Review Sheet 2 PHY126 Review Sheet 2 by Dr. Sa-Lin Cheng Bernstein 1. Magnetic field ~ B : Magnetic fields can be produced by magnets and electric currents. The magnetic field at a given point is a vector. The direction of ~ B at any point is indicated by the north pole of a small compass needle placed at that point. Magnetic field sources are essentially dipolar in nature, having a north and south magnetic pole. Units: tesla(T), and gauss. 1 gauss = 10 - 4 tesla. 2. Magnetic field lines : Magnetic field lines originate from the north pole and end on the south pole. They do not start or stop in midspace. The tangent to the magnetic field line at each point is the direction of the magnetic field at that point. No two field lines ever cross. The density in space of magnetic field lines around a particular point is proportional to the strength of the magnetic field at that point. The magnetic field is stronger in regions where the field lines are closer together. The number of lines per unit area passing perpendicularly through a surface is proportional to the magnitude of the magnetic field. 3. Magnetic fields and magnetic forces : A magnet or current creates A moving charge q experiences A current experiences ~ B (T) F = qvBsinθ F = IlBsinθ See Figure 21.9 and Figure 21.18 for RHR-1. The charge must be moving, for there is no magnetic force on a stationary charge. The velocity of the moving charge must have a component that is perpendicular to the direction of the magnetic field for there to be a non-zero magnetic force . θ is the angle between ~v (or ~ I ) and ~ B . A current is a collection of moving charges. If the moving charge is negative, the direction of the magnetic force is opposite to that predicted by RHR-1. ~ F is perpendicular to both ~ B and ~v (or ~ I ). ~ F cannot do work and change the kinetic energy of the moving charge. 4. The motion of a charged particle in ~ B : When ~v is perpendicular to ~ B , the charged particle follows on a circular path. r = mv qB . 1/9 February 20, 2007
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
UM PHY126 Review Sheet 2 See Figure 21.15. KE = eV = 1 2 mv 2 v = p 2 eV/m , therefore, r = 1 B s 2 V m q , or m = ( qr 2 2 V ) B 2 . 5. The torque on a current-carrying coil τ = NIABsinφ , where φ is the angle between the normal to the plane of the coil and the magnetic field. NIA is the magnetic moment.
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern