FIGURE Q24.2 shows cross sections of three-dimensional closed surfaces. They have a flat top and bottom surface above and below the plane of the page. However, the electric field is everywhere parallel to the page, so there is no flux through the top or bottom surface. The electric field is uniform over each face of the surface. For each, does the surface enclose a net positive charge, a net negative charge, or no net charge? Explain.
Tuesday, February 25, 2014 Particle orbit in homogeneous B-field Force and acceleration are perpendicular to velocity and velocity is constant Motion on a circle 2 Motion on a circle 2 F V a = m = R centrifugal acceleration F = qVB mV R = qB V qB νB= 2πR = 2πm cyclotron frequency ωB=2 πν B= qB (independent of V!) m 3 Example: Proton in B Field Consider a region of uniform magnetic field (green dots) coming out of the page with magnitude B = 1.2 mT. A proton with kinetic energy K = 8.48⋅10J enters the field, moving vertically from th