Question

Problem 1a: Velocity Selector: Show that with the right ratio of electric to magnetic field strength a particle of velocity v will proceed through both fields in a straight line at constant speed (hint: you will need an equation containing v. Also: what does the straight line at constant speed give you?). Assume that the angle of the velocity vector relative to the magnetic field vector is 90 degrees. (15 points)

b: Show mathematically that the charge magnitude and sign do not matter.

c: Draw and label the electric field vector, the electric force vector, the magnetic field vector, the velocity vector and the magnetic force vector. Hint: start with the two force vectors. They have to add to zero. Then use the vector nature of the Eq = F(E) equation and the right hand rule to get the other vectors.) Assume that the particle is negatively charged. Use into and out of the page vector notation where necessary.

                                   

d. Explain in terms of what happens with the force vectors when the charge sign changes to allow a particle of either charge sign pass through the velocity selector at constant velocity v. In other words, explain physically why the particle charge sign makes no difference.

e. Explain in terms of what happens with the force vectors when the charge magnitude changes. In other words, explain physically why the charge magnitude makes no difference in the velocity selector.

Answer 1