2) I. II. III. In this problem, we will consider situations corresponding to three different long thin lines of matter containing charges: a copper wire carrying an electric current, a long amber rod that has been rubbed with fur and has a uniform excess of negative charge, and a beam of electrons passing through a vacuuln inside a cathode ray tube. They are represented schematically in the figure below. The direction of the electric current and of the electron flow are from left to right. A location marked it is indicated on the diagram and a set of directions with labels are shown at the right. E A. For each of the three cases (1,11, and III), indicate in what direction the electric and magnetic elds at the location it would point. If any of the fields are zero, write 0. Explain all reasoning. Slightly inconvenient but important physics truth: Although electrons may be owing in one direction, we dene 'current' to be owing in the direction opposite the motion of electrons. Direction of Electric Field Direction of Magnetic Field Case at x at x current carrying wire rubbed amber rod electron beam B. Now consider placing a positive charge at the location it. In one case it is stationary, while in a second case it is moving in the direction C. Indicate the direction you believe nearest to the total force the charge would feel . ( Ignore gravity and air resistance.) Explain all reasoning. Direction of force Direction of force Case on stationary + charge on + charge moving in C at x direction at it current carrying wire rubbed amber rod electron beam