Q39: Within the green dashed circle shown in Figure P31.39, the magnetic field changes with time according to the expression B = t 3 t 2 , where B is in teslas, t is in seconds, and R = cm. When t = s, calculate
(a) the magnitude and
(b) the direction of the force exerted on an electron located at point P1, which is at a distance r1 = cm from the center of the circular field region.
(c) At what instant is this force equal to zero?
q =
pi =
g =