Question

7. A charge, q-5uC moves through a uniform B-field, B 0.35 T, with a velocity, v = 200 m/s, at right angles to the field. Determine: (a) Fm on the charge; (b) mass of the charge if a -5x 10 m/s. A capacitor, C 047 μ, has a gap separation of 0.1 mm and has a voltage of 1000 volts. Determine: (a) the length of the capacitor's side assuming it is a square; (b) the capacitor's charge, Q; (c) the energy stored in the capacitor's E-field; (d) how much energy could be stored if we added a dielectric constant, k 1000, to the original capacitor. 8.

Answer 1

(a) q = -5 mu C B = 0.35 T v = 200 m/s magnetic force = q v B = 5 times 10^-6 times 0.35 times 200 F_m = 3.5 times 10^-4 N Ans (b) mass = ? m v^2/r = F_m (centripetal force = magnetic force) m v^2/r = q v B r = 5 times 10^4 m m times 200^2/5 times 10^4 = 3.5 times 10^-4 m = 4.375 times 10^-4 kg Ans