An electron beam carries a total current of -500 µA in the az direction and has a current density Jz in the region 0 ≤ r ≤ 10^-4 m and zero in the region r > 10^-4 m. Electron beam velocity is given by Vz = (8 × 10^7 z) m/s. Calculate the volume charge density at z = 2 cm.
- A. 200 m C/m^3
- B. 10 m C/m^3
- C. -10 m C/m^3
- D. -200 m C/m^3