for a Si conductor of length 5um, doped n-type at 10^15 cm^-3,calculate the current density for an applied voltage of 2.5 Vacross its legth. how about for a voltage of 2500V the electron and hole mobilities are 1500 cm^2/V-s and 500 cm^2/V-s,respectively, in the ohmic region for electric fields below 10^4V/cm. for higher fields, electrons and holes have a saturation velocity of 10^7 cm/s.