For a Si bar of length 5 mm, doped n-type at 10^15 cm-3, calculate the current density for an applied voltage of 2.5 V across its length. How about for a voltage of 2500 V? The electron and hole mobilities are 1500 cm2/V@s and 500 cm2/V@s, respectively, in the ohmic region for electric fields below 10^4 V/cm. For higher fields, electrons and holes have a saturation velocity of 10^7 cm/s.