In a diode intended for high-speed switching, the excess-minority-carrier lifetime for holes is I ns. Using the value of hole mobility in doped silicon from Ex. 3.12 on page 143 of the Text, and the Einstein rela-tion (in Eq. 3.12 on page 141), find an estimate of the diffusion length in the forward-conducting diode. For this diffusion length, at what distance from the depletion-region edge will the excess hole density reach 10% of its value there?