a) The room-temperature electrical conductivity of a semiconductor specimen is 25 (ohm-m)-1. The whole concentration is known to be 2.5E+19 m-3. The electron and hole mobilities for this material are 0.38 and 0.18 m2/V·s, respectively. Compute the electron concentration. (Use scientific notation.) b) On the basis of the result in part (a), is the specimen intrinsic, n-type extrinsic, or p-type extrinsic?