Germanium to which 5 x 1022 m—3 sb atoms have been added is an extrinsic semiconductor at room temperature, and virtually all the sb atoms may be thought of as being ionized (i. e., one charge carrier exists for each sb atom). (a) is this material n-type or p-type? (b) calculate the electrical conductivity of this material, assuming electron and hole motilities of 0.1 and 0.05 m2/v • s, respectively.

Amixture of slurry and mud is to be pumped through a horizontal pipe of diameter 500 mm. the fluid behaves as a bingham plastic with a yield stress of 30 pa and viscosity 0.04 pa. s. describe the effects of the shear stress through a transverse section of the pipe by plotting the variation in shear stress and velocity profile: (i) just before the slurry starts to move (ii) as the slurry flows when the pressure gradient is double that in part (i)