The electron concentration in silicon at T = 300 K is given by n(x) = 10^16 exp (-x/18) cm3
where x is measured in m and is limited to 0< or is equal to x < or is equal to 25 m. The electron diffusion coefficient is Dn = 25 cm2/s and the electron mobility is mun = 960 cm2/V-s. The total electron current density through the semi-conductor is constant and equal to Jn = 40 A/cm2. The electron current has both diffusion and drift current components. Determine the electric field as a function of x-bar which must exist in the semi-conductor.

Afoot bridge is made as a simple deck, 4 m long, with a cross section 2 m (wide) and 20 cm thick, and made of wood. the deck is supported at the two ends. the maximum load allowable on the bridge is 10 tons, provided it is uniformly distributed on the deck. to sense this load, a strain gauge is placed at the center of the bridge and its resistance is monitored. if the sensor has a nominal resistance of 350 s2 and a gauge factor of 3.6, what is the reading of the strain gauge at maximum load? the modulus of elasticity for the wood used in the construction is 10 gpa.