A p-type Ge sample with a resistivity of 40 -cm at 300 K is uniformly il- luminated with light that generates 103 excess electron-hole pairs per cm per sec. In the steady state, calculate the change in resistivity of the sample caused by the light. If the light is switched off at = 0, calculate the time required for the excess conductivity to drop to 10 percent of its value at t = 0. Assume T = 10-6 sec. A Si sample is doped with 105 donors cm. Calculate the excess electron and hole concentrations required to increase the sample conductivity by 15 percent. What carrier generation rate is required to maintain these ex- cess concentrations? Assume p 0.3, p= 10-6 sec and T = 300 K. =