a) Knowing that ni for silicon at 300˚K is 1.5*10^10/cm3 calculate the resistivity of pure silicon at 300˚K. (un and up in pure silicon are 1400 and 500cm2 /Vs respectively) 

 b) At 600K, thermally generated carrier concentration in silicon (ni) reaches 2*10^15 . Calculate resistivity of pure silicon at 600˚K (assume that mobility values do not change with temperature).  

c) Calculate resistivity of silicon when doped with 10^15/cm3 concentration of phosphorous atoms. Repeat the calculation if boron doping is used instead of phosphorous. 

 d) What is the electrical resistance of a 1*2*10 mm3 slab of the abovementioned n-type doped silicon at 300˚K across its 10mm length. (resistance between the two 1mm*2mm faces). 

e) The same silicon slab is now used in a Hall magnetic field sensor. If the resistor is biased with a constant DC current of 100 microamps and the circuitry associated with it is capable of sensing voltages as small as 10microvolts, what is the minimum detectable magnetic field? If the doping level of the silicon slab increases, will the sensor sensitivity increase or decrease? (assume that the measured magnetic field is perpendicular to the 2mmx10mm face of the slab)