what is the donor concentration in n-type germanium of 1ohm-cm resistivity at 300K given electron mobility is equals to 3900cm^{}/V.s

Q. The electron mobility in N-type germanium is $3900{\text{cm}}^2/\text{V.s}$ and its conductivity is $6.24\text{mho/cm}$, then impurity concentration is
(Assume that the effect of cotters is negligible)

Q. What is the number density of donor atoms which must be added to a pure germanium semiconductor to produce an N-type semiconductor of conductivity $6.4X{10}^{2}oh{m}^{-1}{m}^{-1}$? The mobility of electrons in N-type germanium is $4X{10}^{-1}{m}^2{V}^{-1}{s}^{-1}$. Neglect contribution of holes to conductivity.

Q. The mobility of electrons in a semiconductor is defined as the ratio of their drift velocity to the applied electric field. If, for an n-type semiconductor, the density of electrons is ${10}^{19}{m}^{-3}$ and their mobility is $1.6m^2/(V.s)$ then the resistivity of the semiconductor (since it is an n-type semiconductor contribution of holes is ignored) is close to:

Q. What is the number density of donor atoms which must be added to a pure germanium semiconductor to produce an N-type semiconductor of conductivity $6.4\times {10}^2{\text{ohm}}^{–1}{\text{m}}^{–1}$ ? The mobility of electrons in N-type germanium is $4\times {10}^{–1}{\text{m}}^2{\text{V}}^{–1}{\text{s}}^{–1}$. Neglect contribution of holes to conductivity.

Q. The electron mobility in N-type germanium is $3900{\text{cm}}^2/v-s$ and its conductivity is $6.24\text{mho}/\text{cm}$; If the effect of cotters is negligible, then the impurity concentration will be