Questions in semiconductor

Select	Question
	The mobility of free electron is greater than that of free holes because
	The relation between the number of free electrons in semiconductors (n) and its temperature (T) is
	The electron mobility in N-type germanium is $3900 cm^2/v-s$ and its conductivity is $6.24 mho/cm$, then impurity concentration will be if the effect of cotters is negligible
	Which of the energy band diagrams shown in the figure corresponds to that of a semiconductor
	The energy band diagrams for three semiconductor samples of silicon are as shown. We can then assert that
	Carbon, silicon and Germanium atoms have four valence electrons each. Their valence and conduction band are separated by energy band gaps represented by $(E_g)_C$, $(E_g)_Si$ and $(E_g)_{Ge}$ respectively. Which one of the following relationship is true in their case
	A semiconductor dopped with a donor impurity is
	In a semiconducting material the mobilities of electrons and holes are $\mu _e$ and $\mu _h$ respectively. Which of the following is true
	Doping of intrinsic semiconductor is done
	In the forward bias arrangement of a PN-junction diode